For me, especially on a diesel boat with an old engine it is about the fumes. I have been on a bunch of wet exhaust diesel boats where the fumes were nauseating compared to a dry exhaust with a stack.
I think you need to research more on the " Detroit's are sensitive to back pressure" they are not scavenging thru ports in the cylinder, but have regular exhaust valves, just like a 4 stroke, if they were sensitive to back pressure you could NOT turbo charge them, and your video clearly shows that you CAN. I would get a muffler from a truck breakers yard. Keep up the great work.
Same thought here. Semi tractors for example, stacks on both sides of the cab. When I was little boy semis would puff smoke every shift, they were all Detroits in the 80s and double stacks were standard. Big chrome stacks, beautiful tractors.
Hey mate, excellent point. I knew these engines pushed the exhaust out through valves but I was thinking more traditional two stroke at the time for some daft reason. Rick has a naturally aspirated 8-71 in his workshop and he did mentioned that it isn't the same motor with turbos bolted on, there are some other differences apparently but I'm not sure what they are. The detroit diesel service manual does specify the maximum back pressure allowed so at least I have something I can measure once the install is done to make sure it is within spec.
@@DangarMarine I have never had my hand on a Detroit diesel, but USUALLY the difference between a NA and a turbo engine, is that the turbo version has about 2 points lower compression then the NA version, to compensate for the added charge volume (pressure) (as to not have to high cylinder pressure) a REALLY quick search shoved that the back pressure should be less then 3 psi on a NA diesel
@@BD-fw2gmAren't all two stroke outboards technically 'wet exhaust'? So that would seem to shoot down that the back pressure is an issue. That old system on Stu's boat with the wet box, water injected exhaust etc (that injected water takes up volume that should be space for the exhaust gases) would all cause back pressure. That is why the wet system is quieter- it is like an over muffled car exhaust- quiet but robs power because of poor flow rate. On conventional subs the exhaust gases are water sprayed after the mufflers when surface running at night - quieter, cooler ,lower infra red signature) but lowered out put power a bit. Also gave off lots of steam which is why the spray was used at night or in harbour only. Snorting exhaust was sub surface and not often done due to lots of reasons. being on the surface during the day was too silly to do in anything but surface transit runs. Go dry exhaust - way simpler to look after, fault find and repair. I have seen a 'wet muffler used on a trawler though - a normal steel muffler with a pumped water jacket around it - very quiet and safe to put your hand on at any time - and the water jacket had a line through it for fresh water heating .
If you're worried about back-pressure put an expansion chamber at the end of the exhaust manifold. The size of the chamber depends on the cc of the engine. All flow inhibitors after the chamber are near null, so you can use the biggest muff you would want to use.
That wet exhaust is like the duct work in my attic, right in the middle of everything and leaving no other useable space. Run your dry exhaust through an insulated box with air intakes at the top before going through the roof. Ditch the twin pipes for a good muffler and stack pipe. Simple is good. :)
I think in the case of your boat that you are spot on going to a dry exhaust. Noise will be the only downside I can see. Bravo, on a great explanation on the merits of both.
Well explained Stu, having NO prior knowledge of the two types of systems.....I like the dry exhaust version myself simply because it is simple and maintenance free with little risks associated with it. I can see the opposite with the wet exhaust, high maintenance and high risk due to pump failure or leakage...the space gained form removal of the wet exhaust is substantial too. Well done Stu keep up the good work mate 👍
If your water pump fails, it isn't the exhaust that will be your largest problem because your motor won't be cooled either. The risk of pump failure between the two exhausts don't change unless you have more than one water pump for your wet exhaust, which isn't usually done.
Man I LOVE your tidy-up methodology. As for the exhaust, it appears (to my un-educated mind) that the dry exhaust is clearly the way to go - particularly as the "infrastructure" is already there from the previous dry installation. Simplicity is the basis of a sound and reliable solution.
This is Chad,all the way from Georgia, USA.just wanted to say hi and thank you for your videos. I really enjoy and appreciate you and sharing your experience with your boat. I hope to retire on one myself in a few years.take care.
Canadian here. Don't sweat the messy stuff it's hard to do it all, all of the time. Life gets pretty busy and drawn out to do it all. There's only you doing this boat your doing a great job of it. It would be better if you could be with Brupeg or others to help. Keep on doing your best. God Bless you.
Thanks Dennis. Yes, I'd love to be up at the yard with Brupeg. I was planning to head up there this season but I'm running behind schedule so unfortunately it looks like it isn't going to be until next year now.
Here in Maine, there is a law against commercial boats using wet exhaust. Seems some one thinks that the wet exhaust is more contaminating to the ocean. The local fishermen have found that having a dry exhaust is nicer as in during our fridgid winter months, the exhaust pipe is keeping the cabin and engine warm
"Seems some one thinks that the wet exhaust is more contaminating to the ocean" Do you not know what is in the exhaust? The water near boat docks is some of the most toxic. Who would have thought that mixing carbon monoxide, carbon dioxide, nitrogen dioxide, sulfur dioxide, benzene, formaldehyde, ethylbenzene, hydrocarbons, VOC, particulate matter, and soot into the water is contaminating it. Oceans are big but for fish it would be like riding a motorcycle behind a diesel truck that is modded "rolling coal" in your face. Sure you won't instantly die but its not healthy for you even though there's an abundant amount of air for it to mix within the atmosphere just like the ocean has tons of water, everything in the imminent domain is getting some of that toxicity. It may not be as bad as an oil spill in the ocean but it's still contamination. I love boating and cars but it's ultimately just what happens with petroleum based combustion engines
Your doing a great job man. One point about a dry exhaust. It's much simpler, therefor there is less to go wrong at the worst possible time. Like at night, where you can't see the shore, or any lights, and the weather is bad, and you need all the power your engine can give you. This is not the time, to have an exhaust issue. So, if I were you, I would go with, and keep the dry exhaust. Just one less thing to have to worry about.
Happy McJoyjoy excuse me, what?! 😂 I presume you’re referring to e=mc2, that is nothing but an abbreviation of his equation, have a google and see the actual equation in its full and then consider if it’s uncluttered.
desk of one of the key drivers of inflationary cosmology: www.google.com/url?sa=i&url=https%3A%2F%2Fwww.boston.com%2Frealestate%2Fgalleries%2Fspringsweep%2F13.htm&psig=AOvVaw0SyeX09ERzpm8TquoS2cqF&ust=1603586045222000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCNjQjdf9y-wCFQAAAAAdAAAAABAW
Just a note to Americans: US Coast Guard Regulations require WET (water jacketed) exhaust manifolds on all vessel inboard engine installations. There are insurance carrier implications as well.
I've NEVER Heard a Detroit So Quiet as yer Mate's was through that dry muffler! That's a damned GOOD Muffler, I'd call the guys who built it, they Know What They're Doing....If they can Silence the V-8 that well, your 4-71 will be No Challenge.Hate to see the Price Tag on that Stainless, though. Also, you want to recall that when your boat was built, nobody MADE a Muffler that WOULD Quiet a Detroit, which is no doubt why they Converted her to Wet. And you DEFINITELY Need the space. With the Wet piping Gone, you could also build a clamshell box around your motor, Soundproof the Hell out of it, and so keep it down to a dull rumble throughout the boat, Below Deck. BTW, you could also Shop for your flex-pipe and the New-Style Band-clamps at a Truck Parts store, instead of a Marine store, which should get you a BIG Price Discount. And the New-Style clamps seal MUCH better, and easier to install also. You just want to Run them a day or so, and Re-torque the bolts, after they get hot and Seat In. I can't Get OVER the Muffler on that boat! Even at the Helm it was just loud enough to hear the engine, so you could tell if it started running rough or missing..That was GREAT. I really LIKED you Shop Cleanup, BTW.
