What kind of rot is this?

Discussion in 'Wooden Boat Building and Restoration' started by John R., Aug 28, 2017.

  1. John R.
    Joined: Aug 2017
    Posts: 3
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    Location: Callao Va.

    John R. New Member

    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. The deterioration is now in several confined spots, all in engine room, at least that's what can be seen. There is no other rot in the usual places, around windows, decks, etc.
    Thanks so much.
     

    Attached Files:

  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Looks like wet rot. It is actually the sugars in the wood fermenting. Yeast is what causes that and you should smell alcohol.
     
  3. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    I frequently smell alcohol when I'm on my boat.
     
  4. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    You might try this for all the various reasons stated. I've never used it on a boat but I use it on the house and buildings.

    Chemotherapy for Rot http://www.angelfire.com/nc3/davecarnell/rot.html
     
  5. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    Ha! You probably don't need a preservative though for that.
     
  6. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    Has to be water ingress of some kind associated with that, or at least constant damp from condensation.
     
  7. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

  8. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Moored and berthed craft suffer this frequently. The most common causes are the boat is locked up with little use and worse, little ventilation, so condensation forms, evaporates, forms again, etc. in a repeating cycle. The solution is careful cleaning, sterilization and good ventilation afterward. Those pieces look badly beaten up so some repairs will be necessary. Dirt is a compounding concern. Battens and stringers tend to collect dust and dirt, which trap moisture from condensation.
     
  9. John R.
    Joined: Aug 2017
    Posts: 3
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    Location: Callao Va.

    John R. New Member

    Thanks for the replies. I've owned wood boats in the past, so I am familiar with dry rot caused by water penetration. 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. So rot caused by water or condensation was not my first thought. My first idea was that it was caused by some kind of electrical imbalance - electrolysis, or stray DC current grounding out, or even neighboring boats putting out current into the water. Any thoughts about this? Thanks.
     
  10. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Nope, it's caused by condensation on the pieces themselves and the usual ambient humidity levels within the boat. This can happen on trailer stored boats if stored well sealed up, under tarps, unventilated shrink wraps, etc. When a boat is berthed, the humidity level is much higher generally, so ventilation is key. Well placed "Nicro vents" can help a lot, which can be placed just about anywhere, including in covers, tarps, shrink wrap, dorade boxes, hatch covers, etc.

    The repair usually entails scraping the offending area down, until you're absolutely sure you're down into solid, unmolested wood, treating the area (one of several chemicals and/or coatings) then ensuring good ventilation. Often you'll have to remove 10% or more of the piece that's seen this damage, so consider scabing in a reinforcement piece, over the area, to restore its integrity.

    So, how well ventilated is your boat? How often does it get taken out for a good run at speed?
     
  11. John R.
    Joined: Aug 2017
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    Location: Callao Va.

    John R. New Member

    Thanks so much for the thoughtful reply. You're making me feel better that there's not a major electrical problem to figure out. To answer your questions, the boat is stored for 9 winter months in the covered slip with no one on it. Thats when the damage occurred. I live aboard during the summer. I've owned it for 10 years, and had issues with mold forming throughout the cabins during storage, so I've settled on keeping it sealed up pretty tight with a dehumidifier running for a few hours a day for those 9 months, and have not had any mold. I did previously try leaving some windows cracked open but the mold continued. The engine room is also sealed up, but the dehum does not reach there. I can try leaving open the engine room vent ports this winter and see if it makes any dif.
     

  12. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Natural ventilation can work, though the boat needs to have entry and exit points looked at, so you can get good flow. Forced ventilation is better and can get into spaces that would otherwise not receive much. I like to place the boat in a negative pressure environment, so the fresh air is sucked/drawn into the spaces, then exhausted out vents. Others like a positive venting arrangement whereas the intake air is pressurized (fans) and pushed through the boat. I've found these systems tend to just conduct flow along the least paths of resistance, which means some places aren't well vented.

    The natural flow of air isn't as simple as it might seem to figure out.
    [​IMG]
    Assuming this is your boat, the natural flow will be through the forward hatch and ports, through the cabin and out the aft end of the cabin and bridge area. Underway, the flow this reversed, flowing forward from the aft cabin bulkhead, through the cabin and out the hatch and forward ports. To place this boat in negative pressure, I'd place a couple of Nicro vents in the aft engine room vent holes, so they blow out. Next I'd insure the cabin was sealed up (closed cabin door), but everything else was opened (lockers, cabinets, cushions removed or standing on edge, etc. With the forward hatch and ports just cracked open, enough "draw" to get good flow. The only place I'd worry about might be under the aft deck and some areas aft of the engine compartment(s). Additionally, you could install some Nicro's in the forward ports and/or hatch, blowing in, to help improve flow.
     
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