The 60 minute compression post

[hummingbirdbassist]

Disclaimer: where there may be professional builders, mechanics, technicians and naysayers alike you should only do what I am about to describe as having been done for me at your own risk!
I picked up a Cherubini 30 footer that needed some work, most dire was the compression post. After reading many sites and DIY's I realized I that I had 2 choices pay out the wazzooo( I got some wazzooo estimates) or DIY!
Being DIY challenged but never afraid to try I went for it! After researching and talking with several mechanics, technicians, and experts and wanting to sail I met a gentleman who put me totally at ease! He told me a "few simple measurements and we can have it done in 60 minutes!
Without taking down the mast, he said of course!
The day started with him coming by and getting a measurement for what was to be a compression base made of solid aluminum! A couple days later he sent me pics of my new compression base.( will post pics at end).
The day came to put base in, he said he can do it in an hr! For giggles I started my timer.
1st he loosened all shrouds
Then went below deck
Using a block of wood ,a 2x4 and a 1x6, a bottle jack and a small car floor jack he went to work!
Jacked up the ceiling and then used car jack to straighten out bent I beam in bilge. Instead of cutting out I beam he shaved out access fiberglass used on Ibeam and a few hammer taps later my new post compression base was in place, some 5200 to hold it in place and the rest is history and he literally had it completed in about 55 minutes!

 

[rardiH36]

Fantastic! I have always wondered if loosen-the-shrouds-jack-up-the-ceiling then just replacing/wedging something appropriate down below would be plenty good enough. Your description gives me encouragement for the day I decide to take preventive action before anything actually starts to sag.

Any guess how far the ceiling moved up with the car jack? 1/4", 1/2" 1"+ inch?

 

[hummingbirdbassist]

Rardi,
My post was in a crazy way, one post said the cheese had slid off the cracker , meaning my post was leaning off to the port side, but given your question, I would say it went up little over an inch for clearance

 

[hummingbirdbassist]

 

[hummingbirdbassist]

 

[H30Gary]

Great job Hummingbird. Wish I had seen your post before I pulled my I-beam out. Your approach is much easier!

 

[kito]

My I beam was rust out too. The bottom flange was encapsulated in epoxy and was in good shape. Just the Ibeam web was bad. My mast is down so mine was easier. I just knocked out the bad piece and ground the remaining steel web down to about 1/2". I chipped out all the epoxy so my new base would sit on the bottom steel flange. I made my base from 2 pieces of 6" structural aluminum channel, bolted together like an I beam. I also placed a piece of epoxy coated oak sandwiched between them so there is a gap to slide my new base over the remaining steel ibeam web. I will built a dam around the bottom flange and fill with resin to hold it in place and keep protected from moisture.

 

[centerline]

Fantastic! I have always wondered if loosen-the-shrouds-jack-up-the-ceiling then just replacing/wedging something appropriate down below would be plenty good enough. Your description gives me encouragement for the day I decide to take preventive action before anything actually starts to sag.

Any guess how far the ceiling moved up with the car jack? 1/4", 1/2" 1"+ inch?

there is actually quite a lot of "stretch" available when jacking the coach roof to work on the compression post or bulkheads, providing all the upper attachments are loose so you dont try to lift everything loose from the floor, or otherwise pull the attaching hardware out that should have been unscrewed...

it creaks and groans a bit as you lift it, but thats normal for any fiberglass that has been sitting in one spot for several years....

 

[H30Gary]

Here is what I am doing. No doubt more expensive than what others have done, but hopefully bullet proof. First, I removed the I-beam (technically an H-beam, because the flanges are not tapered). I'm having this beam duplicated, in 3/16" SST. This cost about $300 - probably would have been cheaper had I not gone to a "marine" metal fabricator. Second, I'm installing a second compression post, sistered up against the original post. This new post will carry the load from the mast to the H-beam. It will be on the centerline of the boat, directly under the mast and over the web of the H-beam, rather than displaced to the side like the original compression post. (I think this was a problem with the original design.).

The old compression post had made a maybe 1/4" dent in the coachroof so I plan to put a 6"x6" plate of 1/2" or 3/4" G10 between the bottom of the coachroof and the top of the new compression post to distribute the loads better. (The old post was just over 3"x3", which is not a huge load-bearing area.) I'm also replacing the 3/4" plywood that spanned the bilge walls and sat on the I-beam with a new piece made of 3/4" G10. (The plywood had delaminated and warped over time as the old H-beam warped.)

Hopefully, the new materials (SST and G10) will last a long time.

Topside, the mast step has sunk into the raised part of the deck maybe 3/8" to 1/2", so I think I need to reinforce the core with epoxy and then build the top back flush. I might also put a bigger Al or SST plate under the mast step to spread the loads into the deck better.

All of this is in preparation to equipping the boat with a tabernackle system. I want the mast step / compression post system to be strong.

BTW, to answer a previous poster's question, to get the original compression post out I jacked up the coach roof about half an inch. Kind of scary with lots of creaks and groans but no apparent damage - no cracks on top of the deck, for example. In my case, the mast was off the boat.

 

[hummingbirdbassist]

Gary and others I'm glad it worked out for you! It's wonderful what we can do without getting robbed by some large companies . The guy who did my post work is available and builds base by hand from measurements!

 

[womble]

Gary and others I'm glad it worked out for you! It's wonderful what we can do without getting robbed by some large companies . The guy who did my post work is available and builds base by hand from measurements!

Please could you supply the contact information for the guy who redid your compression block with aluminium.

Thanks.

 

[jssailem]

This looks like a sound solution to a design problem.
When you jack the cabin up and there were creaks and groans, did any of you discover new leaks along the deck-hull joint? Not a Hunter owner. With settled fiberglass and caulking compound sealant it strikes me that the movement may leave gaps in that area.

 

[Pb2388]

Interesting solutions to what seems like a common issue. For what its worth I cleaned around the I beam on my 1976 Hunter 30C and removed any loose pieces of metal, wiped with epoxy thinners, boxed in the I beam then filled the void with epoxy so that the complete I beam was encapsulated in epoxy. The final epoxy block is probably in the region of 12cm wide. While I recognise that this is not the best fix it certainly appears to be a viable option.

 

[hummingbirdbassist]

Viable works!!!!
So many times we strive for the "expert" answer to do things but many things happen between just starting and expert!!!! I'm glad your viable works!

 

[Kermit]

I'm really glad to see you back. I haven't seen you here in quite a while and was wondering what you were up to. Glad to see the project worked out for you!

 

[hummingbirdbassist]

Kermit!!!
All is well
I hadn't been on in a while because the site was not compatible or something for a while,,, getting ready to grab a Gulfstar 40!

 

[kloudie1]

Good to see ya posting again !! Hummingbird !

 

[Kermit]

...getting ready to grab a Gulfstar 40!

You're gonna need a bigger crew! Maybe my wife and I should sign on. :-D

 

[hummingbirdbassist]

You know you're welcomed anytime!

 

[hummingbirdbassist]

Thank you Kloudie