What Is A Sailmaker's Palm?

This is a device used by yachtsmen, dinghy sailors etc to make repairs on sails, and sometimes to whipp or bind the ends of ropes or sheets as they are more properly known to the initiated.
The small device consists of a loop of leather with a hole for the thumb to go through. The widest part of the leather sits across the palm of the hand and incorporates a dimpled metal plate to accommodate the blunt end of a needle.
Sailmaker's needles are necessarily tough and big enough to take the heavy thread - these days synthetic to resist the destructive effects of weather and sea - and the plate, held in place across the palm, is used to force the needle and thread through the tough material of the sail.
There are two types: a seaming palm and a roping palm. The main difference is that the roping palm is heavier and has deeper recessed dimples and a tougher leather backing.