Most of the ones which I've seen have been affixed with screws, or a line of small diameter bolts. Mostly running vertically on the trailing edge.
As to getting a perfect fit, a couple of options come to mind:
- Some neoprene, cut to fit, & glued into place.
- Tape off the bow with some clear plastic packing tape, & or Visquine.
Lay a couple of layers of cloth over this, & then some high strength bog. Like a mix of epoxy
& milled fibers.
Have a good coat of epoxy
already applied to & sanded into the guard, & then bolt in into place. Removing the excess bog as it gels.
Remove the guard, trim off the excess glass, peel the packing tape off of the bow, & reinstall it with sealant
on the fasteners, for a perfect fit.
Epoxy mixed with milled, & or chopped fiber (as in fiberglass
fibers) is used to bed
keels, & other very highly loaded items (the longer the fibers, & the more of them in the mix, the stronger it is). So it'd provide a seriously solid backer to such a plate I'd imagine.
You could also take a casting of your bow, & make a heavy duty mockup of the bow from it. And then us it as a mandrel onto which to hammer to a perfect fit, some medium weight stainless steel plating. And attach it as denoted above.
I've also seen a few done with/in. Multiple strips of stout wood
(a more work
boat'ish look), or some in UHMW Polyethylene. The latter is pretty darn durable stuff, assuming that you can get a good thickness, which will conform to your bow. That, or do it in vertical strips, akin to the wood
above, or even in a "Clinker Built" style. - NOTE: With this stuff, don't use a heat gun, you'll destroy a lot of it's physical properties.
Kydex might be an option too, however, I'm uncertain as to it's long term UV resistance. But it to is pretty dang durable, given that they make Military knife sheaths out of it. - NOTE: With Kydex, use caution if/when using a heat gun, as if you get it north of about 190 degrees Fahrenheit, it starts to give off acidic gasses (Hydrochloric if memory serves). Not huge volumes of the stuff, but... Read the MSDS on it!