Hello,
You can see an article about the Hook Lever here:
http://www.northernadvocate.co.nz/ne...pular/1107154/.
Whether it is an improvement over the old ABI monstrosity depends on how much tension one can apply with it. With the ABI, if you adjusted the turnbuckle so that you could, with great effort, close the hook, the leverage was still insufficient to tension the forestay on most cruising boats, sufficiently to have any hope of a flat luff in a storm, and there was no way to tension the stay further after the hook was closed. And while it is possible to use (some) runners to tension the forestay, they can easily invert the shape of the mast, thus making for bad shape in the main.
If the Hook Lever has better geometry, then maybe closing its hook could give you sufficient tension. Anyone have info on this?
Fair leads,
Brion Toss