Masking tape works great. Combined with a few spring clamps here and there and a few stapled/screwed down scraps, you can do the whole boat (well, maybe a few staples on the tough bends on the hull).

With cove and bead strips, I put a short piece of 1/4" dowel in the cove edge before running the masking tape over it to protect the edge. Sometimes you need to peel the tape carefully so it doesn't pull out a splinter of wood at the edge - not a big problem. Use new tape each time as Jason said, and pull it tight. It has a fair bit of stretch and takes a lot to tear unless you stretch it over a sharp corner. Use long pieces of tape and rub them down real good so they don't slip. I usually tear off a bunch of pieces of tape and "store" them on the forms so they are ready when I am installing a strip. Goes real fast.

Grant