I'm using the Spinlock Line Cutter Knife hopefully for many years, without rusting.
They say "it is a must for anyone employing tethers or safety lines.
It’s a very high quality safety tool enabling a sailor to cut free with a “valley”
like shape to keep the blade unexposed,
yet ready to use, preventing accidental cutting of both you and your gear.
A good, compact handle is designed to be easily grabbed onto when needed and comes
with a lanyard secured to it's sheath. It is lightweight, compact, and intuitive to use.
A great gift for any offshore sailor."
I paid $34.99 at Westmarine because I wanted it so bad,
but than I saw it HERE!