Hunter 33.5 compression post replacement without de-masting — feasible?

[g.marion67]

I discovered significant rot in the wooden compression post on my 1990 Hunter 33.5, likely caused by a long-term skylight leak near the mast step. The upper fiberglass structure and lower pedestal appear intact, and there is currently no obvious deck depression.
The post is approximately 3¾" × 4", and at the worst area I measured roughly 2" of internal rot, with sound wood remaining behind it.
I’ve been researching repair options and found another Hunter 33.5 owner who replaced the post with a permanent adjustable steel jack post after removing the original wood post. He did this with:

• a steel load-spreading plate at the top,
• adjustable steel post,
• steel base plate at the bottom.

My question is specifically about doing the replacement without de-masting.
My proposed method:

1. Install a temporary structural jack post about 1 inch beside the existing compression post
2. Bottom support would sit on solid structural flooring/pedestal (not the shower liner)
3. Top support would bear on a load-spreading plate directly against the structural roof beam / casing, not the decorative fiberglass liner
4. Gradually preload the jack to transfer part (or most) of the mast compression load
5. Remove the rotten compression post and install the permanent steel replacement

Has anyone successfully replaced a compression post on a deck-stepped mast without de-masting?
Main concerns:

• Is a properly shored adjacent jack enough to safely carry mast compression during removal?
• Any issues with dynamic rig loads / stay tension while docked?
• Would you still recommend slightly easing the rig, or is that unnecessary?

I’m especially interested in feedback from anyone with Hunter 33.5 / Hunter 33 / similar deck-stepped mast boats, or anyone with structural repair experience.
Thanks.

 

[colemj]

I have removed a compression post from our previous boat (40' catamaran) without removing the mast. If you loosen the rig, the only compression that needs to be overcome is just the weight of the mast, and this isn't much. I used a scissor jack and a 2x4. I could get the 2x4 directly under the mast step. I can't tell if you can do this, but you do want the support under the mast and not just on adjacent deck. Also, our post was chocked in place top and bottom. After removing the chocks, I only had to raise the mast/deck a small amount to remove the post. I can't tell if you need to raise it a lot or not.

Mark

 

[jssailem]

The safe process is to remove the mast. This also allows you to inspect the mast and address any age-related repairs/replacements that are needed or have been ignored.

Most definely you will need to slack the stays and shrouds. You may need to replace the standing rigging. It is 35 plus years old, unless the it was refitted 10 years ago.

The northern climate is better than the caribbean climate, which looks at replacement at a 15 year interval.

A job well done will reward the owner for many more years than a job done on a shoestring and a prayer.

 

[BigEasy]

Did this repair on my 1988 Hunter 33.5 approximately 23 years ago. we removed the mast & advise you do the same to enable you to reseal the mast wiring that penetrates under the mast step and through the deck above the compression post. Leaks at that location caused rotting of my post. We fabricated an aluminum post from rectangular aluminum stock & welded cleats on the post to facilitate reattachment of the teak covering to conceal the post. I don’t see the need to make your new post adjustable; after jacking up the deck to allow placement of the new post, simply place aluminum shims under the post if necessary. Might be a good time to find an alternative route for the mast wires that allows resealing, in the future, without removing the mast.

 

[Don S/V ILLusion]

What is a “permanent” adjustable jack post? Adjustable posts are designed and intended as temporary. calling it permanent doesn’t change that. For that and all the other reasons others have stated, stepping the mast is the proper thing to do why try to avoid that?

 

[g.marion67]

Thanks for the info everyone. I think I’ll be going along these lines, installing a jack post permanently. Sry for not being clearer.

 

[g.marion67]

Thanks for the info everyone. I think I’ll be going along these lines, installing a jack post permanently. Sry for not being clearer.

My concern now with this sister ship retrofit is lightning strike protection!!