Thanks mate, appreciate all the info. I'll definitely be giving the manufacturer of Dave's muffler (Dieselex from memory) a call and see what they can do for me. :)
We've run them for YEARS hereabouts in trucks and equipment, never heard a Quiet one, even with BRAND NEW Mufflers. All through the Seventies. Greyhound and other passenger coaches with Detroits were loud, also and they were Muffled to Death. It's the Nature of the Two Stroke Detroit, and why I like them. Neighbor had a sawmill powered by a 4-71 like Stu has, it had an 8-inch straight pipe, and when he sawed, we could tell what kind of wood he was in by the sound of the motor. It was a Mile Away, and sounded like it was in our driveway. Three hills between with trees. It got on people's nerves after a couple days. A friend of my Dad's ran Cabovers with Buzzin Dozens, his always had New Mufflers on it, and we could hear him pulling up out of the Laurel Gorge with 50 tons of coal On. TEN Miles away. Dad drove a 359 Pete, the ORIGINAL Extended Hood, Buzzin Dozen and 13-speed, and I could listen to him coming home from Eight miles away, Empty. I don't know about in Boats, but don't tell ME I don't know Detroits, Little Boy, the first engine I ever rebuilt was an 8V71 T. 35 years ago. @@EDesigns_FL
I don't know how long Dieselex has been Around, And I guess Trucks and bulldozers Do Work Harder than Boat engines, except maybe a Tug or Pushboat.I don't know what alloy of SS the muffler and bandclamps today are, but the ones WE had didn't corrode all Winter long in the roadsalt and calcium....@@EDesigns_FL
Good job of showing the differences in the two systems. I think I might like the dry system better too. A lot of extra parts to make the wet system work and takes up a lot of space. Also, you're smart leaving the wet system in place until you're sure of what works best. And checking with the exhaust experts might convince you straight away to stay with the wet system once you find out what the dry system will cost you in performance and noise.
Another awesome video! My opinion after listening to what you said is that a dry exhaust is actually less complex than a wet system. I spent 9 years rebuilding an EH with a turbo motor and basically to compensate for backpressure issues from mufflers etc an increase in diameter might be needed. One thing to consider might be because the exhaust was so short on your boat may have made it quite loud. All of our generators at work use like an eggshell foam lining in the outer skin and it works extremely well that could be an option if it became an issue. Thanks again for an awesome vid!
I think you are doing great, being smart and asking questions and doing some research will pay off, running a dry exhaust before making a decision is smart, taking it apart with the possibility of reinstalling it if you had to might be wise also.
You did it again Stu, excellent video! You manage to more than just cover a subject as your exhaust, but for me you draw me into Dangar island. I hope to visit Australia someday, wish I could drive the bus there. This is great, I could listen to raconteur Rick all day with his colloquialisms. What it comes down to is a good person surrounded by other good people telling their stories along the way. Thanks again!
I am currently re-fitting a steel trawler with a DD 4-71. She came with dry exhaust and I'm keeping her that way. Her engine is just below the cabin/helm and yes, 2 cycle Detroits are noisy. I've fitted a false flood in the cabin with 1" of rigid foam on top of a rubber mat over the steel decks, then plywood. Helps immensely. One clue is that you'be got to get a complete seal between the living space/engine compartment. Even a small opening will allow a lot of noise to pass. A huge thanks for researching the muffler! Mine's got one, but I suspect it's not the best configuration. Once you selected something I'll be following in your wake! I've also considered a removable pipe extension on top of the stack to move the actual exhaust port up higher and away from the aft deck. Thin wall stainless ducting ought to work. I'll report back if it works. Why all the off-topic comments on the flag? Seems like hyper-vigilance. The boat was a perfect example for the video, and I for one couldn't care a wit about what sort of flag anyone flies from their transom.
Hey Robert. Glad to hear I've got someone to compare notes with! I'm looking forward to talking to Dieselex and seeing what type of muffler(s) they recommend. One thing I should have commented on more in this video is just how much difference sealing the engine room makes to the overall noise - it is only 50% about the exhaust system. Couldn't agree more about Rick's flag - it's his life to live exactly as he choses.
Wow, didn't expect a cleaning video from Dangar Stu.👌😄 7.08. My experience of 2-stroke engines is that exhausts are purely expansion chambers which do little muffling. I know there are equations to be worked out in making a petrol expansion chamber, not sure about diesel. Maybe this is why it was converted, because of the combination of 2-stroke and noise? I used to drive a Detroit diesel truck in the seventies and it WAS noisy even beside other trucks way back then, when everything was louder.
When I was a scout we had a 50 foot boat with a 671 diesel, it had wet exhaust with side discharge, that exhaust was great fun as it shot a fare size of water about fifteen to twenty feet while underway.
Good vid Stu. One other option that a lot of commercial vessels use for a wet exhaust is to run the pipe externally and use it as a sponson. This is very popular in WA on cray boats.
I work on steel boats, we cool the exhaust manifold using the pressurised coolant from the engines cooling circuit. Obviously you need a manifold with some sort of water jacket. Also Instead of having pipework on the outside of the boat for keel cooling we just weld tanks to the inside hull. They only need to be 25-35 mm deep but with a large area to allow heat to transfer through the steel hull into the sea. It's simple and works well. Love the videos by the way and I love working on boats.
I'm a fan of wet exhausts but I think dry is a better option for your boat especially given the space you would gain. Great to hear the reference to Mighty Car Mods... Thanks for presenting a great series of videos while restoring this boat. You keep it real. Cheers, Steve from Mount Gambier
I suspect that flap clanking is the result of an engine not running on all cylinders. A Detroit will run in almost any condition. With the amount of smoke coming out on acceleration , this engine needs a tech to diagnose before it starts running away on its' own lube oil. I didn't get a good look, but if it's an 8V-71T, it's about 3 times the engine that boat needs.
Nice explanation, very clear. I have worked on a trawler with a dry exhaust and it was noisey, but there was no muffler, or soundproofing fitted. A steel boat will always be noisier than a wooden one as the wood absorbs sound, while the steel echos and vibrates more.
Filming Dave's boat made me realise just how much of the noise is direct mechanical noise from the engine, something that is only worse in steel. I'll definitely do as much insulating as I can too.
1 take out the wet exhaust and putting the dry exhaust back as it makes more sense and gives you more room.. I'm woching all ur videos to day from the start. Verry good videos Ray from England..give usr a shout out ples
Dry just seems safer and more simple. When your out at sea, simple can mean the difference between life and death. Or at least a huge pain in the arse!
Dangar Marine well I’ll say we all ought to just be who we are, the world would probably be a lot less trouble filled, I am straight but hats off to the guy for just being himself, btw stu your trawler is awesome sure wish I had something like that down here on the gulf coast of Alabama! Can’t wait to see you underway soon!
