Adding Another Sheave to the Masthead

[bradley1968]

Hi,

I am currently planning a mast overhaul project for next Spring. Among other planned enhancements, I want to move to a full batten main with lazy jacks and a lazy bag.

The only problem I have discovered (so far) is that my spar has only 1 aft facing sheave with a single halyard serving double duty as a topping lift when shackled to the end of the boom, and a main halyard when moved to the head of the sail.

In order to attach a lazy bag (and ease sail handling) I would like to somehow add another aft facing sheave to the mast head to have a separate main halyard and topping lift.

Any ideas how to best accomplish this short of buying a new spar?

Thanks,

Brad