Which foil pumps the best? What is the key to pumping a foil well?

Author: Jon Mann

Disclaimer – I won’t say which foil is the best foil for pumping. Why? Because there is no one best foil for pumping. Pump is a foil characteristic as well as a discipline, easy to confuse so for clarity, in this post I’m going to address pumpability (is that a word?) / the characteristic. 

Wherever I see this question come up, I feel it opens up a heap of other questions. The answers on forums have many people divided with opinions ranging on which foil pumps the best because yeh, everyone has an opinion, everyone has confirmation bias that the gear they have chosen is the best (after all its expensive), and I would probably urge people not to project their choices on others and remain open minded that there are other (equally as good for their own reasons) options out there. 

Anyways, I digress, back to the main topic. For me this question is probably an outcome based on a list of considerations which can lead you down a couple different avenues. So I’m going to try and list out the considerations as to what makes a good foil to pump and considerations to make when choosing a foil:

Let’s start with the basics. Lift. Lift is dependent on a number of things. Foil section (shape of your foil), area and speed (squared). Some foil sections are ‘liftier’ than others, some are also ‘draggier’ than others (depending on thickness and surface area). A bigger foil will give you more lift (lift scales linearly with area, double your area, double your lift), however larger foils also have more drag. Lastly, an often overlooked factor is speed. Going faster will give you more lift (square ratio, double your speed, quadruple your lift). Often you hear people commenting on how surprised they were that such a small foil had so much lift when they downsize. My opinion is that typically as you go smaller, you generally go to a foil that will naturally need to, and want to, go faster. Therefore giving you more speed (and therefore lift) to account for the lift you (think you) lose by going smaller. As you can see, compromises need to be made and the best choice (for you) is based on where you are and aren’t willing to compromise in order to have a foil for your intended use case. 

The key – intended speed range?

This is the most important consideration and the key to pumping a foil well (I’ll write a separate post on pumping technique). All foils have an ‘optimal speed range’ (not a technical term, but let’s roll with it) in which they pump. Below that speed range (yellow) you can pump them up to speed, but the effort / reward ratio is lower and below your stall speed your foil just drops out. In that optimal speed range (green) you are getting the best return on your exertion, and above that speed limit you actually aren’t gaining much or anything.

What discipline are you doing? This influences the speed range that you need to look at. A foil that pumps well prone foiling (higher speed) might not be great for dockstarting. In fact there are plenty of small foils that guys have no problems connecting multiple waves with thanks to the speed which you can carry out of a wave that most people cannot dockstart. Conversely there are plenty of amazing dockstart foils that no one wants to surf foil as they are too slow and draggy (consequence of a foil section that may be thicker with great low end lift).  

I’ll try to visualise my thoughts to try help you read less (though there’s more below)