Replacing half moon blocks at base of mast

[Manipogo]

Ahoy,

I am hoping another Catalina 38x owner might be able to help. I own a Catalina Morgan 381, but they are very similar to the 380.

I need to replace the half moon blocks at the base of the mast and the boat yard tells me that they can't see how to remove the blocks without pulling the mast to get at the mast step. I've reached out to Warren Pandy at Catalina (who has been a life saver in the past), but I have not heard back from him yet. Has anyone else replaced these blocks, and if so, how did you remove them?

I really just need to replace the worn sheaves, but Garhauer tells me that they don't have replacement sheaves and the current half moon blocks won't fit the existing mounting holes. However, they have told me they will replace the sheaves if I can get them off the boat to send to them.

Any help or suggestions welcome.

 

[JoeWhite]

Images would help.
C36 owner.

 

[Manipogo]

Images would help.

Here is what I have on hand. The boat is currently on the hard ~6 hours away so I can't easily get more.

 

[JoeWhite]

Very good photos. I had not seen one like them before. It appears that you can remove a good one and take it to a boat parts store and buy a block that has a similar sheeve and pull out the sheeve and install on your vessel. Have you attempted that solution ? Removing the sheeve only would require removing the nut from one side and pulling out the bolt from the center of the sheeve. It appears that someone has already removed a sheeve and installed a plastic sheeve that does not fit well. I do not think the mast or the mast step needs to be removed.

 

[Ward H]

The mast base the blocks are on looks pretty beefy. I expect the blocks are just attached by machine screws into threaded holes in the base.
It looks like just the sheave and sheave carrier can be easily removed. As Joe said, try pulling the bolts out that go thru the sheave. The sheaves may just lift up. The pin at the mast end of the block looks like if it is removed, the block side plates could be wiggled off the block base.

 

[jssailem]

This image of the ones photographed looks identical to the current block made by Garhauer.


This one appears to screwed or bolted into the deck plate. I would try first to remove the through bolt of the sleave. One side looks like a lock nut and the other a plain bolt head. The sheave should slip out vertically from the sides of the block.

The white plastic sheave looks to be a wrong part fitted into the Garhauer frame.

Removing some of the blocks may be done (best SWAG) by removing the sheave, then rotating the housing 90º and sliding the housing off the block base. This may give you access to the screw heads. The ones that look flat I suspect are bolts. These are likely available once you have access to the bottom of the deck plate. That access is going to require the removal of the mast. Not a desirable process unless you have other work planned. I suspect that is why the new model by Garhauer used Phillips head countersunk screws.

Good luck.

 

[Manipogo]

Apologies for not following up sooner.

The mast base the blocks are on looks pretty beefy. I expect the blocks are just attached by machine screws into threaded holes in the base.

Yes, but some of them are screwed in from the bottom... These keystone blocks get in the way of removing the block next to them.

It looks like just the sheave and sheave carrier can be easily removed.

If it was easy I wouldn't be here. The sheaves themselves are easy to remove, finding suitable replacement sheaves not so much. Removing the housing is next to impossible as the block needs to be laid flat to slide the housing off. So I need room on both sides, one side to lay the block flat and room on the other to slide the housing off. Which means to remove one I first need to remove the one beside it, and eventually we get to the one at the end of the line that is screwed in from the bottom of the plate and is impossible to remove. Neither Warren P at Catalina, nor his contact at US-Spars can figure out how it got that way...

This image of the ones photographed looks identical to the current block made by Garhauer.

Yes, they do look identical, but sadly looks are deceiving. The sheaves for the current block made by Garhauer will not fit (according to Garhauer) my old blocks. Even if I was able to get the old blocks off, the new blocks don't match the existing mounting holes (because why would they... sigh).

However, a major (major) shout out to Mark Felgenhauer at Garhauer who rummaged around in their old parts bin to essentially make me a custom set of sheaves to fit my old half moon blocks. The boat yard has the new sheaves, and I haven't heard any bad news from them, so I hope they went on without too many problems. Fingers crossed.