Sagging deck by the companionway coaming

[NI_Boating]

Hello All,
I have a new to me 1994 Hunter 26. I have come to realize that the deck and coaming are sagging to the starboard side of the companionway. I assume this is because of a rotten wood core. See the attached pictures. There is a significant sag.

- Yes, the first thing I am going to do is to reseal all the deck hardware and mast to deck joint.
- I did a pretty good tap all around the boat before I bought it. It didn't and still doesn't sound hollow. (yes, maybe a survey would have been worth it)
- There may be a little more flex when walking on that side of the deck versus the port. I don't know if the head walls support the port side or if it is compromised on the starboard side. Nothing feels squishy.
- The coming feels solid when I push up from below.
- There is no fiberglass cracking.
- The inner cabin lid is all one-piece fiberglass. It is not bonded tightly to the roof in that area. It is a little looser on the starboard side than other areas. I am not sure if it is supposed to be structurally bonded or if that is more of a cosmetic skin.

Has anyone else experienced this?

Does anyone have details of how the deck is constructed? I found online references stating that the deck fiberglass is structurally bonded to marine-grade plywood. This seems less prone to rot than balsa.

My next step is to check out the condition of the core when I remove hardware to re-bed. A lot of that hardware is attached to aluminum plates embedded in the core, so I don't know how much I am able to see.

After that, maybe I need to do exploratory drilling. I would like to understand what the structure is first.

I have found some drawings and pictures of other parts of boat construction. This is a great group sharing those. But I haven't found anything specific to the deck and coaming construction.

 

[dmax]

Before you drill any holes, borrow or buy a moisture meter - Ryobi's for $50 will do - and determine if there's high moisture/rot in there. You should be able to determine the extent of the problem. End-grain balsa is better than plywood with regards to rot as moisture travels along the grain (balsa's grain is vertical).

 

[NI_Boating]

Before you drill any holes, borrow or buy a moisture meter - Ryobi's for $50 will do - and determine if there's high moisture/rot in there. You should be able to determine the extent of the problem. End-grain balsa is better than plywood with regards to rot as moisture travels along the grain (balsa's grain is vertical).

Thanks dmax. I will try that. I didn't realize moisture meters would work through the fiberglass. Your suggestion prompted me to research the pinless meters that get all fancy like that.

 

[Don S/V ILLusion]

Your thought about “the first thing you will do is resealing all deck hardware” won’t solve the problem and won’t help isolate the extent of the problem. As suggested, use a moisture sensor but practice first as it can easily be misunderstood.

 

[Ralph Johnstone]

A lot of that hardware is attached to aluminum plates embedded in the core, so I don't know how much I am able to see.

A cautionary note on the SS screws in the Al plates. The are the mother of all creation to remove as the two will corrode together over the years. A month of penetrant oil MAY get one or two out. If you do manage to unscrew the screw out of the Al plate, the threaded hole in the Al will be toast. I had to provide ungodly cut out holes under the two bow cleats in order to install new SS machine screws with washers and SS nuts. Each new machine screw was a project unto itself. If there is any hope in hell that a fitting is NOT leaking, avoid unscrewing if at all possible.

Good luck with it.

 

[hunter240]

Agree on all the above concerning AL plates and ss screws. Had the same problem with bow cleat. Used extractor drill bits to get them out. Even then a real PITA. Been following this website since 1998 and saw or heard mention of a sag like that.

 

[Rick Webb]

I am 99.7% certain that there is no balsa or plywood in these boats.

Is there cracking in the gelcoat around the sagging?

 

[shemandr]

. I am 99.7% certain that there is no balsa or plywood in these boats...

I don't understand. Are you saying the deck isn't cored or are you saying the deck is cored with another material?

 

[NI_Boating]

There is no cracking in the gelcoat around the sagging.

I have not been back out to the boat to take the moisture readings yet. I will report back when I do.

 

[Rick Webb]

With no cracking of the gelcoat, I'm inclined to believe that is just how the boat was made or there was a repair done that turned out not quite straight.

I am all but 100% positive the only wood in these boats is the trim in the interior and the hatch covers under the cushions inside the cabin.

 

[Davidasailor26]

ith no cracking of the gelcoat, I'm inclined to believe that is just how the boat was made or there was a repair done that turned out not quite straight.

That was my first thought too. If nothing is cracked, nothing feels soft, and the sliding hatch isn’t binding, I’d assume it came out of the mold that way.