No surf so I thought I might compare board paddle speeds.
I paddled on flat water, over a distance of 100 meters or so, watching the GPS I have the following numbers.
It is a bit rough doing it this way because a GPS is sensitve to board surges as I paddle, this was more evident on the shorter lighter boards.

To do a really accurate assesment a GPS could be set with 2 way points then read off the VMG. Velocity made good to the waypoint, that would then show a true picture how a board paddles to the takeoff zone, or point B.

It would take into account board yaw & the higher number of paddle changes on the short boards to try & keep them going in the right direction.
A short board getting to point B covers more distance because of the greater yaw, & at a slower speed, short board speeds or VMG, would be actualy slower than the numbers below. in k's

14'x27" .......... 8 cruise, 11 max

9'4"x28".......... 7.1 cruise, 7.7 max

8'2"x30.5"....... 6.5 cruise, 7.2 max

7'10"x30.75".... 6.2 cruise, 6.8 max

7'10"x27"........ 5.5 cruise, 6 max



How do you think this French thing would paddle?

Interesting numbers LSD .is the reason the 7/10x30 is faster than the 7/10 x27 a volume issue ,that is the 7/10x 27 is sinking . Also interesting to see the difference in cruise speed and top speed is accentuated the longer the board . I've noticed this on my 9/6 . I can cruise along all day putting in easy strokes , but going 20% faster takes 80% more effort until top speed and it doesn't matter how much effort i put in after that . I guess that's just the physics of hull speed .

Love your enthuisiasm for baord design LSD , your distance boards look really fast.

There would be a point where the length of the board wouldn't increase speed any more. I don't think a 20' board would be any faster than a 16' board made from the same material. But I build websites not boats.

Oliver,
Would you care to make a small wager on that?

There would be a point that longer wouldn't be faster but I don't think that point is 16ft.

Length means weight but weight would help momentum. Tricky trade off I would think.
On flat water extra length would be very important but once it gets bumpy finding a shorter optimum length would be hard.

For displacement hulls the speed is directly proportional to length. There are formulas for calculating the speed for a given hull length.

The only problem is the formulas assume the provision of adequate power. All you need to do is throw up a tall enough mast and big enough sail, or big enough diesel, or enough burly rowers.

SUPs have only one-person-power so there will be a point of diminishing returns where a super long board will weigh too much for one person to push along.

Sea kayaks come up to around 24' so I'm guessing that would probably be the upper limit for a practical racing SUP.

Actualy guys

You would find a child on a 20' or 24' SUB for that matter, could paddle faster than you on a 7' 10" SUB.

Suppose you will like me to prove it hey...........give me time to make the board & you can pilot it yourself.

your've missed some very important points