Followed you home from Brupeg. Some very important and interesting aspects to consider when restoring maritime real estate to safe and yet economical use and operation. Thanks, enjoyed it.
I live in the Pacific Northwest of United States. And one of the biggest benefits I think of a dry exhaust with a stack is if you get any type of seasickness not breathing in the diesel fumes really helps.
I had a dry exhaust until I had to have a mass removed from my colon...so more of a wet exhaust now. Can't say I have noticed a noise level difference at all.
Hi there :) Regarding the detroit diesel... there is no need to remove the turbo chargers. Remove the aftercooler/aircooler dismantle by taking off all its walls and clean it thoroughly with high pressure wash using something like degreaser or petrol to clear all the carbon soot which has collected within due to the exhaust manifold leak Stop the exhaust manifold leak and replace the air filters that will stop the smoke Since its a old detroit diesel the fuel pump on that engine does not have a boost compensator thus the fuel pump is injecting fuel at even though it is not getting enough boost IF there was a boost compensator with the same issue the engine would not smoke but you won't be able to reach max rpms In essence the engine is choking Hope this helps :)
IF I ever have a wet/dry exhaust conundrum Now I know. 😁🤣Also Stu , you shouldn’t take sooo much time acquiescing to those who say CleanUp! Takes too much valuable time away from your excellent educational boating videos. 😜😁🤣🤣 Keep up the good work! 👍
Well Stu, I'm not a marine mechanic but I do deal with diesel engines as a truck driver. My thought is dry exhaust is a better bet. My main reason is that wet involves salt water, steel, and heat and given the corrosive nature of salt alone it looks like a lot of potential trouble with corrosion. That and the dependency on the pump. Dry exhaust going straight up encased in a housing say 5" larger in diameter open at the top and bottom would draw air like a chimney around the exhaust pipe cooling it and providing some natural ventilation in the engine room. Seems like a lot less to go wrong. My thought is go high up with the muffler as your friend did. Should be available in stainless steel and I believe the engine manufacturer should have the spec for optimal back pressure rating for the muffler. Anyway, that's my thoughts on it. Love the videos, I always look forward to the next one! Cheers mate!
I say dry, more space and maintenance possibilities is way higher priority than just noise. Noise should be secondary to maintenance. Also build your self a ladder for below deck. Obviously you’ll be doing down there often. Just a few steps should help a ton
Great video. Having been around car and industrial motors most of my life, don't assume a 4 cylinder industrial diesel will sound softer than a V8. It's totally how the exhaust is designed. Since the previous owner obviously switched to the wet system because he was loosing his hearing standing next to a dry exhaust system, really do your research-find a 471 in your area that has a dry system and check it out! Believe me, they'll be easy to spot.
Good idea leaving the wet system in place until you are satisfied with the dry. There is less possible system failures with the dry. A proper muffler, sound deadening applications should do the trick. Will you be installing a gen set? Also with the stuffing box cooling the shaft nothing changes wet or dry. Looking good brother! I believe your wheel house will be quiet as compared to your friends boat as the engine is under the back deck instead of below the bridge.
@@mastermachineman1462 No. There is no mixing lube oil with fuel on a Detroit diesel. Other 2-strokes use the crankcase area to pressurize the intake air to help push the exhaust out of the cylinders and replace it with fresh air. When this is done it is difficult to use the crankcase area as a lube oil reservoir. This is the reason other 2-strokes mix oil with the fuel, to lubricate the crankshaft, pistons etc. A Detroit does have its' lube oil reservoir in the crankcase and uses an air pump to pressurize the intake air and help push the exhaust out of ports in the lower cylinder walls. You may have seen these pumps before, mounted on the top of old hot rod car engines. They were commonly adapted to use as one of the original super-chargers for gasoline engines!
chop the lot out, use a flexi pipe up to deck head, then across to the side, and down to exit just above the water line , if need be you can use a rubber muffler outside to lesson noise and stop any backwash......... I have noticed with Stack Pipes if they are not high enough you get a back swirl of exhaust in the after deck when going forward, but a canopy could remedy it........... good luck with the project I have done a few of them mostly on wooden boats......cheers UK..
Yes, I can see how the vacuum behind the wheelhouse could draw the exhaust fumes back down. My big worry is that I go back to dry and then go, ah, that's why they got rid of it. ;)
If you don't have a DPF on the dry exhaust of an old diesel you will be raining down some VERY toxic chemicals on anyone downwind. Also, judging noise level of an engine at idle is like judging the speed of a horse on a lead rope :-) Enjoying the story Stu - great stuff.
All sort of stupid conversions have been done to my boat by the second owner. The guy who build it know what he was doing. I would really like to convert it back to dry and go back to 24V instead of the 12V I have now. Hope you will go for the dry exhaust. 4-71's are sweet. I could listen to them all day with a good muffler. Wet exhaust is just like some one is puking at the back all the time :-)
Very informative Stu...thanks for the vid and great to see a couple of classic Detroit Diesels purring ...what a great sound. I'm thinking Brupeg has a dry stack ??
Dry exhaust system seems to have advantages over the wet exhaust, below deck space and pump fail seem to be a disadvantage for the wet exhausts system. Nice upload today very interesting but a bit to short. I can watch your boat escapades for hours, looking forward to your next upload. Regards from a uk land lubber pom😊
I know nothing about boats but loving this series your clean up was brilliant pissing my self can't wait for the next installment Thank you for the vids
Having run quite a few boats with Detroit’s you can’t have enough sound insulation on a Them. No matter what you do make sure you have a considerable amount of insulation and a well designed muffler.
Great vid Stu. I've seen some wet exhaust boats with the outlets at the stern but opening out either side rather than the transom. I realize now the point probably is to combat the fume issues in the following sea/wind situation by ejecting exhaust out and away from the boat.
Hi mate...keep up the great work, your vids are awesome and cannot wait till the next instalment ....can't believe I'm getting excited about wet or dry exhausts 😂
Watch your vids all the time and actually lived just where you are. From experience, please keep the wet exhaust if you are contemplating long voyages as a dry will drive you nuts! The constant and pounding Lulululul will make you want to want to get back to shore even faster, thus slapping the piss out of blue water cruising. Thats if thats your intention with this boat of course. Great vids! thanks for sharing!
Wet exhaust design: The exhaust pipe from the turbo or manifold should be water jacketed until it falls at least a foot towards the exhaust outlet. Sea water cooling from the heat exchange enters at the top of the jacket and exits through a water curtain into the exhaust pipe. The water curtain should allow a one or two PSI back pressure in the water jacket to maintain complete cooling. In my boat I have a low pressure water gauge installed in the sea water cooling system. It's the water jacket and cooling water which silences the exhaust. Gauges installed for my boat engine: coolant, oil pressure, turbo boost, tachometer, heat exchange sea water pressure and engine hour gauge. All these are necessary to monitor the engine performance and maintenance, running hours between oil change, etc. I hope this helps. Cheers Chris.
I think going back to a dry exhaust would be great! I’d just improve the muffling and insulation and then you’ll be set! Maintenance space is so helpful!
I've owned several trawlers and sailboats all with wet exhaust. Even though you can cover a dry exhaust pipe it will still put out a lot of heat that will collect in the engine room. You will not be happy with that. Other systems will be affected by the heat. If you simply redesigned the wet exhaust to use space more efficiently you would have the best of both worlds.
