When is mast step concerning?

[Marathon1150]

Beneteau put a teak block in the stringer used as the mast step. A compression post sat on top. While we were away for several months our boat watcher failed to notice that the bilge was full of salt water. The water softened the teak (Beneteau also contributed to the problem by drilling a couple of holes through the teak block to run wires from the mast to the electrical panel), and the mast step collapsed. We pulled the mast and rebuilt the step with triradial glass and epoxy after jacking up the cabin ceiling to the required height.

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[rognvald]

Simple test: use a 1/4" drill and bore a test hole through the top skin around the mast step and into the core material. DO NOT DRILL ENTIRELY THROUGH THE DECK! Check to see if the core material is wet. Check several spots around the step. If so, the only repair is to pull the mast, remove the step, and cut out the rotten core slightly beyond the saturation and re-core/fiberglass. I did that on my former 25' sailboat and when I sold it ten years later it was bulletproof. Also, when you remount the step, drill out new holes and fill with epoxy. Then, re-tap for new bolts. However, if dry, you still need to relevel deck and the right way is the same as above for saturation. Good luck, Rognvald

[GILow]

Originally Posted by Thomas1985

I have been noticing the deck around my deck step mast seems depressed, but sheds water in rain etc. The deck does not feel spongy around the mast base. No cracks in deck around the step.

I check the post and it seems solid where I can inspect. The stays all have decent adjustment left (unsure how old they are).

Is it normal for there to be some settling of the deck step? At what point is it concerning?

I would assume it settles some as wood shrinks over years? Also I would assume the deck core could compress from all the loads?

What should a person watch for in regards to deck step issues?

Everything here points to the compression post “shrinking”. Or, the compression post being driven into the keel.

You seem to be asking for advice but at the same time telling yourself and us that it’s all fine because a) the water isn’t pooling in the cabin top mount and b) the boat was built really well.

Neither are even slightly relevant. Point a) is moot as there may have been enough original deck curve to compensate for six inches of compression post contraction (my Swanson would fit this description) and point b) doesn’t matter because the boat is more than five minutes old.

And then you describe what sounds like a bloody stupid “boot” put on the bottom of the post just ideal for trapping water and rotting the base of the post.

Do yourself a favour. Stop looking for the fairytale and happy unicorn explanation and go looking for trouble. I bet you find it at the bottom of that compression post.

[SailingHarmonie]

One yard who's work I had a lot of respect for repaired compression post steps (or steps for keel stepped masts) with layers of G10 laminated with epoxy to the thickness required to replace what was lost or damaged. A totally bulletproof repair, and technically easy to assemble.

[GILow]

Originally Posted by Thomas1985

I already said I was going to check out the bottom of the post, ****tard. Learn to read…

Charming.

From the same person busily telling us how well built everything was and playing around with glasses of water.

Good luck. You sure are going to need it.

[rognvald]

Originally Posted by SailingHarmonie

One yard who's work I had a lot of respect for repaired compression post steps (or steps for keel stepped masts) with layers of G10 laminated with epoxy to the thickness required to replace what was lost or damaged. A totally bulletproof repair, and technically easy to assemble.

Real caution should be used when considering this approach since it does not address the potential problem for this common structural failure. Whether a boat's mast is deck stepped or keel stepped, determining the reason for failure is essential for a proper repair. If a core is saturated or crushed by point loading, it is this issue that must be repaired for a proper repair. Anything less is a Band aid approach for a serious issue and will not solve the problem . . . just delay subsequent failures. When I repaired the deck under the tabernacle on my 25 ft sailboat, the origin was a VHF cable routed through the deck that was not sealed properly. When I pulled the mast in the Fall and removed the tabernacle, the water intrusion destroyed the balsa core 12" beyond the cable in all directions. If I had merely used a band aid approach, the core saturation would have continued to creep beyond the 12" area and created a safety issue for a serious failure under point loading. The result would be no less for a boat with a keel stepped mast and may also reveal more serious structural issues/problems based on its location above the keel. There's only one fix for all problems . . . a proper fix. Simple.
Rognvald

[Thomas1985]

Well I got some pics after further investigation this morning…

The cabin top definitely takes a dip towards the mast, but it isn’t really a depression. It just dips down about 18” before the mast as it heads aft, but the area around the mast step is in line with the deck surrounding it. Which explains how it sheds water. It’s no much a depression as a little slope down in front of the mast.

I also am including pics from the bilge. The post really seems solid, but obviously I’d have to do some damage to see where it meets the keel as that’s pretty heavily glassed over.

I’m still concerned I might just be paranoid? I hate to go disassembling something that ain’t broke…

[OS2Dude]

My 1985 Catalina 30 was built with a wood block in the bilge encapsulated by fiberglass, then a teak box column as a compression post, then the mast step. The mast step was screwed into the deck. The block under the compression post was subject to rot that was undetectable unless you drilled into it (horizontally!). My boat had no signs of deck depression or settling, but I decided to test the block while on the hard during a refit. Drilled into the block and what looked like old coffee grounds oozed out. It was a bear to remove and replace.

[nofacey]

Looks like sloppy fiberglassing, and a perfect water trap at the base of your wooden post.
Clear the hoses, grind down the fiberglass, visually inspect wood. Believe you’re going to find soft wood; definitely something to address now.

[Pat_D]

I had a dip on deck at the mast, investigated and found wet coring under it. I was quite suprised, but there you go. Cut the top off, rebuilt it solid, found some hairline cracks in the SS compression post and a shady base at the keel, and replaced those too.

[OneBoatman]

No it is not normal for the deck to be depressed around a deck stepped mast. The compression post is not properly doing its job in resisting the load. If it is depressed with the boat at rest, it is likely considerably worse and flexing the deck transition area when sailing. You need to read these posts and investigate further. Because you find an issue at one end of the post do not exclude that the other end might also be compromised. You do need to pull the mast to do this investigation properly. If the deck remains depressed with the load removed that should be addressed independent of what you find at the base because it is most unlikely that a sunken post is pulling the deck down with nearly no loading present. Often, settling is due to the rider plate or base support being compromised where it rests on the keel. Less likely, yet possible is weakness in deck surround of the mast step as this area is normally stiffened to spread the load at the top the post. When you do the fix, use solid glass and epoxy plates, nothing should be cored in these areas, but as one poster mentions, do not overlook that the builder may have used a wood glass sandwhich at the base, a no no.

[Thomas1985]

I’m making plans to have the mast taken down and boat hauled back to my sheds so I can investigate/ rebuild this fall and winter. After a lot of thought I’m in agreement it about has to be that base…

I already knew I was getting in to some pretty extensive deck repairs this winter so I’m glad I started noticing this before I did all that work.

I think I’m going to also use the opportunity to do some mast restoration while it’s down.

Gonna be a busy winter

[Thomas1985]

Step 1 down… mast is down on my deck waiting to placed on a trailer when I haul out.

One wire had no disconnect so I cut something…