How To Build A Sailing Boat #1 - My Catamaran Hull Design Explained - Ep03
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- Опубликовано: 5 авг 2024
- Here’s a short explainer on sailing catamaran hull design and the theory behind our own hulls.
We have a quite distinctive and unusual design for a high performance cruising catamaran, and Laurence does his best here to guide you through the thinking behind them.
This is definitely one for anyone who's ever wondered how to start designing and building your own boat.
Timecode
0:00 Intro with stills
0:16 Choosing a designer
1:02 Deciding on hull length
2:18 Low aspect keels or daggerboards?
3:29 Narrow waterlines
4:51 Theory of wave drag
5:11 Hull displacement vs slim fast hulls
6:13 The advantages of a double-ended hull
8:13 Using a chine for accommodation
9:54 Summary of hull design
Thanks for watching!
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You are not a naval architect but prolly a brilliant salesman or a lecturer! I am Sold!
Excellent video, Thank you sir. Btw I'm a Mechanical Engineer from TN, India
This was one of the best explanation about hull designs I’ve ever listened too. Excellent
Thanks! So glad you enjoyed it :)
I'm echoing the previous comment. Fantatsic description of the advantages and purpose of the design. Thank you for sharing.
I can't wait for the next installment.
So glad you enjoyed it!
I have an idea that will get millions of views. Lawrence once gave me the single best description of speed against height when sailing upwind that I have ever heard, he even drew a graph, I have tried to recount it to hundreds of people since he told it to me but a video I could direct them too would be amazing. I suspect it would be of interest to almost all fast boat sailors! I don’t remember the finer details but do remember that the difference between 55° and 60° was shockingly significant. Helped me do well in a lot of races on a lot of boats! 🙏
Thanks Andy! Glad it was useful info and that you've been racing well :)
Beautiful explanation. Thanks
Thanks very much! Glad you enjoyed it :)
Very impressive boat! I would love to see more about the mast and the rigging in future updates. And some sailing too! Thanks
Coming up soon! It's winter here at the moment :(
Respect to your original and efficient conception and réalisation. Well explain. I think that you have a lot of pleisure with it. Thé help of your neighbourgs is very warm. Bravo 👍👍👍.
Un petit bonjour de Lyon.
Merci beaucoup!
Superb explanation as to your thought processes & simple to understand, congratulations!
You’ve created what appears to be a functional and attractive boat & I look forward to seeing footage of her underway - will definitely be following along for future updates.
Thanks for the feedback and glad you are enjoying the films!
Great explanation!! Thanks for sharing!!
No worries! Glad you enjoyed it :)
Super cool. Thanks!
Thank you :)
Great design lesson. Thanks.
Glad you enjoyed it :)
Nice choice of hull lines designer !
Yup limited load carrying but speed too! Love it ! Cheers Warren
Thanks Warren!
Beautiful hull shape.The integrated rudders and the tapered stern - awesome
Thank you! :)
Superb informative video - thankyou
Thanks so much for the feedback! Really appreciate it - Keep an eye out for more coming soon :)
Thanks for the information on hull design. :)
No worries! Happy to share :) and thanks for watching!
@@SailingWildHoney I was looking at Wharram cats because of their simple designs. I like the Tiki 38 and 46. I like the fact that they can be beached but I would want more shade on the deck. I don't know if I want to build one or buy one that needs some work. Probably a few years out anyway. Subbed to your channel. :)
Thanks very much! Hopefully the channel will give you some good ideas of the pros and cons of various features :)
Great information. Great to hear the logic for the shape. The boat hulls look sleak and fast with brilliant shallow draft.
Thanks!
Love it
Thanks! :)
I wanna build mine!! please post more details how you build the mast!
Planning a feature on it in the future :)
Brilliant film again you guys, you explain things so very well, maybe a tv channel should do a feature on you both and your experience of building your own Cat, great work, miss you guys, Xxx Simon
Miss you too! Thanks for the lovely feedback! Xxx
RUclips is the new TV.
Beautifull boat! The hull design and the general boat structure make ne think a lot of the Dazcat.
Thanks!
I love Dazcat.
I don't love the price.
You are absolutely right....that hull shape is very similar to Dazcat Cloud 9 which is 39 feet. Modern Dazcats are not canoe hulls so much but C9 is.
Have been the proud owner of Cloud 9 for over 20 years....original owner had her built in 1995. Wonderful boat....it will last a lot longer than I will!
A really interesting set of videos for anyone contemplating buying a catamaran, and especially building one.
I have a 1988 Catana 40 that has a design displacement of 5.4 tonnes .... probably around 6 tonnes now due to all my gear, inboard diesels. My guess is that yours must be considerably lighter .... 3.5 to 4 tonnes?
I've owned mine since 2008 .... circumnavigating and investigating many parts of the world ... and with many left to explore. It has really excellent sailing characteristics ..... as I'm sure yours does.
Good luck on your adventures.
Thanks so much for the feedback. Sounds like you've had some great adventures, with more to come! :)
Hi, do you have any comment on pitching effects with a fine entry and exit double ender? How does Wild Honey handle waves? Naval architects typically favour more asymmetry with fine entry and fatter/flatter sterns to damp pitching oscillation. I guess to an extent the horizonal rudder foils damp pitching...
Superb explanations. Thanks mate!
The narrow hulls at the waterline are shaped like a keel, and should counter leeway through lift generated by angle of attack.
The rudders are almost like a trim tab at the back of a wing, and are very different from the high aspect ratio rudders and keels found on most boats, BUT, a correctly trimmed boat should not need much rudder AND is more efficient. I do wonder if they have enough authority when going upwind, but the daggerboards should be doing most of the work then, and again the sails can (and should) be trimmed to do most of the steering, ideally with minimal rudder use. One of my sailing instructors called the rudder the parking brake.
