For the racing we do on the Chesapeake I've taken them off my 18. They were about 40-50lbs of weight (boat's already damn heavy and so am I), extra windage going upwind, and it really doesn't take much to stick the leeward one in the water with a bit of heel and chop. And counter-intuitively, slowing like that in blow makes things worse, not better! Trapping from the hull gives better leverage than hiking (not trapping) on the wing, and although trapping from the wing is cool and is way more leverage we rarely see conditions that make it useful. That having been said they're the best thing for cruising, and even though I've taken them off I still keep them for that purpose. Now that I have a spin I think about putting them back on, but as of yet I haven't seen a need.