I have owned and operated both wet and dry exhaust vessels. The dangers of a wet exhaust are: (A) going hard astern, where the sea washes back into the turbochargers, Particularly vulnerable craft are low slung speedboats. No room for a high-rise bend in the exhaust pipe before overboard skin fitting. (B) Heavy rain or leaky stern glands; especially low slung powerboats unattended at moorings or marina dock. These can cause entry of seawater into exhaust manifold and cylinders; wrecking the entire engine. As a boatyard proprietor I have had various customers with these problems. A dry exhaust with a large muffler (exhaust silencer) is the best, hands down. Raw cooling water appearing from skin fittings above the waterline then confirms that the heat exchanger is being supplied and no other possibility. As far as occupying space is concerned; no reason dictates funnel must be amidships. Awnings, Radar and antennae goalposts aft can carry exhaust pipes on either side.
Just for your info my father in law had a 52' Riviera with twin 400hp Detroits. Both motors were wet exhausts. When the boat was just cruising the motor noise was to the point, both inside and outside, very noisy. This was even though the engine bay under the rear floor was soundproofed. Also if you got a tailing wind the fumes coming from the twin rear wet exhausts was fairly powerful on the rear deck area causing us to have to go inside and close the rear door..unless the front hatch lids were opened but that was not possible in heavier seas. I have been on boats with stacked dry exhausts and they are quite different in that it does seem quieter and the fume problems were also a lot less depending on winds. Also access to both engines was extremely difficult, as you've pointed out, for maintenance on the Riviera because of the exhaust system. Just thought I'd put my two bobs worth on here. 😁🇦🇺👍🏻
When you do your dry exhaust I know everyone loves a nice shinny stainless exhaust but I would really recommend doin a black ceramic coating on it after it’s all been made and fitted will also help with the radiating heat and also big part help agains corrosion even tho it will be stainless the heat cycle through it will allow it to start and then after that in the engine bay still heat wrap it aswell but I wouldn’t heat wrap straight to the mild steel section in engine bay cause it will still corrode and ends up cooking the exhaust and makes it prone to fatigue and cracks, Pro Coat at Wyong are reasonably priced and do a great job had my rear turbo housing and manifold done by them, I’m local to somersby would love to come check out this awesome project and maybe volunteer some of my time and ideas Keep up the great work !!
In your boat Stu go with the dry. Less issues and your boat is already set up for it. I end up removing other's upgrades on every boat I touch so don't worry about that..
I'd definitely go back to the dry exhaust, too. That freed up space below deck is too good not to take advantage of. And less holes in the hull is always a good thing. I'd invest in a good quality one like your mate had. Silence is golden.
My kind of clean-up, Stu. I vote dry exhaust, too, BTW, even though my 48 foot wooden bird has a wet exhaust. The only reason I don't change it either is because it works fine, and it would be too much work to change over. If I was restoring about like yours though, and I had a choice, it would be dry exhaust and keel cooling for sure. Any through-hulls that you can eliminate has to be considered a positive.
go dry you won't be sorry. I have thrty years engineering fishing boats in Alaska. leave lots of air space in your stack!!!! heat rises. put a big blower to force air into engine room from out side. wrap all pipe well use as much sound deadener as you can afford
howdy mate, We switched from wet exhaust to dry on our small push boat for our dredging business. It worked out much better.one less sea strainer and pump to worry about.
Best cleanup ever! Put the naysayers where they belong. Great video. Been around boats my whole life, fresh water, salt water, etc. Love your take on things. Keep 'em coming.
Plus one for the dry option, I feel its much more suited to your situation. It wouldn't surprise me if the last guy converted it to wet exhaust based on hopes and long standing feelings about this subject as some are staunch believers in one or the other.
Another thing to consider in the wet exhaust system, is that if the water is injected into the exhaust at or close to the water line, a siphon break is a good idea to install in the raw water discharge line with a loop above any possible water line. This ensures no water can siphon past the raw water pump and fill the exhaust. This is done primarily in sailboats and other vessels where the engine is below the waterline.
Great video. I like the idea of going back to dry exhaust. Less complicated and frees up internal space in the engine room.
For me, especially on a diesel boat with an old engine it is about the fumes. I have been on a bunch of wet exhaust diesel boats where the fumes were nauseating compared to a dry exhaust with a stack.
I think you need to research more on the " Detroit's are sensitive to back pressure" they are not scavenging thru ports in the cylinder, but have regular exhaust valves, just like a 4 stroke, if they were sensitive to back pressure you could NOT turbo charge them, and your video clearly shows that you CAN. I would get a muffler from a truck breakers yard. Keep up the great work.
Same thought here. Semi tractors for example, stacks on both sides of the cab. When I was little boy semis would puff smoke every shift, they were all Detroits in the 80s and double stacks were standard. Big chrome stacks, beautiful tractors.
Hey mate, excellent point. I knew these engines pushed the exhaust out through valves but I was thinking more traditional two stroke at the time for some daft reason. Rick has a naturally aspirated 8-71 in his workshop and he did mentioned that it isn't the same motor with turbos bolted on, there are some other differences apparently but I'm not sure what they are. The detroit diesel service manual does specify the maximum back pressure allowed so at least I have something I can measure once the install is done to make sure it is within spec.
@@DangarMarine I have never had my hand on a Detroit diesel, but USUALLY the difference between a NA and a turbo engine, is that the turbo version has about 2 points lower compression then the NA version, to compensate for the added charge volume (pressure) (as to not have to high cylinder pressure) a REALLY quick search shoved that the back pressure should be less then 3 psi on a NA diesel
@@BD-fw2gmAren't all two stroke outboards technically 'wet exhaust'? So that would seem to shoot down that the back pressure is an issue. That old system on Stu's boat with the wet box, water injected exhaust etc (that injected water takes up volume that should be space for the exhaust gases) would all cause back pressure. That is why the wet system is quieter- it is like an over muffled car exhaust- quiet but robs power because of poor flow rate. On conventional subs the exhaust gases are water sprayed after the mufflers when surface running at night - quieter, cooler ,lower infra red signature) but lowered out put power a bit. Also gave off lots of steam which is why the spray was used at night or in harbour only. Snorting exhaust was sub surface and not often done due to lots of reasons. being on the surface during the day was too silly to do in anything but surface transit runs.
Go dry exhaust - way simpler to look after, fault find and repair. I have seen a 'wet muffler used on a trawler though - a normal steel muffler with a pumped water jacket around it - very quiet and safe to put your hand on at any time - and the water jacket had a line through it for fresh water heating .
If you're worried about back-pressure put an expansion chamber at the end of the exhaust manifold. The size of the chamber depends on the cc of the engine. All flow inhibitors after the chamber are near null, so you can use the biggest muff you would want to use.
That wet exhaust is like the duct work in my attic, right in the middle of everything and leaving no other useable space. Run your dry exhaust through an insulated box with air intakes at the top before going through the roof. Ditch the twin pipes for a good muffler and stack pipe. Simple is good. :)
Yes, I think when people do installs like that they are only thinking of making their own day easier without any thought to the future.
I think in the case of your boat that you are spot on going to a dry exhaust.
Noise will be the only downside I can see.
Bravo, on a great explanation on the merits of both.
Brilliant 2 vids this week. That clanking from the wet exhaust cover would have driven me completely insane
That rhythmic clanging would drive anyone nuts. Stick a rubber strip on the flap.
