So yesterday I cut out cockpit locker pans and hatches which leaves a nice sharp edge. If it is wood or fiberglass, that cut edge is sharp and needs to be broken so that it feels soft and is also strengthened. A sharp edge will break easily if hit by something and does not feel good when your arm comes into contact with it.
On fiberglass I just use a piece of 60 or 80 grit sandpaper and run it over the edge at a 45degree creating a small chamfer. This only takes a few strokes and I run my hand over it to feel that it is soft.
Wood usually needs something a bit nicer and so roundover bits were created. I’ll use a 1/8, 3/16, or 1/4″ roundover bit in a trim router to round the edges on the teak parts. You can just use sandpaper but that is a different look and not as strong as a roundover.
If you are wondering, a trim router is a smaller, hand held router used for small things like roundovers and flush trimming. Less power than a full size router and only uses 1/4″ shank bits.
Edge treatments are for edges that are exposed and you may come into contact with. If I make a part out of teak and the edge is making contact with the boat when mounted, I will leave that edge sharp. This creates a nice intersection between the wood part and the fiberglass and you cannot touch that sharp edge. More on this later when I make some parts.