What kind of rot is this?

[jrusk]

Hello All-

I have a 42' 1956 Chris Craft Constellation. I have been noticing some kind of deterioration along the ribs in the engine room. Photo attached. What is causing this and how to prevent? The boat is kept in a covered slip in the water year round in Virginia. There is no fresh water penetration into the affected area. There is no other rot in the usual places, around windows or decks. The boat is generally in top condition.

I've owned wood boats in the past, so I am familiar with dry rot caused by fresh water. Usually, the entire wood piece is permeated with the rot, and an ice pick can be pushed all the way in. The rot in this case is different. It's only on the surface, and appears to be a kind of "shredding" or "fuzzing" of the outer surface of the wood. The layers below are solid. Therefore rot caused by water or condensation is not my first thought but I'm wondering if it might be caused by some kind of electrical condition - electrolysis, or stray DC current grounding out, or even neighboring boats putting out current into the water, etc. but I need an expert's advice. And it has occurred quickly - over the course of a winter. Any thoughts about this?

Many thanks

 

[FoxtrotCharlie]

Is that a marine/mahogany plywood hull? I once owned a 1965 28' CC that had the ply hull - CC used it between lapstrake and fiberglass eras. Could it be from the glue from the layers of ply?

 

[sdowney717]

If the boat is in salt or brackish water, it is a weeping salt rot.
The water slowly weeps through that area, dries and leaves behind salt crystals which fray and cut the wood fibers.
If that is true, it is a very very slow leak. If you can keep the moisture from coming through the wood and drying, then the problem will cease.

I would scrape off the loose fibers, and seal it with epoxy or paint.
If you scrape it down, and it is damp, try drying first with a heat gun, before sealing it.

I don't see any thru hulls around that fuzzing wood, so I doubt it is electricity.

 

[Panacea123]

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[jrusk]

Thanks for the replies. There's no plywood, so that's not a factor. But sdowney, your ideas are very interesting and could be the answer. The boat is in brackish water, off the Potomac. The damaged area is right at the waterline, actually a couple of inches above, but water can be seeping through and doing what you describe. If it was scraped down and sealed with epoxy on the inside, do you think that would stop the process, even if there was still some seepage? Or would it be necessary to find the infiltration point on the outside and seal that? The paint on the hull is 7 years old and due for renewal - doesn't look too bad, but I'm wondering if this could be a factor in allowing water to infiltrate. Thanks so much.

 

[DHeckrotte]

Post on the WoodenBoat Forum. Email Dr Jaegels at WoodenBoat.

Examine the rest of the hull for similar appearance.

How long has it been since you last looked there?

 

[sdowney717]

Thanks for the replies. There's no plywood, so that's not a factor. But sdowney, your ideas are very interesting and could be the answer. The boat is in brackish water, off the Potomac. The damaged area is right at the waterline, actually a couple of inches above, but water can be seeping through and doing what you describe. If it was scraped down and sealed with epoxy on the inside, do you think that would stop the process, even if there was still some seepage? Or would it be necessary to find the infiltration point on the outside and seal that? The paint on the hull is 7 years old and due for renewal - doesn't look too bad, but I'm wondering if this could be a factor in allowing water to infiltrate. Thanks so much.

Yes, it will stop it completely, if you seal the inside wood surface.
Preventing the weeping water intrusion and then it drying on the surface to form salt crystal which cut the wood, is the ultimate goal.
On a haulout, look at the exterior, you may need to recaulk. You may also have a cracked plank.

 

[Nomad Willy]

There's only one kind of rot. rot.

What you have is not rot but some kind of critter like ants.

 

[CaptSteve53]

Critters like BORER?

 

[Nomad Willy]

Steve,
Yes maybe flying ants.
just a guess.

 

[swampu]

I had a similar looking "rot", my hull is Cypress. It ended up being a slow leak from a keel cooler bolt that worked it's way out and broke. After the trip to the yard they replaced all the bolts and now the problem is fixed, I also had a few bad fiberglass repair jobs that were leaking very slow. All fixed and zero moisture invasion. We are finally putting another coat of paint on this week.

 

[HiDHo]

Looks like some type of wood fungus. You can remove the loose fibers and treat it with anti-freeze to kill the fungus. Let the ethyl glycol saturate the wood fibers then rebuild with epoxy.

