I think that's a bad crane design... it should not be centered, as mentioned already, and it's too long and drops too far...
Modifying that would probably make all your issues go away.. and enable you to go back to an internal halyard run.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)