What is the fastest board shape for flat out, flat water speed? The needle?

Here's my take.
It's mainly in the tail, the rest of the board is just there to get you started. It's all down to minimum wetted area and efficiency. a long narrow wetted area is low aspect ratio and will have more drag as a consequence, but as speed increases, and the point of entry moves back it can have less wetted area than a shorter wider wetted area, which will have less drag initially, but is restricted in how small the wetted area can get. So the needle has the potential to be faster if it's fully powered.

As always....depends.
Perfectly powered and beam reaching, the narrowest you can sail. For me, 15" and 18cm wide base speed fin.
Add an upwind component, maybe up to 65cm wide with a 43cm tail and 38cm fin.

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gollyone said..
What is the fastest board shape for flat out, flat water speed? The needle?

Narrow is fast! Wide means drag! But I am not so sure if modern speed boards would qualify as needles. They are much shorter than they used to be. My venerable (2008) CA slalom 52 wide, with a tail that is 32 cm wide one foot off, has very similar numbers to the Patrik Speed 53, but it is 14 cm longer .. much more needlely than the Patrik.

It is, by the way, the only board on which I can go faster than people 40 pounds heavier than me in overpowered conditions, and I clocked a few 36-37 knots with it in less than ideal conditions. Of course the problem is that if the wind drops ... you are dead, while a wider board would keep going.

Ideally, on a non-foiling board, riding on a fin would deliver optimum speed because there would be no surface to surface friction from a board being completely out of the water. The only board I've found that allows for a purely fin ride is the Mistral Diamond Head provided it is equipped with a 32cm trapezoid skeg.

It pretty clear that, for whatever technical reasons, narrow boards around 37-45cm at wide point (Current typical small speed boards), are what is being used to set the fastest speeds at most high end speed venues such as Luderitz canal etc. So for broad reaching in very strong winds and flattish water, these are the current optimum.

The current speed board shapes are more of a rounded or squashed pin tail than the earlier 'needle' types which were very pointy. Newer speed boards have wider 'one foot off' measurement. The bottom shapes are quite flat. If they have vee and/or concave, those things are typically, quite subtle. The foot strap and mast track positions are also a lot further rearward than on the earlier speed needle types of boards pre 2000's.

It is also pretty clear that modern smaller slalom/larger speed boards in the 48cm to 65cm wide range are regularly being used to crack 40 knots in more real world, less than ideal conditions. By that I mean winds in the 25-30 knots range and usually on flattish water, but not always.

Some bigger guys are cracking 40 knots on even larger/wider modern slalom boards, but this seems to be more restricted to the big guys.

If you are talking about beam reaching, as distinct from broad reaching, the speed advantage of narrower boards is less distinct and seems even more dependant on wind strength, water state and sailor body size.

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duzzi said..

gollyone said..
What is the fastest board shape for flat out, flat water speed? The needle?

Narrow is fast! Wide means drag! But I am not so sure if modern speed boards would qualify as needles. They are much shorter than they used to be. My venerable (2008) CA slalom 52 wide, with a tail that is 32 cm wide one foot off, has very similar numbers to the Patrik Speed 53, but it is 14 cm longer .. much more needlely than the Patrik.

It is, by the way, the only board on which I can go faster than people 40 pounds heavier than me in overpowered conditions, and I clocked a few 36-37 knots with it in less than ideal conditions. Of course the problem is that if the wind drops ... you are dead, while a wider board would keep going.

Love my 52 too, got a replacement coming soon 56 wide with a pulled in tail. Find some flat water and that 37 will seem slow. The boards good for over 40 and if you get it right that's just the start. A very versatile board that will never leave my kit

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kato said..

duzzi said..

gollyone said..
What is the fastest board shape for flat out, flat water speed? The needle?

Narrow is fast! Wide means drag! But I am not so sure if modern speed boards would qualify as needles. They are much shorter than they used to be. My venerable (2008) CA slalom 52 wide, with a tail that is 32 cm wide one foot off, has very similar numbers to the Patrik Speed 53, but it is 14 cm longer .. much more needlely than the Patrik.

It is, by the way, the only board on which I can go faster than people 40 pounds heavier than me in overpowered conditions, and I clocked a few 36-37 knots with it in less than ideal conditions. Of course the problem is that if the wind drops ... you are dead, while a wider board would keep going.

Love my 52 too, got a replacement coming soon 56 wide with a pulled in tail. Find some flat water and that 37 will seem slow. The boards good for over 40 and if you get it right that's just the start. A very versatile board that will never leave my kit

I know 36-37 is slow!! but there is no flat water in the Bay Area! The second you cross 18 knots of wind or less the chop is there ... what I need is 40 more pounds (and 10 less years of age!).

boards.co.uk/how-to/how-fast-can-we-go-the-science-of-speed.html
A good read re speed.

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kato said..

duzzi said..

gollyone said..
What is the fastest board shape for flat out, flat water speed? The needle?

Narrow is fast! Wide means drag! But I am not so sure if modern speed boards would qualify as needles. They are much shorter than they used to be. My venerable (2008) CA slalom 52 wide, with a tail that is 32 cm wide one foot off, has very similar numbers to the Patrik Speed 53, but it is 14 cm longer .. much more needlely than the Patrik.

It is, by the way, the only board on which I can go faster than people 40 pounds heavier than me in overpowered conditions, and I clocked a few 36-37 knots with it in less than ideal conditions. Of course the problem is that if the wind drops ... you are dead, while a wider board would keep going.

Love my 52 too, got a replacement coming soon 56 wide with a pulled in tail. Find some flat water and that 37 will seem slow. The boards good for over 40 and if you get it right that's just the start. A very versatile board that will never leave my kit

+1 on the CA52 fan club. A great versatile board for all GPSTC categories. Actually, all my PBs are on that board except 2S and 5x10 (CA47)

Gunnar says wide is fast !!
www.facebook.com/gunnar.asmussen/videos/10158751884662708/
40knts with an 85 wide and 8.6 sail LOOL this must be intense !

so does slowboat
watching him wound up on his 137 mistral
makes me realise what a crap sailor I am.