Barge bilge

[AKocgy]

Hi:
My apologies for the length of this post, but I thought I would try to provide as much detail as possible up front. I’m looking for some advice on a floating home I’m renovating that’s located in Southcentral AK. It’s basically a small house built on top of a fiberglass over plywood salt barge that was once used in the herring fishery here. The hull of the barge has stout 4x6 frames on the bottom that are bolted to plywood and timber frames on the sides of the hull. A lot of the bilge isn’t accessible, it has a plywood floor screwed down over top of the frames (and laminate flooring over some of that), but the frames on the sides are open, so I can see (and reach) the inside of the hull all around the edges, and can peer down between the frames if I stick my head down there. The entire inside of the hull has been covered with blocks of solid foam insulation between the frames: white styrofoam (the crumbly stuff that’s easy to break apart) on the bottom, and pink extruded polystyrene on the sides.

When crawling around before I bought it, I inspected every bit of hull I could access, pulling up the styrofoam to check the plywood underneath. In general it looks pretty good, though I found a small amount of water in one corner, and a few wet spots where the wood was blackened and a little soft when I tested it with my screwdriver, though it looks like most of the damage is to the top ply. I’m thinking that placing the styrofoam on the bottom of the bilge wasn’t a very good idea- it would trap any water that got down there between itself and the hull, and provide a pretty good environment for mold to grow. It’s good that the barge previously stored salt, that probably slowed down the process considerably.

I have several small boats and spend a lot of time at sea, but this kind of construction is new to me. I’ve spent a lot of time searching around books and the internet looking for some resources on what to do about this, and it hasn’t been too very fruitful- this isn’t a very common scenario, but the hull is a glass over ply hull like any other. So I thought I’d throw out what I’m planning to a couple of forums and see what you all think. My plan so far is this:

1. Take up the floors, remove all the styrofoam on the bottom and assess the rest of the hull.

2. Remove the insulation on the sides of the hull to inspect it and see if I can find the source of the water I found. Reinstall the insulation on the sides, but only from the waterline up, to help buffer the temperature in the bilge, the idea being that air temperature changes a lot, but the water temperature doesn’t.

3. Put in a new floor, with insulation on the underside of the flooring (I’ll probably just glue all that styrofoam to it), leaving the inside of the hull bare. I’ll engineer the floor so that I can get access to the bilge from time to time to keep an eye on it.

4. Seal up the frames on the sides with plywood and caulk, with insulation on the bilge-side surface of the plywood. In effect, seal off the interior of the house from the bilge and insulate the “house” part, not the bilge.
5. Install a vent at one end of the hull (there is an arctic entry that is unheated, but is enclosed and warms up when the sun’s shining) and a fan on the other, that I can run periodically to ventilate the bilge and help keep it dry.

I’d greatly appreciation anyone’s feedback, comments or suggestions. And finally, one thing I haven’t been able to find out much about is what do about the mold that is already there- most of the wood boat literature I’ve read talks about replacing the wood, but that’s not an option here. Is there any way to disinfect the wood to kill and/or remove as much of the mold as possible? I’d like to get the bilge as clean and dry as possible before I put anything on top of it again.

Thanks!

[rwatson]

....... one thing I haven’t been able to find out much about is what do about the mold that is already there- most of the wood boat literature I’ve read talks about replacing the wood, but that’s not an option here. Is there any way to disinfect the wood to kill and/or remove as much of the mold as possible? I’d like to get the bilge as clean and dry as possible before I put anything on top of it again. !

"talks about replacing the wood, but that’s not an option here."

Whats the reason its not an option ?

I don't think you need to removed all the wood panel, just far enough down to get to sound wood

[PAR]

Typically, this type of construction isn't intended to be serviced. It's intended to live it's life, then die, usually from a slow, lingering, rot laden existence.

You can disassemble the barge potion, but you may be correct in that it "may not be an option". I say this for several reasons: the presence of mold, rot and inappropriate foam. The foam traps moisture against the wood (as you surmised), promoting rot and mold. It also absorbs moisture, making the boat heavy and offering a continuous supply of more moisture to feed the rot and mold. Boats built like this usually have heavy scantlings, much of which is considered "sacrificial" in nature. They know damn right well, what will happen as a result of the techniques used, but make it big and stout, so it takes a while to get "eaten up" by the various things that will attack the wooden elements.

