Take a short length of thin dyneema and loop it around that pin and your hand several times, making a loop maybe 3 inches across. Tie the two ends together securely, using knots what will not slip.Due to the weight of the mast aft of the crutch and the need to "wiggle" the mast to get the pin through I find it too awkward to also try to install any kind of vang hinge while attaching the mast.
I have been searching for a good solution (if there is any) to attach the vang to that pin after the mast is pinned and up.
Does anyone have a solution they like?