Thanks very much for the feedback - yes, I think you're quite right in everything you say. And in fact she could sail quite well, even without the daggerboards. But she does sport small daggerboards inside the rudders to help.
@@SailingWildHoney Interesting, so there are daggerboards acting as small high aspect rudders inside the rudders for better authority if needed.
In principle, deep downwind, no boards and not much rudder would be needed most of the time.
Great explanation. I've so often wondered why we don't see more catamaran hulls with pointed sterns. Much like Wharram.
I look forward to more videos explaining the performance. I would also like to know a bit about the specs and dimensions.
Thanks! That's an interesting idea - we've got lots more details coming in future films :)
They used to design cats with narrow sterns like the early Outremers. Obviously the naval architects decided a wider stern was preferable so that's pretty much what is done now.
…hobbyhorsing
Not only uncomfortable, but knocks the air out of your sails, as well as problems for your outboard
When I bought my cat she had sat on a Sandy beach unused for a number of years. I never got to inspect the low aspect keels, not until I got her back home did I find that the lower half was still in the sand on the beach!
So she will now get centreboards.
A short skeg for grounding is perhaps a good idea, to protect from rock, though that means you can’t so readily drag her up the beach on rollers.
@@laurapitre5797 I’ve always found it amusing how design details follow a circular path - think of the Moody yachts from the 70’s with their incredibly broad transoms to create voluminous aft cabins so that they were ‘comfortable for the wife’ (their London Boat Show marketing!). A dreadful case of form following function; they were horrendous going upwind.
Very good explanation! What is the waterline beam of Wild Honeys hulls?
Pleased you enjoyed it. She's approx 550mm on the widest part of the waterline :)
Impressive! More than 20/1 L/B ratio, you must get pretty high speeds? Even under power do you achieve higher than hull speed? THX
@@SailingWildHoney
Hull designs depends on a number of components.
Volume required ie a double bed in the hull or single.
Weight of the yacht and all its required to carry.
Eg if a yachts total weight is 6 tons then each hull neefs to support 3 tons.. this can be a rectangle prism ie 3 m long 1 metre wide 1 metre deep. Wont sail to well but will float. So your hull needs 3 cubic metre of boyancy.
Shape is an art to get the best performance
Nice and simply put! :)
Hi. Im in South Africa. What is the possibility of getting a set of plans?
Hi there! Plans for this design aren't currently available, she's a true One Of A Kind! :)
With the narrow stern do you have issues with hobby horsing ?
That's something we're going to cover in a future video, but most catamarans suffer a bit in certain conditions. Long thin hulls can be more prone though :)
You say you got the designer to draw the lines, but how do you get all the structural requirements (bulkheads strength, mast stay, joinery etc) figured out?
Thanks for the question! The designer also gave us some calculations for the main cross beams and the rest we worked out from our own knowledge base and similar custom race boats that we knew about. There were also 2 similar sized cats being built in this art of the world and we compared specs and ideas to check we were in the right ball park.
Have you ever looked at the MaineCat 38 ? Its a light sport cruising cat.
I know that part of the world of old.🧙♂️🇬🇧😎 One of my favourite modern cat
Designs is the Windelo Built in Basalt but Im also a fan of the later Wharrams and have been a long term follower of Mark ..of Wilding sailing .
He has a 42' pahi he rescued and is trying to build up in Holland.
The Hitchhiker series of boats incorporate many of the hull features of your hulls but carry the aspect ratio to the extreme... they offer no living space within the hulls on the later versions.
Being a multihull enthusiast Laurence knows all the boats you mentioned there. And he's also watched a fair bit of Wildling Sailing. We feel Wild Honey offers a good compromise between performance and accommodation :)
How wide is the hull at the widest waterline?
Thanks for the question - she's approx 550mm at the widest waterline
Are those drawings available. I’d love to have digital copies
Unfortunately not, I'm sorry to say
I didn't notice any kind of fins or boards. What is this boat using?
We have daggerboards, which we may do a feature on as they don't come through the deck like conventional ones :)
@@SailingWildHoney aha James Bond 007 style, thank you, would like to see them.
How old were you when you first made a decision to build a cat?
I'm kind of in the same place right now, I'm almost 29 now, the plan is to build a simple 10m boat first to figure out all the technological processes and material and then build shonning 1200
Thanks for getting in touch! Sounds like you've got an interesting plan. I reckon I was about 16 when I first started dreaming of my own boat. I was a boatbuilder before I started on my own boat, so was aware of what I was getting into. Even so it took a lot longer than I expected! A lot of the time it was just the two of us, or me on my own. Luckily I had a healthy level of self delusion as the launch date kept getting postponed! I would be tempted to just go for the Shoinning 1200 and forget about the 10m as building a boat is a big project. If you want to test some ideas, build a tender which you can use on the big boat. Hope this helps you out.
Piro, in which country will you build your boat?
@@CorvetteCarCraft i almost certain that i won't do it in Russia, here you need to pay 50% tax of all money you spent on the build.
I think Thailand, Malaysia, Portugal or Georgia
@@pironiero Interesting. I'm in the same situation (Belgium highest tax of Europe). My build will be in Thailand. Maybe we keep in touch?
@@CorvetteCarCraft sure thing
Aw3some info. I have an early Nic Bailey designed Catamaran. She weighs around 4 tonnes but her performance to windward ain't great as the hull shape ain't great like a u. Been speculating how I could change this. Was thinking I could vac on some airex to the bottom to make more of a v. Hard to comment without seeing the boat I guess
Yeah, really hard to know without seeing your boat, but maybe look at the easier solutions first - daggerboards and rig both play an important role in your upwind capabilities :)
Small boat, small problems.
Felt pretty big when I was sanding it! :-D