The Rusty Compression Post Problem

[Intrepid-II]

I have finally decided that it is time to deal with the rusty compression post on our 82 Hunter 30.
I don't want it to crumble and collapses creating an even bigger problem.

I know several of you have already successfully dealt with this problem so I am looking for advice from your experience.

 

[David in Sandusky]

Looks like a tough problem to me!

My ideas include:
- Use a hydraulic jack (or two) at the side(s) of the post to take the load while you work on the post.
- Hammering a custom cut steel or aluminum bar on the side could perform a similar backup function.
- Then, I would simply clean off the rust on the pipe. While it may look scary, rust increases the volume of the iron in the post, and the existing post may well be able to do the job after you clean it off.
- Applying a rust resisting coating would finish the job.
- If I were still not confident in the pipe, I would consider welding helper bars on either side of the pipe.

I would defer to others who have replaced the pipe for advice on that solution. If that was my plan, it would involve pulling the mast to relieve the compression stress on the hull from the stays as well as hydraulic jacks to maintain the position during the replacement.

 

[Intrepid-II]

Looks like a tough problem to me!

My ideas include:
- Use a hydraulic jack (or two) at the side(s) of the post to take the load while you work on the post.
- Hammering a custom cut steel or aluminum bar on the side could perform a similar backup function.
- Then, I would simply clean off the rust on the pipe. While it may look scary, rust increases the volume of the iron in the post, and the existing post may well be able to do the job after you clean it off.
- Applying a rust resisting coating would finish the job.
- If I were still not confident in the pipe, I would consider welding helper bars on either side of the pipe.

I would defer to others who have replaced the pipe for advice on that solution. If that was my plan, it would involve pulling the mast to relieve the compression stress on the hull from the stays as well as hydraulic jacks to maintain the position during the replacement.

Thanks, yes relieving and supporting the load during the work is part of my still developing plan for this project.

 

[MikeHoncho]

I posted about my replacement about 5 years ago. It isn't hard, you just have to plan it out and prep for a mess if you need to grind out glass. I had too. The biggest challenge was bringing everything you need to the boat. Second biggest is coming up with space to jack up the bulkhead ceiling wile keeping space to work. I used 4x4s and bottle jacks (make sure you remember to loosen your rigging). I would not do the work with the compression post in place. Remove it and inspect. I ended up adding a second compression post to mine due to the mast step not being centered on the compression post. I added a carbon fiber plate to the ceiling that spanned the whole area of the mast step, re-installed the original compression post then added another infront of it with a gap for the bathroom door (sliding) to pass between them. The combination now supports the whole area of the step. I replaced bilge step, which was original I-Beam, with composite material and have been very happy with it, no issues and it isn't going to rot again.

I-Beam Replacement Project Summary

I bought the boat 3 years ago knowing the I -Beam was needing replacement. I have been battling a water leak from the mast base into the cabin via the mast wires. Knowing the water isn’t just going into the cabin but also into the core, I needed to address it. Both required removing the...

forums.sailboatowners.com

 

[Intrepid-II]

I posted about my replacement about 5 years ago. It isn't hard, you just have to plan it out and prep for a mess if you need to grind out glass. I had too. The biggest challenge was bringing everything you need to the boat. Second biggest is coming up with space to jack up the bulkhead ceiling wile keeping space to work. I used 4x4s and bottle jacks (make sure you remember to loosen your rigging). I would not do the work with the compression post in place. Remove it and inspect. I ended up adding a second compression post to mine due to the mast step not being centered on the compression post. I added a carbon fiber plate to the ceiling that spanned the whole area of the mast step, re-installed the original compression post then added another infront of it with a gap for the bathroom door (sliding) to pass between them. The combination now supports the whole area of the step. I replaced bilge step, which was original I-Beam, with composite material and have been very happy with it, no issues and it isn't going to rot again.

I-Beam Replacement Project Summary

I bought the boat 3 years ago knowing the I -Beam was needing replacement. I have been battling a water leak from the mast base into the cabin via the mast wires. Knowing the water isn’t just going into the cabin but also into the core, I needed to address it. Both required removing the...

forums.sailboatowners.com

Thanks, I found your old post and reviewed it as I was researching this project. Not looking forward to all the time laying on the floor with my arms in the bilge and the tool I need in my home 30 minutes from the boat. My 82H30 looks like a different setup. I don't have the I-beam and there is 2" square tubing that runs under the floor like a rib and has another 2" welded mast support that runs down to the top of the keel. Yes, there will be cutting and grinding and shop vacuuming fun to remove the rusty 2" steel tube and the mess that it is sitting on. Looking at replacing it with G10.

 

[Dalliance]

Hunter used the infamous I-beam in the H30 bilge through 1980. In 1981 they switched to the rig you and I have in our ‘82 H30’s. The 2x2 steel tube rig has a vertical leg with a base plate in the bilge welded to a matching 2x2 steel tube transverse rib that extends up to threaded stainless steel tension rods that go up to the chainplates. The vertical tube and base plate down in the bilge are particularly vulnerable to corrosion. Fortunately, the walls of these steel tubes are a full 1/4” thick.

In my case, I was seeing corrosion at the underside of the base plate and the lower 1/3 of the vertical tube, but the transverse rib was fine. Not knowing at the time just how thick that tube actually was or how much of it was left, I decided in 2021 to cut out the bottom half of the vertical leg and replace it with a new corrosion proof base of high density G-10 fiberglass. I did this on the hard with the mast unstepped.

This link should get you to a more detailed description I posted back in 2022. See response #7.

Houston, we have a Problem - H36 Compression Post

Well, I think I have officially joined the club. Apparently a club that seems to be reserved more for H30 owners, but nonetheless, it's a club with many members. We have a 1982 H36, owned previously by my folks. The old man made many upgrades and took tremendous care of this vessel. One...

forums.sailboatowners.com

 

[Intrepid-II]

Hunter used the infamous I-beam in the H30 bilge through 1980. In 1981 they switched to the rig you and I have in our ‘82 H30’s. The 2x2 steel tube rig has a vertical leg with a base plate in the bilge welded to a matching 2x2 steel tube transverse rib that extends up to threaded stainless steel tension rods that go up to the chainplates. The vertical tube and base plate down in the bilge are particularly vulnerable to corrosion. Fortunately, the walls of these steel tubes are a full 1/4” thick.

In my case, I was seeing corrosion at the underside of the base plate and the lower 1/3 of the vertical tube, but the transverse rib was fine. Not knowing at the time just how thick that tube actually was or how much of it was left, I decided in 2021 to cut out the bottom half of the vertical leg and replace it with a new corrosion proof base of high density G-10 fiberglass. I did this on the hard with the mast unstepped.

This link should get you to a more detailed description I posted back in 2022. See response #7.

Houston, we have a Problem - H36 Compression Post

Well, I think I have officially joined the club. Apparently a club that seems to be reserved more for H30 owners, but nonetheless, it's a club with many members. We have a 1982 H36, owned previously by my folks. The old man made many upgrades and took tremendous care of this vessel. One...

forums.sailboatowners.com

Thanks for the point to your post. I already decided to use G10 after considering using other materials. I plan to cut the square tube about 2" down from where it is welded to the rib. I will use cardboard and plywood to make templets at the boat and then take them home so I can cut the G10 in my shop.