I'm not sure it's as relevant for race boards as it is for surf.

Take this example: A Race board is usually around 300 Litres give or take.

The actual hull of the board will theoretically float you at 95 liters with the paddler at 95kgs. If you make that board 14' long, 27 wide you really only need to have say a board 2 inches thick. This is totally disregarding any way the board will interact with the water, water coming up the nose, the board, the board leaning over and water coming onto the deck. This is just the hull on perfectly flat water paddled perfectly flat. The only thing affecting the speed of the board is the shape of the hull. To explain what I mean, imagine your board with everything sliced off above the waterline.

Of course this situation never happens. So we have what is called reserve buoyancy. This allows the board to deal with bump, chop, instability, waves etc etc. For flatwater in a lane race or the like you need less reserve buoyancy which means a lower weight, faster board.

To stick with the example above using that same designed hull for the board to deal with bumpy conditions or ocean etc you need more volume, particularly in the forward area. This keeps the board above the water and allows more stability given our falling forwards position.

I have read people asking that if they get a thicker board will it carry more weight, I don't believe so. As it is called reserve buoyancy the added volume really only makes you higher out of the water, the hull will still displace the same amount below the waterline despite its thickness.

For a larger guy you need to have a well designed board or compensate for failings in the design by adding stability and forgivess by going wide.

Sorry for the essay but this is my understanding. Happy to have alternate opinions disputing this. It's a great topic.


To summarise, basically the volume of your race board is really only relevant to its purpose and how it is distributed throughout the design and your own requirements for stability etc.

Really good explanation I thought CMC.

The theory behind displacing 90kgs in comparison to say 80kgs on the same shaped board is what I was wondering. Would extra foam in lets say thickness help the heavier paddle move easier across the water or create what CMC is calling negative bounancy or do you have to increase length or width to create a more buoyant board.

It had just got me thinking about what weight, height and size favours a SUP paddler at an elite level. At this stage SUP favours people between let's say 70kg to 85kg for professional athletes, rather then a sprint kayaker as an example at between 85kg to 95+ kg

That is a really good point about trim isn't it. I find that my 14ft Fanatic is quite sensitive to trim to. I notice that if I am just a little too far forward or a little too far back it changes the whole nature of the board. I have also noticed that if I am heading into wind and I don't sink the nose a fair bit its quite the work out to go fast (well fast for an old fat bloke anyway).

When watching my DW vids with my new high front camera mount I'm amazed at how much water flows over the rails and deck at times and it has me thinking if it was 1/2" thicker through the deck and tail it would be much faster.. I guess I am close to the upper weight limit for a paddler paddling this board so it's to be expected.. I can see future 12'6" and 14" boards getting thicker.. not thinner.. unless its a custom shape for a light weight paddler and being thinner is more about saving weight than reducing the deck height.... IMO..

DJ

I agree you can only go so thick.. When you look at an Ace you can see there is no possible way for water to ever flow over the rails or tail.. I'm sure that has something to do with why it's so fast.

DJ