How much faster is a 14'26'' or 25'' then a 14'28''?

[ROH]

Maybe a bit difficult to answer: But how much faster is a 14' with width 26'' compared with 28'' (both flatwater boards with more or less the same shape)?
With a 14' 28'' I'm going around 6 or 7 km/h how much can that be on a 26''? 7 or 8 km/h?
Or is there not so much difference between 28'' and 26''?

[pouch]

I would say that you would be 0.2 to 0.5 km/h faster within similar conditions

[coolas]

They have exactly the same speed limit, which is just proportional to their length.

A 14' will be (14 / 12.5) times faster than a 12'6" for instance (12% more).

However, width (and the quality of the hull shape) will add more drag. So you will spend more energy to reach this speed limit and maintain it.

So, if you do not have the power and technique to maintain the speed close to the speed limit during the whole session, a wider board will be slower. By how much depends only on your technique and stamina.

Or, in other words, if you end up not totally exhausted from your session, you have enough energy to spare to afford the comfort of a wider board, but if your board rolls underfoot (cerating drag), or you fall from time to time, you will be faster overall with a wider, stabler board.

If you are a racer, you can go a bit over the speed limit with a considerable amount of energy, so the tiny bits of extra speed can mean some meters after some kilometers, and may be what will make you win the race, so you want the narrowest board you can paddle steadily, as in a race, every gain counts, even tiny ones. But if your board is moving to catch your balance, the added drag will anihilate any speed benefit.