Gilles:
I have one sample and am costing out what it would be to have them made by a chap that does alot of maritime ropework.
They are available in the UK at about 30-40 quid (60 to 80 bucks) which isn't bad until you figure in shipping as they each weigh in at about 25 pounds!
I need one more for the 25 pounder, two for the 17 pounder and two for the 6 pounder (they were, as best I can deternine, the same for all guns.) I'll probably get two for the 40 mm Bofors as well, although I can't remember if they are on the tool kit list.
The hardest part will be the hooks as they are a special item, long and slim with a slot for the leather keeper.
I'll let you know what I learn on the cost side of things.
Mike
