Sean M wrote:
it looks like he makes his out of twisted bar stock and fits two hooks on them.
Double hooks are what happens when we turn our modern minds to the question of crossbow spanning. We just can't seem to accept the idea that one hook will bring the string to center, so we "improve" it. The idea seems to have begun with Viollet-le-Duc, and has grown to be a standard of modern illustration since then.
To the best of my knowledge there is only one example
in art of a guy using a double hook. It sort of looks like the artist couldn't decide which side of the bow to put the hook on, so he did both.
Now... there are double hooks; but they are the sort that have a built in pulley or roller. This one is typical.
Sean M wrote: He uses steel nuts, which Iolo does not like.
Steel nuts are not an authentic solution, but it's easy to see why people use them. It's difficult to get good antler for nuts, and tedious to set in a steel insert for the trigger to bear against. Theoretically, steel nuts rob the bow of power by being heavy and slow to accelerate, but I don't know how much difference it makes.
Sean M wrote: Is spanning with a single hook more fiddly than spanning with a pair? In the art it looks like the single hook slides longside the stock until the nut catches the string.
It's not as difficult as you might think. After a bit, you just learn where to put the hook so that it ends up bringing the string up centered. The double hook is an invention to solve a nonexistent problem.
The difficult thing about spanning with any hook is learning to balance yourself while you do it. I recommend practicing with a light weight bow until the motion it smooth and natural before moving up to something heavier. I learned on a 75# "baby bow", and found that the step up to 150# was pretty easy. I once taught someone with no earlier experience to span their 175# bow with a hook. It was a bit scary till he got the hang of it.
Sean M wrote:It looks like if you wanted a replica of a late 14th century crossbow, a belt hook would be a safe choice, but there were probably spanning devices which allowed a stronger draw like the doubler belt or the windlass or the screw jack (and what were the mounted crossbowmen using- hand span braced against their body?)
For the late 14th C, a belt hook typical an normal.
I have no idea how mounted crossbowmen spanned their weapons before the advent of craniquins or goat's foot leavers.