I have an 85L Sonic which I sail comfortably in 16 - 23 knots but above that it requires a lot of legwork and effort to keep it down in the river chop.
Given that I only weigh 58 kg what size speed/slalom board should I look for for high wind days (assuming we ever get any again - ever the optimist!) to go with 4.7 and 4.9 sails?

This is a very good question.The problem to me is not so much the size of the board, but the fact that slalom or speed type boards just go faster and faster as the wind strength goes up. The inherent issues there are control and comfort, even on a smaller board.

I have found it very difficult to sail on a slalom board in winds over low 20's wind on an open lake with short confused wind chop. Curiously, it is actually a bit easier sometimes on open ocean as the waves tend to be larger but more even.
Even so it is not easy. It seems very frantic and energy draining.
On my local lake in 25 knots I can only last about 15 minutes and I am pretty well stuffed. It is not just the physical energy, but also the mental stress of concentrating on not coming to grief.

My solutions in the past have been twofold:

The first is the faster ride. I have had a couple of custom Polyester/Fiberglass slalom/freeride type boards that have worked very well in those conditions. A little bit smaller than my IS87 slalom board at 8'4" X 18.5" and 8'6" x 20.5" but still a fast, flat rocker like. The big difference was the construction material. The polyester boards ride a lot smoother, less 'harsh' than epoxy boards. They seem to absorb the worst harshness and allow for a more relaxed and controlled ride. This is still only good for me up to about high 20's though. The best of them was the larger, a single stringer glassed fairly light. I think this allowed more dampening effect but unfortunately it also allowed it to be pounded out of shape a lot faster. I still have it and plan to do some major repairs so I can use it some more. It is a lot of fun.

Over 25kts, the second solution kicks in: The 74 litre wave board. The wave board is slower in rough water. The rocker line helps keep the speed down to a controllable level. Less speed equals a softer and less frantic ride. Works for me........

I have a 74 L waveboard. For sure it is much easier to sail in chop when it is windy but I want something faster...

Slalom boards I view in terms of width as a 10l in volume difference is minimal. I use 78, 69, 59, 54 (cm wide)...the 54 coming out in high 20's, 59 as soon as I can in low 20's, 69 for long distance and high teens and 78 for low teens.
These equate to apx 130l, 110l, 90/95l, 75/80l. You weight is considerably less than mine so could easily shift down a size with 49-54-59-65.

For flat out speed I have a 49 but its no good for the salty lake we sail on, which is very choppy most of the time in every direction, SSW having a short flat run and SW having a broad reach that turns into death chop very quickly.

As sailquick said this is a good question..
There is a point where too small a board will deliver diminishing returns In the scenario you describe imo.
A large board generally requires a large fin and the combo of both will fly off chop with ease.

The problem with a smaller board means the need for a smaller fin..this creates issues in chop as you know..the fin tends to come out of the water more often meaning i greater chance of sliding and catching a rail.The smaller board can also be just as flighty in the air as a bigger board,with perhaps less margin in error in respect to controlling the board.

Your comments re a lot of leg work may mean you are using too much fin?

Knowing you- i reckon a slalom board around the 74ltr mark with lots of v and double concaves in the pointy end would be a reasonable solution..a board such as a manta 54.

This is the exact reason i ride Exocet Cross boards, I find the full on slalom boards too hard riding & too fast to control in sharp chop.
Maybe I'm too old & soft but the loss of about 1 or 2 Kn for me is worth it, it can turn a bad days sailing into a pleasurable cruisey day
I believe the *Board futura is very similar riding.

One quick & easy way to calm a board down is use a weed fin, it's surprising the difference it can make.
They are just as fast also, ask Jesper, he has some new ones that he is raving about

Yesterday I compared a vector Volt (upright slalom style) with an EX (similar but swept back about 5 deg)

The EX felt smoother & made the board ride flatter & less flighty just as Jesper advised.

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Paul Kelf said...

This is the exact reason i ride Exocet Cross boards, I find the full on slalom boards too hard riding & too fast to control in sharp chop.
Maybe I'm too old & soft but the loss of about 1 or 2 Kn for me is worth it, it can turn a bad days sailing into a pleasurable cruisey day
I believe the *Board futura is very similar riding.

+1 for the Exo Cross. Love mine. Flatters my sailing.

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Windxtasy said...

I have a 74 L waveboard. For sure it is much easier to sail in chop when it is windy but I want something faster...

Then I suggest a smallish custom polyester slalom board. If you can still find anyone who can build you one.

Something like this:

So small speed boards are just for really flat water then?

Lao shi has lent me his old 50W 70L ish custom speed board to try and I might get out the 50W 70L waveboard for comparison next time it is windy. I'm keen to have a good session with my 4.9 Koncept instead of it feeling like hard work!

Well nit really, although I can see why you ask because of the photo.
This board was my smallish speed/slalom board for many years from late '90's to about 2006 when I got the Isonic50 for speed work.
I went peak speed of 44 knots on that polyester board! It was originally an A box fin set up and I changed it to a Tuttle box so i could run the good speed fins in it.
But I still used it a lot for blasting on the lake and it worked really well for that. I have a slightly larger one that I used more but it was glassed too light and eventually I rolled the 'a' box fin box over. Still sitting in the shed waiting to be restored and fitted with a Tuttle box. I should get onto that..........

The advantage of a small polyester board with slalom type rocker is that it rides flatter than a wave board. This makes it faster over the chop and, with the inherent dampening, reasonably controllable. I can send you some outlines and rocker line measurements if you want to have one made.

Polyurethane/polyester/fibreglass used to be the way all custom boards were made before the obsession with super light weight and epoxy/styrene. In smaller boards it is still reasonable weight. It is also a lot easier to shape and glass and there are plenty of surfboard craftsmen around with great glassing skills. The only problem may be getting a polyester blank that is the right size and rocker. Not sure who is still making them....

Today tried the 85 Sonic, 50W 70L speed board and 50W 70L waveboard (in that order) in 20-30 knots at high tide in Safety Bay. Moderate chop. Same 4.9 Koncept and 26 weedie in all three boards.
The 85 Sonic and smaller speed board were comparable in speed although the small one accelerated faster, felt similar handling wise. The waveboard felt safer but was 1-2 knots slower.
Had fun on all 3 boards, not totally comfy but not scary either.
The wind and chop picked up a bit through the afternoon and energy levels went down, so perhaps the smaller boards were an improvement...