 

[gaston]

Agree its a fungal rot it can be stopped and repaired using "West Systems " epoxy buy drilling 100s of small holes and injection with epoxy in a syringe when mixed correctly it will have the consistency of water.
This will penetrate the timber and form a hard workable area .

 

[Old deckhand]

Not all antifreeze is ethylene glycol. In my experience the 50/50 mixture works as well as 100%.

 

[kev_rm]

Critters like BORER?

https://en.wikipedia.org/wiki/Eastern_carpenter_bee

 

[Lepke]

If you seal a leak passing thru wood on the inside, you are basically making a sponge that is always wet internally. You need to solve the leak. It's position could be a drip from the deck. Water can travel a long way downhill, thru seams, along framing, etc.
If it's from a fresh water leak you'll get dryrot.
I once chased a leak over a couple years in a wood boat. It started on the flying bridge, went down inside the wall of the wheel house and in a plank seam to drip in the forward, below deck area.

 

[OldDan1943]

May I suggest you contact your nearest Ag agent. Invite him to the boat to look at it. Free
2nd option, Invite a pest control company to come and look at it. Just might have a small charge.
Looks like caked dirt on the left of the pic. That would suggest termites.
Obviously, you must remove this wood. There is no structural support and it may have an active colony.
The next option is rot.
Considering the options, I would start with the nearest Ag Agent. FREE
Work from there.

 

[Scratchnsaw]

That's typical in wooden boats and the lack of air flow. You see that a lot in engine rooms on those older type boats. What type of venting do you have? Is there engine room vents over the area that's showing? You may need to add some additional vents, or check and see if any vent that allows air to flow into the engine room is fully clear. Sometimes when they put the old fashion copper screening, over time some corrosion will close up the screening too.

 

[Lepke]

Arsenic and copper solutions applied separately will kill all rot and any bugs. Online from chemical companies that sell small quantities. Untreated rot will continue to spread to any other touching wood and maybe by air to additional places.
After arsenic/copper application the wood is considered hazardous waste. Why we cut more trees rather than have wood preservatives that actually work. The US use to have a testing station in Panama. Wood treated with the above items was placed in a jungle area (many years ago) half in the ground along with wood with other treatments and no treatments. Untreated wood was totally gone in 3 years. The copper/arsenic treated wood was still in excellent condition 50 years later. I read the report in the mid 70s - about the time the EPA was making it illegal. Now borate, a salt, is the only approved marine wood preservative I know of. I use it in the bilges of my wood boat but only after applying something that works.

 

[OFB]

Not much will survive after a brushing of acetone.

Then a diluted application of epoxy acetone over.

Its painted with oil based base paint from the pics.
Try a fire resistant paint over effected area . IMO

Make sure its well ventilated for any application of what ever and where a breathing apparatus ( cheap IMO )

 

[78puget-trawler]

I know this is a year old but the first thing I would have asked the OP is did he look up to see if what was going on was in fact above, because it looks like debris falling down and piling up on the batten seams.

 

[psneeld]

Not positive ..

But here is an explanation of salt damage to wood...

Techline_06-2011-001.pdf

 

[78puget-trawler]

As noted in this thread there could be any number of reasons for this. And while no thru hulls are present in the picture, it could still be a stray current issue. Zincs could be exhausted, could be over bonding, a common problem in wood boats. Could be from something as simple as an electrical cord laying in the wrong place. Hull planking on a Chris is fairly thin, under an inch even on a big one, so there isn't really a lot of wood between inside and out. Saturating the area with epoxy will be a temporary fix but the wood will likely need to be replaced. Its pretty hard to diagnose such issues from one picture. I worked on wood boats as a shipwright for nearly 30 years and I cannot say with certainty what caused this from whats seen here.

 

[ORIF]

I have 2 wooden supports for my battery tray which have the same appearance and description. The wood is completely dry but the outer surface is shredding. Under that is hard wood. Location is the engine room.
Planning to seal with a penetrating epoxy.
The above suggestions of hot environment coupled with water and salt exposure and possibly electrolysis may be the only explanation.
Still curious if anyone has an explanation or experience with this type of decay.

 

[sunchaser]

Battery acid will rot wood.

 

[ORIF]

quite possible

 

[Northern Spy]

Big time. Noticed my plywood starting to delaminate under my battery bank just the other day.

 

[Art]

Big time. Noticed my plywood starting to delaminate under my battery bank just the other day.

Sounds like a marital problem!