Frozen Out

Roy Labonte of San Bernardino, California, asks:

"The main and jib halyard sheaves on my Islander Freeport 36 are corroded and frozen at the masthead. I freed the pins on the sheaves by knocking them back and forth with a rubber mallet. But I have had no luck freeing the sheaves themselves. Is there any way to get them away from the mast?"

Don Casey replies:

Maybe not, but if you are patient and have time, a penetrating lubricant such as PB Blaster (pbblaster.com) can work wonders. The trick is to keep the edges of the corroded area wet with lubricant. If the mast is in the boat, this means making a weekly ascent to the masthead. If you can drive the pins all the way out, replace them with a piece of line that goes through the center of the sheave. Once the line is secured, smack the edge of a sheave with a rubber mallet. If possible, also try inserting a putty knife between the sheave block and whatever it is stuck to. If you can’t remove the sheave pins, putting a small, low-stretch line around the sheave at least once will also let you apply considerable torque to the sheave.