Salimaker's Hook also called Sailhook, Benchhook, Stretching Hook or Third hand. Used to hold canvas, while pulling tight with the left hand. This ensures the canvas is tight while stitching, keeping the seam straight. See illustration below.
Subject: Bench hooks, oh my!
My bench hook odyssey -
I work at San Francisco Maritime National Historical Park. Not one of our shipwrights knows where I can get bench hooks. One gave me a method of manufacture using heavy wire and an anvil.
That's okay, I'll just go to CoMar - that's Coast Marine one of the oldest industrial ship chandlers around and also just next to our National Park. George works the counter and can get you ANYTHING. Need a pump diaphragm for a 1950's model now-out-of-business company bilge pump? CoMar has it on their shelf or George can order it and have it in probably the next day. Bench hooks? George has no idea. He does say however that if he could find them, he sure could sell them.
The search went on until I found your site! Thank you,
San Francisco Maritime