Posted by JimM on September 03, 2002 at 08:01:48:
In Reply to: Re: Air foils ? posted by Frank H. on August 29, 2002 at 21:18:57:
Makes me think of a spoiler that came with some mods of the Dodge Challenger in the early '70's. The purpose of a spoiler in a race car is to provide an aerodynamic negative "lift" to push the rear end down and increase traction. It's only effective at extremely high speeds, probably over 100MPH. Many people thought it made cars look "racier" and added them because they thought it looked "cool". Some even had the impression it improved performance, which of course is total nonsense unless they're in sanctioned racing.
I've seen some high-performance pleasure boats with spoilers, only for looks. The idea of trying to push the stern (or any part of the boat) down is totally ludicrous. Even trying to pull it up could only make the boat less stable, but it's a moot point since the speeds aren't going to be high enough to derive any lift at all.
From this, you may gather that I am "anti-spoiler", which I must confess is true. I like sleek lines and I like classic lines, even old-fashioned lines. But spoilers just don't belong! They don't DO anything!!
But if you're serious about adding such a "styling feature", here are some thoughts: First and foremost, it must be strong enough to carry it's own weight and dynamic loading caused by pounding through seas and wakes, and maybe docking impacts with the pier. Second, it ought to look professional, no band-aids or bubble-gum, and have a good finish. It probably ought to have clean lines, as in a continuous curve from gunwale to gunwale. Although, I suppose you could have two vertical stanchions with the 'foil mounted perhaps a couple of inches down from the tops. That, if you like the idea, would be much easier to fabricate.
If the latter approach, I would probably run the stanchions through the gunwales just inside the sheer. I'd probably build them as "boxes", maybe 6" wide (fore&aft) and 2-3" thick, and worked into a nice tear-drop cross-section. That's the only way I envision them being sturdy enough - otherwise, the rig would tend to flex a lot underway and would feel flimsy. The foil could be built similarly, but in a thinner section. Everything would be well-encapsulated in 'glass-epoxy.
This sounds like a major job for something that's purely cosmetic! And, no, I never noticed any pre-fabrcated spoilers on the market, but you could try a websearch. Good luck!