I have a question about the sheave for main halyard sheave at the masthead. How do I get fix this one? My Masthead mainsheet sheave appears to be frozen.

I have seen the drawing in the Ariel Maintenance Manual on page 21, and I am aware of the parts list on page 129, which appears to represent that the masthead sheave for the main halyard is part number 21076 with dimensions ½ X 6 ½ X ½, however, I am not aware of a material specification for or source for a replacement for this sheave from reading the manual or the posts on this forum. I have not been able to locate in the West Marine catalog a sheave anywhere near that dimension.

The Ariel Maintenance manual recommends enlarging the diameter of the hole through the center of the sheave, and pressing in a bronze sleeve bearing. I assume that the dimensions ½ X 6 ½ X ½ on page 129 of the manual mean that the sheave width is ½ inch, that the diameter of the sheave is 6 ½ inches, and that the diameter of the bore hole through the middle of the sheave as built is ½ inch.

I have been engaged in the effort of restoring my Ariel hull #330since September 2001. I had a surveyor do a cursory review of the hull, deck, and rigging before I adopted the boat from the Sea Scouts, and I engaged a rigger in October 2001 to modify my backstay for a tabernacle, and look over the rig with the understanding that I would further engage him to repair or replace anything he found to be in need of repair or replacement.

The bill that he submitted to me last spring reflected only his work on the backstay and backstay chain plate. I do not believe that he ever went aloft. The surveyor performed his inspection with binoculars from the dock. Therefore until today no one took a close look at the masthead. Today I did, and everything up there looks spiffy with the exception of the sheave for my main halyard. I intend to replace both my main and jib halyards with rope, but now they are wire to rope, with the connection being a bowline tied in the rope portion and threaded through a swaged eye.

As might be suspected, the swaged eye does not go through the sheaves for either the jib or the main halyards. In both cases, wire is the only material that currently runs through the sheaves. Since I now have an operational tabernacle rig, today I lowered the mast as close to the dock as far as I could lower it (eleven feet from the dock to the masthead bolt that serves to secure the two upper shrouds and also serves as the axel for the main halyard masthead sheave). The jib sheave appears to be in good condition, and it works smoothly, but the main sheave does not appear to move when the halyard wire is pulled through it. In other words, the sheave appears to be stuck, frozen, jammed or however it is proper to describe something that does not move, but is supposed to do so.

I am drawing these conclusions by standing on the trunk cabin on another boat, and looking up about six feet. I will shortly pursue options that afford me a closer look, but it appears that the main halyard sheave is scarred by the wire halyard. The sheave itself, when viewed through the slot in the front of the mast, appears to be rusty.

The main sail is extremely difficult to raise, but I have done so on sixteen occasions, since I began sailing the boat on Labor Day last month. Yesterday, I reefed the main in about 20 knots of wind while single-handing, and it was possible, but again not exactly a piece of cake. My guess is that I am, by brute force, dragging the wire halyard through a frozen sheave. I have no halyard winch for the main, although there is a jib halyard winch on the port side of the mast, so I am pulling the main up by hand, but it feel like it takes a lot of force to get the main up all the way. Actually raising the main is fairly easy until the last five feet or so, provided that the mainsheet, downhaul and boom vang are slack. Then it gets tough.

I don't want to drop the mast to inspect, repair or change out the sheave. Due to lifting limitations I would have to pay a yard to have unstep and restep the mast with a lift, but I might be able to use my tabernacle to lower the mast to a raised dock where I could repair or replace the sheave.

Has anyone else had to deal with a malfunctioning masthead main halyard sheave, and how did you deal with it? Changing a sheave does not seem like it would be too difficult undermost circumstances, but I do not have specifications for this sheave, and the axel on this sheave is also the support bolt for the upper shrouds, so removing the axel would leave me with no lateral support for my lowered mast during the repair or replacement. Any advice will be appreciated