Thought I would put a few of these up for your viewing pleasure.The rigging knife differs from a rope knife in that it has;in addition to a sheep foot master blade a folding marlin spike. The sheep foot blade has a straight edge that is laid against a piece of rope on a flat surface and struck on the spine of the blade usually with either a piece of wood or iron to sever the rope. The marlin spike or fid is used to separate the individual strands of rope to allow it to be spliced.Most will also have a blade to open metal food cans.There will also sometimes be a shackle key built into the handle or occasionally as a separate blade.Yachtsman's knives will always have a shackle key as it is used on sailing vessels.
Although the term marlin spike and fid sometimes are used interchangeably there is a difference. A marlin spike is usually made of steel and can be used on either rope or steel line whereas a fid is usually much larger;made of wood and used primarily on large line(rope) .At least that is what I was taught.
They were mostly issued to sailors although one of the knives I am posting(the I*XL knife)I believe was a British Army issue knife.
The first page includes mostly military issue knives from Italy;England and Australia.