Yeah that was driving me nuts just in the video.
Like said a rubber flap would stop that.
@@Voltaire321 They were a bit too drunk to pay any never no mind... not that that's a bad thing!
I think with proper maintenance on that boat/motor it'd be different.
Well explained Stu, having NO prior knowledge of the two types of systems.....I like the dry exhaust version myself simply because it is simple and maintenance free with little risks associated with it. I can see the opposite with the wet exhaust, high maintenance and high risk due to pump failure or leakage...the space gained form removal of the wet exhaust is substantial too. Well done Stu keep up the good work mate 👍
If your water pump fails, it isn't the exhaust that will be your largest problem because your motor won't be cooled either. The risk of pump failure between the two exhausts don't change unless you have more than one water pump for your wet exhaust, which isn't usually done.
It isn't common, but this boat does currently have one pump for the exhaust and one for the engine.
Man I LOVE your tidy-up methodology. As for the exhaust, it appears (to my un-educated mind) that the dry exhaust is clearly the way to go - particularly as the "infrastructure" is already there from the previous dry installation. Simplicity is the basis of a sound and reliable solution.
This is Chad,all the way from Georgia, USA.just wanted to say hi and thank you for your videos. I really enjoy and appreciate you and sharing your experience with your boat. I hope to retire on one myself in a few years.take care.
Hi Chad! :)
There's more smoke than a cypress hill concert and that dude is just so calm about the situation, brilliant.
Canadian here. Don't sweat the messy stuff it's hard to do it all, all of the time. Life gets pretty busy and drawn out to do it all.
There's only you doing this boat your doing a great job of it. It would be better if you could be with Brupeg or others to help.
Keep on doing your best. God Bless you.
Thanks Dennis. Yes, I'd love to be up at the yard with Brupeg. I was planning to head up there this season but I'm running behind schedule so unfortunately it looks like it isn't going to be until next year now.
Here in Maine, there is a law against commercial boats using wet exhaust. Seems some one thinks that the wet exhaust is more contaminating to the ocean. The local fishermen have found that having a dry exhaust is nicer as in during our fridgid winter months, the exhaust pipe is keeping the cabin and engine warm
Really? I feel like tons of the lobster boats I’ve seen still have wet exhaust
"Seems some one thinks that the wet exhaust is more contaminating to the ocean"
Do you not know what is in the exhaust? The water near boat docks is some of the most toxic. Who would have thought that mixing carbon monoxide, carbon dioxide, nitrogen dioxide, sulfur dioxide, benzene, formaldehyde, ethylbenzene, hydrocarbons, VOC, particulate matter, and soot into the water is contaminating it.
Oceans are big but for fish it would be like riding a motorcycle behind a diesel truck that is modded "rolling coal" in your face. Sure you won't instantly die but its not healthy for you even though there's an abundant amount of air for it to mix within the atmosphere just like the ocean has tons of water, everything in the imminent domain is getting some of that toxicity. It may not be as bad as an oil spill in the ocean but it's still contamination. I love boating and cars but it's ultimately just what happens with petroleum based combustion engines
Your doing a great job man. One point about a dry exhaust. It's much simpler, therefor there is less to go wrong at the worst possible time. Like at night, where you can't see the shore, or any lights, and the weather is bad, and you need all the power your engine can give you. This is not the time, to have an exhaust issue. So, if I were you, I would go with, and keep the dry exhaust. Just one less thing to have to worry about.
Wow never thought I’d be interested in boats being a car mechanic/enthusiast but this is extremely interesting. I’ll keep watching for sure!
Great explanation of W vs D.
Like your approach...go with D and KEEP with W until D is proven correct.
Keep the great videos coming.
Albert Einstein famously pointed out that "If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?"
A DEAD ass.
An ordered mind.
Aside from the Modern strange stuff, an artist's pallet is a complete mess, but from it comes some beautiful paintings.
Happy McJoyjoy excuse me, what?! 😂 I presume you’re referring to e=mc2, that is nothing but an abbreviation of his equation, have a google and see the actual equation in its full and then consider if it’s uncluttered.
desk of one of the key drivers of inflationary cosmology: www.google.com/url?sa=i&url=https%3A%2F%2Fwww.boston.com%2Frealestate%2Fgalleries%2Fspringsweep%2F13.htm&psig=AOvVaw0SyeX09ERzpm8TquoS2cqF&ust=1603586045222000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCNjQjdf9y-wCFQAAAAAdAAAAABAW
Just a note to Americans: US Coast Guard Regulations require WET (water jacketed) exhaust manifolds on all vessel inboard engine installations. There are insurance carrier implications as well.
Why is this?
I've NEVER Heard a Detroit So Quiet as yer Mate's was through that dry muffler! That's a damned GOOD Muffler, I'd call the guys who built it, they Know What They're Doing....If they can Silence the V-8 that well, your 4-71 will be No Challenge.Hate to see the Price Tag on that Stainless, though. Also, you want to recall that when your boat was built, nobody MADE a Muffler that WOULD Quiet a Detroit, which is no doubt why they Converted her to Wet. And you DEFINITELY Need the space. With the Wet piping Gone, you could also build a clamshell box around your motor, Soundproof the Hell out of it, and so keep it down to a dull rumble throughout the boat, Below Deck. BTW, you could also Shop for your flex-pipe and the New-Style Band-clamps at a Truck Parts store, instead of a Marine store, which should get you a BIG Price Discount. And the New-Style clamps seal MUCH better, and easier to install also. You just want to Run them a day or so, and Re-torque the bolts, after they get hot and Seat In. I can't Get OVER the Muffler on that boat! Even at the Helm it was just loud enough to hear the engine, so you could tell if it started running rough or missing..That was GREAT. I really LIKED you Shop Cleanup, BTW.
And ?
Thanks mate, appreciate all the info. I'll definitely be giving the manufacturer of Dave's muffler (Dieselex from memory) a call and see what they can do for me. :)
We've run them for YEARS hereabouts in trucks and equipment, never heard a Quiet one, even with BRAND NEW Mufflers. All through the Seventies. Greyhound and other passenger coaches with Detroits were loud, also and they were Muffled to Death. It's the Nature of the Two Stroke Detroit, and why I like them. Neighbor had a sawmill powered by a 4-71 like Stu has, it had an 8-inch straight pipe, and when he sawed, we could tell what kind of wood he was in by the sound of the motor. It was a Mile Away, and sounded like it was in our driveway. Three hills between with trees. It got on people's nerves after a couple days. A friend of my Dad's ran Cabovers with Buzzin Dozens, his always had New Mufflers on it, and we could hear him pulling up out of the Laurel Gorge with 50 tons of coal On. TEN Miles away. Dad drove a 359 Pete, the ORIGINAL Extended Hood, Buzzin Dozen and 13-speed, and I could listen to him coming home from Eight miles away, Empty. I don't know about in Boats, but don't tell ME I don't know Detroits, Little Boy, the first engine I ever rebuilt was an 8V71 T. 35 years ago. @@EDesigns_FL
I don't know how long Dieselex has been Around, And I guess Trucks and bulldozers Do Work Harder than Boat engines, except maybe a Tug or Pushboat.I don't know what alloy of SS the muffler and bandclamps today are, but the ones WE had didn't corrode all Winter long in the roadsalt and calcium....@@EDesigns_FL
@@EDesigns_FL the engine was on a high idle. You could see that with throttle.
