Upgrading boom fittings
When sailing with reef nr 1, we constantly heard a squeaking noise. Squeaking is not good…..it means something is chafing and wearing out. I tried WD40 but that did not solve it. Being able to reef effortless in all circumstances is very important, so I decided to look at all fittings in detail. This what I found and how I solved it:
The horizontal pin, that attaches the boom to the gooseneck fitting, eats its way into the aluminium boom. The pin is a bushing with a large bolt through the center. My Pin was slightly bent, which caused problems with the sheaves getting stuck.
A workshop made two flanged bushings for me and a new solid pin of the same size as the original. All I needed to do was to increase the holes in the boom to 34 mm to accept the larger flanged bushings. I used a stepped drill for that. The larger flanged bushings have more surface area so they should not eat into the aluminium. The flanged bushings will not rotate like the original pin, which will eliminate wear too.
Forward end boom sheaves
I noticed that one of the sheaves (reef number 1) was cracked. The white plastic sheaves dry out in the UV and lose their strength. I had bronze sheaves made to replace them. A bit heavy but they will last a lifetime. Bonze is self-lubricating.
Aft end Boom sheaves
I also took the end boom sheave assembly apart, which is quite easy to do actually. There are four sheaves that are held in place by a pin, which runs through an aluminium extrusion that has 4 slots for the sheaves. The pin is knurled (rough) on one end to keep it place. My pin had moved out, such that it was no longer being supported by the aluminium extrusion on the other end. The load on the sheave then bent the pin, preventing the sheave to rotate.
I replaced all sheaves by Bronze sheaves and had a longer pin made. This pin has the same length as the internal width of the boom. No need for a knurled end anymore. The longer pin can never move
Niiiiiice boom upgrade !!
Thank you Richard!
Can you provide drawing for boom Bronze sheaves and /or supplier Maschine shop in Holland?
Would appreciate your help.
Hi Brad and Teasy here. Any chance you have a part number for these bronze sheaves? A few of ours are destroyed. If you have any details on the upgraded pin size you made that would be awesome as well. Hope all is well!