Hi Max,
Perhaps I didn't explain it very well initially, but the halyard goes back inside the mast at an exit plate located about 6 feet below the masthead, and not over one of the masthead sheaves...
I suspect the load from flying my Code O near the upper limit of its recommended range are likely the heaviest the crane will ever see... I doubt I'll ever attempt to hoist anything more substantial than my inflatable with a 2 HP engine and all its gear, probably 200 lbs, max...
All I know is, it's handled the loads so far on this boat, for the first 40 years... (grin)
best regards,
Jon