Good job of showing the differences in the two systems. I think I might like the dry system better too. A lot of extra parts to make the wet system work and takes up a lot of space. Also, you're smart leaving the wet system in place until you're sure of what works best. And checking with the exhaust experts might convince you straight away to stay with the wet system once you find out what the dry system will cost you in performance and noise.
Wet exhaust - farting in the bath.
Dry exhaust - farting during the day.
Oh, and great cleanup too! Cheers from New Zealand!
Another awesome video!
My opinion after listening to what you said is that a dry exhaust is actually less complex than a wet system.
I spent 9 years rebuilding an EH with a turbo motor and basically to compensate for backpressure issues from mufflers etc an increase in diameter might be needed.
One thing to consider might be because the exhaust was so short on your boat may have made it quite loud.
All of our generators at work use like an eggshell foam lining in the outer skin and it works extremely well that could be an option if it became an issue.
Thanks again for an awesome vid!
I think you are doing great, being smart and asking questions and doing some research will pay off, running a dry exhaust before making a decision is smart, taking it apart with the possibility of reinstalling it if you had to might be wise also.
You did it again Stu, excellent video! You manage to more than just cover a subject as your exhaust, but for me you draw me into Dangar island. I hope to visit Australia someday, wish I could drive the bus there. This is great, I could listen to raconteur Rick all day with his colloquialisms. What it comes down to is a good person surrounded by other good people telling their stories along the way. Thanks again!
Wow, I'm basically an expert now on boat exhausts. Cool!
I am currently re-fitting a steel trawler with a DD 4-71. She came with dry exhaust and I'm keeping her that way. Her engine is just below the cabin/helm and yes, 2 cycle Detroits are noisy. I've fitted a false flood in the cabin with 1" of rigid foam on top of a rubber mat over the steel decks, then plywood. Helps immensely. One clue is that you'be got to get a complete seal between the living space/engine compartment. Even a small opening will allow a lot of noise to pass. A huge thanks for researching the muffler! Mine's got one, but I suspect it's not the best configuration. Once you selected something I'll be following in your wake! I've also considered a removable pipe extension on top of the stack to move the actual exhaust port up higher and away from the aft deck. Thin wall stainless ducting ought to work. I'll report back if it works. Why all the off-topic comments on the flag? Seems like hyper-vigilance. The boat was a perfect example for the video, and I for one couldn't care a wit about what sort of flag anyone flies from their transom.
Hey Robert. Glad to hear I've got someone to compare notes with! I'm looking forward to talking to Dieselex and seeing what type of muffler(s) they recommend. One thing I should have commented on more in this video is just how much difference sealing the engine room makes to the overall noise - it is only 50% about the exhaust system. Couldn't agree more about Rick's flag - it's his life to live exactly as he choses.
Wow, didn't expect a cleaning video from Dangar Stu.👌😄 7.08.
My experience of 2-stroke engines is that exhausts are purely expansion chambers which do little muffling.
I know there are equations to be worked out in making a petrol expansion chamber, not sure about diesel.
Maybe this is why it was converted, because of the combination of 2-stroke and noise?
I used to drive a Detroit diesel truck in the seventies and it WAS noisy even beside other trucks way back then, when everything was louder.
When I was a scout we had a 50 foot boat with a 671 diesel, it had wet exhaust with side discharge, that exhaust was great fun as it shot a fare size of water about fifteen to twenty feet while underway.
Love the cleanup of your workshop, well done! ;-)
That pair of pliers was driving me nuts!
@@artemiasalina1860 It's not just that he puts it away. The precision with which it snaps into position is priceless! :-)
I'd be happy to have mine that clean!
Good vid Stu.
One other option that a lot of commercial vessels use for a wet exhaust is to run the pipe externally and use it as a sponson.
This is very popular in WA on cray boats.
I like that idea. I think giving anything a double purpose is a really great way to save space on a boat.
Loved the cleanup. I Laughed out loud! Great Job cleaning Up Mate!
I work on steel boats, we cool the exhaust manifold using the pressurised coolant from the engines cooling circuit. Obviously you need a manifold with some sort of water jacket. Also Instead of having pipework on the outside of the boat for keel cooling we just weld tanks to the inside hull. They only need to be 25-35 mm deep but with a large area to allow heat to transfer through the steel hull into the sea. It's simple and works well. Love the videos by the way and I love working on boats.
i would go crazy listening to that metal flap banging on the back
When you been married for a while, you get used to the noise......
I'm a fan of wet exhausts but I think dry is a better option for your boat especially given the space you would gain. Great to hear the reference to Mighty Car Mods... Thanks for presenting a great series of videos while restoring this boat. You keep it real. Cheers, Steve from Mount Gambier
That flap would drive me mad , Steve in Thailand.
yep me too, I would have to stop it clacking all the time.
Ding ding ding ding
@@ReubenHorner 🙉🙉🙉🙉
@Varnce 🤣
I suspect that flap clanking is the result of an engine not running on all cylinders. A Detroit will run in almost any condition. With the amount of smoke coming out on acceleration , this engine needs a tech to diagnose before it starts running away on its' own lube oil. I didn't get a good look, but if it's an 8V-71T, it's about 3 times the engine that boat needs.
Nice explanation, very clear. I have worked on a trawler with a dry exhaust and it was noisey, but there was no muffler, or soundproofing fitted. A steel boat will always be noisier than a wooden one as the wood absorbs sound, while the steel echos and vibrates more.
Filming Dave's boat made me realise just how much of the noise is direct mechanical noise from the engine, something that is only worse in steel. I'll definitely do as much insulating as I can too.
it might be the introvert in me but Im not worried about things being quiet enough to talk. facial expressions are all you need.
1 take out the wet exhaust and putting the dry exhaust back as it makes more sense and gives you more room.. I'm woching all ur videos to day from the start. Verry good videos Ray from England..give usr a shout out ples
Dry just seems safer and more simple. When your out at sea, simple can mean the difference between life and death. Or at least a huge pain in the arse!
It really depends on the boats construction. Dry can start fires in boats and wet leaks,pick the lesser evil for your boats construction.
When I lived near the Chesapeake Bay in Maryland USA, most of the working watermen had dry exhausts. Their lives depended on a safe and reliable boat.
Great hands on Explanation I can see you going back to dry Exhaust And like you said The key Is the muffler Can't wait to see what you come up with
Wow Steve your friend is out and proud of it.
He too old to pretend to be someone he's not.
Dangar Marine well I’ll say we all ought to just be who we are, the world would probably be a lot less trouble filled, I am straight but hats off to the guy for just being himself, btw stu your trawler is awesome sure wish I had something like that down here on the gulf coast of Alabama! Can’t wait to see you underway soon!
Followed you home from Brupeg. Some very important and interesting aspects to consider when restoring maritime real estate to safe and yet economical use and operation. Thanks, enjoyed it.
Really good info here. Nice job ! I no longer have to explain to customers. Just gonna refer them here 👍
I live in the Pacific Northwest of United States. And one of the biggest benefits I think of a dry exhaust with a stack is if you get any type of seasickness not breathing in the diesel fumes really helps.
I had a dry exhaust until I had to have a mass removed from my colon...so more of a wet exhaust now. Can't say I have noticed a noise level difference at all.
