Hey guys. I am about to get a 14 foot prone board.  I have a feeling it will probably come with a small futures keel fin, which I would assume would be great in flat water. What would be a good after market fin for open water or downwind? Do I use a fin similar to what I would use on a stand up? Futures downwind fin? Any suggestions?

As a general rule the fins on prone boards are less robust than SUP. This should make sense as you are not going that fast and you done need as much surface area to oppose the forces of your arms vs. a sup paddle to keep you going in a straight line and propel you forward by opposing the force of your stroke. As you already know, most people usually just use what comes with the board. You (and many other experienced paddlers are) not everyone. Moreover, the fins that come with some boards may be too small for some paddlers.

One place to start your research is our article about prone fins. In that article we discuss why you might need a larger fin and take a look at the NCP fins http://www.ridingbumps.com/2014/03/29/larger-fins-for-prone-paddle-boards/

Since you are asking specifically for a downwind/open water fin, you should check out the new Futures RFD fin. It is a downwind fin that Jack Back and Zeb Walsh designed and used at this years Molokai race. I looked on the Futures site today and it is not listed yet. Maybe contact them and see when it will be available. It is mentioned in this article.

If all of that does not work, you can just get a 9 or 10 inch fin that you would use on a regular surfing long board. That is pretty much what the Commander Stock Prone Board from Surftech comes with. There are loads of options there. Here is our guide to the general shapes of fins.

Price: $34.95 Prone Paddleboarding: Essential Techniques from breedfreakphoto on Vimeo .