Michael, I'm a Yacht Engineering Student and Paddlesurf practicioner, I've always been fascinated by the design and the evolution of raceboard shapes. Do you guys do any CFD/FEA testing when you design your boards? or is ist just based on pure testing - reshape -testing? I would assume computer simulations assume a too perfect of a scenario for these craft...
I often ask the same question as a small craft design enthusiast and race sup paddler! I've never heard of a sup board design ever even being loaded up with the appropriate rider weight and put in a towing tank, which I would think would be the first stage, and quite cheap to do. Last time I spoke to a naval architect about this about 5 years ago, the CFD programs at the time could not cope with periodic pulses of propulsion, such as rowing or paddling. They were only designed for constant thrust from an engine, or sails, or electric motor and also a static payload that stays in the same position fore and aft not shunting up and down the board. This limits the software when it comes to optimizing sups, but I'd have thought it would be worth a try. If nothing else, you'd get some nice CFD streamline drawings to put in the next board brochure. If you start by designing to limit the drag on the board being towed at a constant speed with a spring balance, that's a much better starting point than manufacturers seem to currently have. One BIG problem all sup boards seem to have is squat or suck at the stern, ( the harder the athlete paddles, the more the stern sinks and the bigger the stern wave and energy wastage gets, (and the better they are to draft) without getting much faster, unless your athlete can somehow find another 3 hp from somewhere and get it on the plane). It's a problem that all displacement hulls have had since Noah's ark, but you never hear the manufacturers speak about this or how they are designing around this, which suggests they may have not yet got that far up the road. Instead they upturn a board and talk in over simplified terms about how the water would 'flow over' it, as if it was being fired down the board as a sheet of water from a flat ended hose. Which it emphatically isn't. Flat water Sup boards have evolved from surfboards and windsurfing kit, both of which can properly plane, the former due to the kinetic energy of the wave, the latter from approximately 6hp worth of wind. They both have ample power to 'get over the hump' so the fact that their hull is least efficient just before they do is a non problem. A racing sup, whether it's a 2020 starboard sprint or anything else sits at that very steepest point of the energy in / speed out curve, spending most of its energy creating a great big hump of water, that in flat water, no paddler in the world will ever get close to producing enough power to get the board to climb over. This is what makes racing sup boards very interesting from a naval architectural point of view, and findings made in that difficult transition zone at the top end of displacement speed and the bottom of planing speed (that most powered vessels simply avoid spending time in, so few people research) could have value elsewhere in naval architecture. As a yacht engineering student, you should look into doing some sup optimization projects! There are potentially some interesting, worthwhile, and I think initially quite easy discoveries to be made in race sups!
Michael, I'm a Yacht Engineering Student and Paddlesurf practicioner, I've always been fascinated by the design and the evolution of raceboard shapes. Do you guys do any CFD/FEA testing when you design your boards? or is ist just based on pure testing - reshape -testing? I would assume computer simulations assume a too perfect of a scenario for these craft...
I often ask the same question as a small craft design enthusiast and race sup paddler! I've never heard of a sup board design ever even being loaded up with the appropriate rider weight and put in a towing tank, which I would think would be the first stage, and quite cheap to do. Last time I spoke to a naval architect about this about 5 years ago, the CFD programs at the time could not cope with periodic pulses of propulsion, such as rowing or paddling. They were only designed for constant thrust from an engine, or sails, or electric motor and also a static payload that stays in the same position fore and aft not shunting up and down the board. This limits the software when it comes to optimizing sups, but I'd have thought it would be worth a try. If nothing else, you'd get some nice CFD streamline drawings to put in the next board brochure. If you start by designing to limit the drag on the board being towed at a constant speed with a spring balance, that's a much better starting point than manufacturers seem to currently have.
One BIG problem all sup boards seem to have is squat or suck at the stern, ( the harder the athlete paddles, the more the stern sinks and the bigger the stern wave and energy wastage gets, (and the better they are to draft) without getting much faster, unless your athlete can somehow find another 3 hp from somewhere and get it on the plane). It's a problem that all displacement hulls have had since Noah's ark, but you never hear the manufacturers speak about this or how they are designing around this, which suggests they may have not yet got that far up the road. Instead they upturn a board and talk in over simplified terms about how the water would 'flow over' it, as if it was being fired down the board as a sheet of water from a flat ended hose. Which it emphatically isn't.
Flat water Sup boards have evolved from surfboards and windsurfing kit, both of which can properly plane, the former due to the kinetic energy of the wave, the latter from approximately 6hp worth of wind. They both have ample power to 'get over the hump' so the fact that their hull is least efficient just before they do is a non problem. A racing sup, whether it's a 2020 starboard sprint or anything else sits at that very steepest point of the energy in / speed out curve, spending most of its energy creating a great big hump of water, that in flat water, no paddler in the world will ever get close to producing enough power to get the board to climb over.
This is what makes racing sup boards very interesting from a naval architectural point of view, and findings made in that difficult transition zone at the top end of displacement speed and the bottom of planing speed (that most powered vessels simply avoid spending time in, so few people research) could have value elsewhere in naval architecture. As a yacht engineering student, you should look into doing some sup optimization projects! There are potentially some interesting, worthwhile, and I think initially quite easy discoveries to be made in race sups!