Hi there :)
Regarding the detroit diesel... there is no need to remove the turbo chargers.
Remove the aftercooler/aircooler dismantle by taking off all its walls and clean it thoroughly with high pressure wash using something like degreaser or petrol to clear all the carbon soot which has collected within due to the exhaust manifold leak
Stop the exhaust manifold leak and replace the air filters that will stop the smoke
Since its a old detroit diesel the fuel pump on that engine does not have a boost compensator thus the fuel pump is injecting fuel at even though it is not getting enough boost
IF there was a boost compensator with the same issue the engine would not smoke but you won't be able to reach max rpms
In essence the engine is choking
Hope this helps :)
Cool, might give him a hand doing all that and see how it runs.
IF I ever have a wet/dry exhaust conundrum Now I know. 😁🤣Also Stu , you shouldn’t take sooo much time acquiescing to those who say CleanUp! Takes too much valuable time away from your excellent educational boating videos. 😜😁🤣🤣 Keep up the good work! 👍
Thanks mate, I really should have just stuck to writing a "put pliers away" on a post-it note. ;)
Dangar Marine 👍😁🤣🤣
Well Stu, I'm not a marine mechanic but I do deal with diesel engines as a truck driver. My thought is dry exhaust is a better bet. My main reason is that wet involves salt water, steel, and heat and given the corrosive nature of salt alone it looks like a lot of potential trouble with corrosion. That and the dependency on the pump. Dry exhaust going straight up encased in a housing say 5" larger in diameter open at the top and bottom would draw air like a chimney around the exhaust pipe cooling it and providing some natural ventilation in the engine room. Seems like a lot less to go wrong. My thought is go high up with the muffler as your friend did. Should be available in stainless steel and I believe the engine manufacturer should have the spec for optimal back pressure rating for the muffler. Anyway, that's my thoughts on it. Love the videos, I always look forward to the next one! Cheers mate!
I say dry, more space and maintenance possibilities is way higher priority than just noise.
Noise should be secondary to maintenance.
Also build your self a ladder for below deck. Obviously you’ll be doing down there often. Just a few steps should help a ton
You have a real knack for explaining and educating....thank you.
Yes! A Mighty Car mods reference!!!
Was looking for this comment! :D
when
Fin Dennis 15:00
Great video. Having been around car and industrial motors most of my life, don't assume a 4 cylinder industrial diesel will sound softer than a V8. It's totally how the exhaust is designed. Since the previous owner obviously switched to the wet system because he was loosing his hearing standing next to a dry exhaust system, really do your research-find a 471 in your area that has a dry system and check it out! Believe me, they'll be easy to spot.
Good idea leaving the wet system in place until you are satisfied with the dry. There is less possible system failures with the dry. A proper muffler, sound deadening applications should do the trick. Will you be installing a gen set? Also with the stuffing box cooling the shaft nothing changes wet or dry. Looking good brother! I believe your wheel house will be quiet as compared to your friends boat as the engine is under the back deck instead of below the bridge.
Yes, I'm glad the engine bay doesn't open up inside the wheelhouse.
Is there oil in the exhaust because of the two stroke?
@@mastermachineman1462 No. There is no mixing lube oil with fuel on a Detroit diesel. Other 2-strokes use the crankcase area to pressurize the intake air to help push the exhaust out of the cylinders and replace it with fresh air. When this is done it is difficult to use the crankcase area as a lube oil reservoir. This is the reason other 2-strokes mix oil with the fuel, to lubricate the crankshaft, pistons etc. A Detroit does have its' lube oil reservoir in the crankcase and uses an air pump to pressurize the intake air and help push the exhaust out of ports in the lower cylinder walls. You may have seen these pumps before, mounted on the top of old hot rod car engines. They were commonly adapted to use as one of the original super-chargers for gasoline engines!
I share your concern about the reason why it was converted from dry to wet exhaust. But completely agree with your reasons and plan to return to dry.
It's interesting that the chickens appear more prominently in "a day in the life" video than Mrs. Dangar Marine.
She's more camera shy.
The effort to put this very informative video is appreciated and applauded. Learned a lot and look forward to all the many steps left in your project.
chop the lot out, use a flexi pipe up to deck head, then across to the side, and down to exit just above the water line , if need be you can use a rubber muffler outside to lesson noise and stop any backwash......... I have noticed with Stack Pipes if they are not high enough you get a back swirl of exhaust in the after deck when going forward, but a canopy could remedy it........... good luck with the project I have done a few of them mostly on wooden boats......cheers UK..
Yes, I can see how the vacuum behind the wheelhouse could draw the exhaust fumes back down. My big worry is that I go back to dry and then go, ah, that's why they got rid of it. ;)
Dangar Marine how easily can you test it?
If you don't have a DPF on the dry exhaust of an old diesel you will be raining down some VERY toxic chemicals on anyone downwind. Also, judging noise level of an engine at idle is like judging the speed of a horse on a lead rope :-) Enjoying the story Stu - great stuff.
can certainly see the huge benefit to dry in your situation. seems like a no brainier
Those Detroits sure are quiet. Ive worked around plenty on trucks, marine and industrial and love the sound.
Good video by the way.
Sick 2 vids in a week 👍👍
All sort of stupid conversions have been done to my boat by the second owner. The guy who build it know what he was doing. I would really like to convert it back to dry and go back to 24V instead of the 12V I have now. Hope you will go for the dry exhaust. 4-71's are sweet. I could listen to them all day with a good muffler. Wet exhaust is just like some one is puking at the back all the time :-)
I'm definitely thinking I will at least try dry. I'm always going to be wondering otherwise...
Very informative Stu...thanks for the vid and great to see a couple of classic Detroit Diesels purring ...what a great sound. I'm thinking Brupeg has a dry stack ??
Thanks Mark. Yep, Brupeg has a dry stack and keel cooling.
Absolutely loved the ‘cleanup’ nearly fell out of my chair laughing, keep up the awesome work Stu!
Dry exhaust system seems to have advantages over the wet exhaust, below deck space and pump fail seem to be a disadvantage for the wet exhausts system. Nice upload today very interesting but a bit to short. I can watch your boat escapades for hours, looking forward to your next upload. Regards from a uk land lubber pom😊
Thanks mate, glad you enjoyed it. :)
I know nothing about boats but loving this series your clean up was brilliant pissing my self can't wait for the next installment Thank you for the vids
I laughed so hard when you "cleaned" up your workshop. When they are renovating a steel boat, they can comment.
😂😂😂me too
Which ever you choose...Iam still very happy to watch your videos every week :-)
Thanks mate!
Having run quite a few boats with Detroit’s you can’t have enough sound insulation on a Them. No matter what you do make sure you have a considerable amount of insulation and a well designed muffler.
I had always read the speedboats and stuff have to do it for cooling, interesting to hear all the pros and cons stacked like this. Good stuff stu!
turbo detroits are a lot quieter than a naturally aspirated detroit so don't expect your 471na with wet exhaust to be as quiet as your mate's 8v71ta!
Go for the Dry exhaust mate. Love watching what u do
Looking good with the flag waving behind you. Don’t really know much about boats but enjoy watching you fix em for sure.
Great vid Stu. I've seen some wet exhaust boats with the outlets at the stern but opening out either side rather than the transom. I realize now the point probably is to combat the fume issues in the following sea/wind situation by ejecting exhaust out and away from the boat.
