Adding a foil to an outboard does provide a performance boost much of the time.
Adding a foil to an outboard does provide a performance boost much of the time. The smaller the boat the more significant the impact is, especially on boats that don’ t have trim tabs. On a 16 footer with a mid-sized outboard and no tabs, for example, a foil will usually level out the ride by forcing the stern up and the bow down, and will end or greatly reduce proposing. There is a performance boost, usually of two or three MPH at cruise, as a side-effect. In other cases, specifically with power cats, foils will reduce the side to side rocking motion that often accompanies a beam sea. The picture you see here is of my own boat, a 22 Glacier Bay. When I added the foils side to side motion dropped in the 10 to 15 percent range. What about a performance boost? No dice; in this case speed remained identical to foil-free operation.
Should you add foils purely to get a speed boost? Probably not. Although there are a lot of claim–mostly by the foil manufacturers–of speed boosts, if there isn’t another performance problem the foils solve (like the trim issues) then speed remains the same.
Of course, many people want to give a foil a try but hesitate, because it means drilling holes in the anti-ventilation plate. But check out Sport Marine’ s SE Clip, which allows you to mount Sport’ s foils without drilling. Meanwhile, if you’ re confident the foil is a must-have, traditional drill-and-bolts like those from Stingray work quite well. So back to the question – should you put one on your boat? Only if there’ s a problem like those mentioned above which you’ re trying to solve. If your boat already performs well, however, you shouldn’t expect these things to work magic.