Ok, bear with me--don't know all the parts names. The piece on the forward (mast) end of the boom that slides into the mast and is attached by a post that goes inside the boom end and then connects with a cotter pin to another piece INSIDE the boom has come out and the other piece(s) remain inside the boom. Looks like the pin got bent. It appears the ONLY way to reattach it properly is to remove the end cap. However, the attachments holding the end cap on to the boom appear to be round grommet type things installed in the factory...how does one make this repair or remove the end cap on the boom? Thanks!!

Drill out the round grommet type things, taking care not to make the holes in the boom and the end cap bigger. You should then be able to remove the end cap and make the repair. After that you will need to reattach the end cap. I would use aluminum pop rivets. I would also put a light covering of silicone in between the cap and the boom as well as in the rivet holes before installing the rivets. It is important to use rivets made of the same material as the boom and cap which I assume are both stock and should be aluminum. There is not much linear force on that part so aluminum rivets should be OK

Thank you!!! I thought the rivets had to be drilled out but didn't want to try it without some expert advice. Everything is aluminum as you say and should be the same after the repair. Once again---this is a great site with really helpful fellow sailors!

Replace the rivets with either SS or monel as the factory did when it was new. DO NOT USE ALUM RIVETS, that section of the boom is under a lot of pressure and strain. Check any boom on any boat and they all have SS rivets, there is a reason, if the factory could get away with alum rivets they would have used them from the start.

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Check any boom on any boat and they all have SS rivets

Not true. Aluminum is used regularly to attach the boom end cap to boom, and the loads are compression on the cap into the boom (no loads on the rivots).

On the other hand, the gooseneck bracket that attaches to the mast should be attached with SS rivots.

Sailconi, when you remove the cap of the boom to fix the gooseneck swivel bracket you will find that the two pieces are attached using a SS bolt and nut. The bolt goes through the swivel bracket into the end cap and is secured with a nylon/SS locknut. Do not over tighten the nut and bolt as you want the bracket to just rotate. If you don't have a nylon locknut use two nuts to lock each other into place.

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Philip
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