Hi mate...keep up the great work, your vids are awesome and cannot wait till the next instalment ....can't believe I'm getting excited about wet or dry exhausts 😂
Watch your vids all the time and actually lived just where you are.
From experience, please keep the wet exhaust if you are contemplating long voyages as a dry will drive you nuts!
The constant and pounding Lulululul will make you want to want to get back to shore even faster, thus slapping the piss out of blue water cruising.
Thats if thats your intention with this boat of course.
Great vids!
thanks for sharing!
That is my intention with this boat, but I'm not sure I would do that with the original Detroit Diesel, I think it would bankrupt me!
Great job with the shop clean up. Love the flag on your mates boat.🏳️🌈
Thanks mate!
Wet exhaust design: The exhaust pipe from the turbo or manifold should be water jacketed until it falls at least a foot towards the exhaust outlet. Sea water cooling from the heat exchange enters at the top of the jacket and exits through a water curtain into the exhaust pipe. The water curtain should allow a one or two PSI back pressure in the water jacket to maintain complete cooling. In my boat I have a low pressure water gauge installed in the sea water cooling system. It's the water jacket and cooling water which silences the exhaust. Gauges installed for my boat engine: coolant, oil pressure, turbo boost, tachometer, heat exchange sea water pressure and engine hour gauge. All these are necessary to monitor the engine performance and maintenance, running hours between oil change, etc. I hope this helps. Cheers Chris.
Nice design with the jacket before entering the exhaust pipe and yes, couldn't agree more about having all the right gauges and having them working.
Go with the dry it suite your stile of boat
A kenworth muffler will fit that motor
I think going back to a dry exhaust would be great! I’d just improve the muffling and insulation and then you’ll be set! Maintenance space is so helpful!
I've owned several trawlers and sailboats all with wet exhaust. Even though you can cover a dry exhaust pipe it will still put out a lot of heat that will collect in the engine room. You will not be happy with that. Other systems will be affected by the heat. If you simply redesigned the wet exhaust to use space more efficiently you would have the best of both worlds.
I have owned and operated both wet and dry exhaust vessels. The dangers of a wet exhaust are:
(A) going hard astern, where the sea washes back into the turbochargers, Particularly vulnerable craft are low slung speedboats. No room for a high-rise bend in the exhaust pipe before overboard skin fitting.
(B) Heavy rain or leaky stern glands; especially low slung powerboats unattended at moorings or marina dock.
These can cause entry of seawater into exhaust manifold and cylinders; wrecking the entire engine. As a boatyard proprietor I have had various customers with these problems.
A dry exhaust with a large muffler (exhaust silencer) is the best, hands down. Raw cooling water appearing from skin fittings above the waterline then confirms that the heat exchanger is being supplied and no other possibility.
As far as occupying space is concerned; no reason dictates funnel must be amidships. Awnings, Radar and antennae goalposts aft can carry exhaust pipes on either side.
I'm happy with my decision to go dry, it has certainly given me a lot of room back in both the lazarette and engine bay.
I sure wish I was living in Australia.
Thats so cool
Come visit!
@@DangarMarine Settle this once and for all.
Is it true toilets flush counterclockwise down under???? 🤭😬😉
Just for your info my father in law had a 52' Riviera with twin 400hp Detroits. Both motors were wet exhausts. When the boat was just cruising the motor noise was to the point, both inside and outside, very noisy. This was even though the engine bay under the rear floor was soundproofed. Also if you got a tailing wind the fumes coming from the twin rear wet exhausts was fairly powerful on the rear deck area causing us to have to go inside and close the rear door..unless the front hatch lids were opened but that was not possible in heavier seas.
I have been on boats with stacked dry exhausts and they are quite different in that it does seem quieter and the fume problems were also a lot less depending on winds.
Also access to both engines was extremely difficult, as you've pointed out, for maintenance on the Riviera because of the exhaust system.
Just thought I'd put my two bobs worth on here. 😁🇦🇺👍🏻
Sounds like another vote for dry!
I would definitely go with dry exhaust.
When you do your dry exhaust I know everyone loves a nice shinny stainless exhaust but I would really recommend doin a black ceramic coating on it after it’s all been made and fitted will also help with the radiating heat and also big part help agains corrosion even tho it will be stainless the heat cycle through it will allow it to start and then after that in the engine bay still heat wrap it aswell but I wouldn’t heat wrap straight to the mild steel section in engine bay cause it will still corrode and ends up cooking the exhaust and makes it prone to fatigue and cracks,
Pro Coat at Wyong are reasonably priced and do a great job had my rear turbo housing and manifold done by them,
I’m local to somersby would love to come check out this awesome project and maybe volunteer some of my time and ideas
Keep up the great work !!
In your boat Stu go with the dry. Less issues and your boat is already set up for it.
I end up removing other's upgrades on every boat I touch so don't worry about that..
I'd definitely go back to the dry exhaust, too. That freed up space below deck is too good not to take advantage of. And less holes in the hull is always a good thing. I'd invest in a good quality one like your mate had. Silence is golden.
Project Brupeg has a keel cooling system like you described.
They do, but they are thinking of removing it before getting to the ice fields.
the shop clean up was Fantastic. Keep up the important work.
The Orka had a dry exhaust and it took out Jaws!!!
Jaws ain’t bitchin with this transom😟
but sunk in the process...
My kind of clean-up, Stu. I vote dry exhaust, too, BTW, even though my 48 foot wooden bird has a wet exhaust. The only reason I don't change it either is because it works fine, and it would be too much work to change over. If I was restoring about like yours though, and I had a choice, it would be dry exhaust and keel cooling for sure. Any through-hulls that you can eliminate has to be considered a positive.
You Aussies like your beer. Not that that's a bad thing...!
We Dutch too
I don’t like the idea of a dry exhaust but your space issues make it a really good idea
go dry you won't be sorry. I have thrty years engineering fishing boats in Alaska. leave lots of air space in your stack!!!!
heat rises. put a big blower to force air into engine room from out side. wrap all pipe well use as much sound deadener as you can afford
nortin1o One good thing about wet exhaust is that most of the exhaust noise leaves the deck
howdy mate, We switched from wet exhaust to dry on our small push boat for our dredging business. It worked out much better.one less sea strainer and pump to worry about.
That's good to hear. :)
I would be willing to bet that heat was the reason for converting to a wet exhaust system. The engine may well have keen running too hot.
Best cleanup ever! Put the naysayers where they belong. Great video. Been around boats my whole life, fresh water, salt water, etc. Love your take on things. Keep 'em coming.
Thanks David!
Go dry, wasn't keen on the idea until Dave started his trawler.
Plus one for the dry option, I feel its much more suited to your situation. It wouldn't surprise me if the last guy converted it to wet exhaust based on hopes and long standing feelings about this subject as some are staunch believers in one or the other.
Don't worry about the mess.
"The space efficiency of pure chaos is hard to beat!" - Matthias Wandel
Another thing to consider in the wet exhaust system, is that if the water is injected into the exhaust at or close to the water line, a siphon break is a good idea to install in the raw water discharge line with a loop above any possible water line. This ensures no water can siphon past the raw water pump and fill the exhaust.
This is done primarily in sailboats and other vessels where the engine is below the waterline.