The typical course of action is to strip out the foam and extraneous wooden elements that are past saving, dry the hull as best as possible (on the hard) then rebuild/replace the affected pieces, seal up the boat tight, paint and continue with the interior as you planned.

This is a huge undertaking and not one for the weak of heart, as you'll open her up and find all sorts of problems. Rot is an insidious beast and where you can see it, there's 10 times as much that you can't see, though once you tear into stuff, you'll find it easily enough.

To me, it sounds like you need a serious inspection by a qualified surveyor. This will let you know the real extent of the troubles your barge has and if the surveyor is good, he'll include a possible plan of action for fixing her.

The foam blocks where very probably placed in her, in an attempt to prevent sinking, because she leaks like a bottomless bucket. The bottom line is you need a full assessment and you'll likely have to renew a substantial portion of the structure to make her sound again. Since she was never intended to have this done, the tasks involved will be daunting to say the least. In the end, of course based on the surveyor's report, it may well be much cheaper to build a new hull shell and transfer as much as you can from the old gal to the fresh hull.

[AKocgy]

Thanks rwatson and PAR,

rwatson: Replacing the plywood in the hull isn't an option because it's fiberglassed on one side, and has the frames (with the house sitting on top) on the other. I can get at the wood between the frames though.

PAR: The hull isn't that bad, in most of the places I checked it's dry and solid. I suspect that what has got in might be rainwater (Southcentral AK is an orographic rain hotspot). There's just a few trouble spots that need attending to. We don't have a surveyor in town presently, getting someone up here and doing a full survey would probably cost on order of a quarter of what I paid for the thing. The foam blocks are not floatation, they are 1.5" sheets that are laying on top of the flat bilge.

[Saildude]

How about using a dehumidifier to help dry the bilge? Don't try and make it desert dry but just bring the humidity down for the SE standard of what seemed like 90% many parts of the year (and don't get me started on the months long lead colored skies) - I have several friends that use dehumidifiers on their boats here in Seattle to reduce the moisture and stop the mold.

That should get the extra water out of the hull which would be a good start.

[Stumble]

Par as usual is probably right about what needs to be done to return the boat to 100%. But I am guessing that that is not the goal of the owner.

I would think that simply removing as much of the foam as possible combined with a serious effort at eliminating the current mold/rot would at least prolong the lifespan of the boat. No it won't be perfect, but it will help.

I will also second Saildude's suggestion of getting a dehumidifier or two in the hull, but first you have to find out where the water is coming from. If the water is just a little bit of rain seeping through, then you need to find where it is seeping through from and end it. If it is working in from the hull, that also needs to be eliminated. Only then will a dehumidifier or two really start to pay benefits. Though in my experience no boat in the world can be too dry. Crank those things to high and let them suck the boat as dry as they can.

[PAR]

Sweet water is the killer of most boats, not sea water. Rain collects at the lowest point and the path it takes, as well as where it eventually lives in the bilge, will be continuous problem areas.

The bilge should be dry if the boat is properly sealed up. This means weather decks shed their water over the side and the hull is tight. Those that say a wooden boat always has a wet bilge, haven't been in a boat with well caulked seams or intact sheathings. I have a 37 foot 50 year old cruiser that until it sprung a butt block not long ago had a dusty bilge, since I repaired the hull, replaced the garboards and recaulked 5 years ago. I'll haul out sometime this summer and fix the damn butt block and she'll be tight and dry again. Other then repairs, she has her original cedar planking and has had an easy, well cared for life.

[rwatson]

Thanks rwatson and PAR,

rwatson: Replacing the plywood in the hull isn't an option because it's fiberglassed on one side, and has the frames (with the house sitting on top) on the other. I can get at the wood between the frames though.

.

That is even better if it is fibreglassed on the outside. You can grind the plywood down from the inside without mucking up the outside surface. If you can remove big sections on the inside, you can epoxy replacement panels using a lot of epoxy filler on the inside surface, and around the edges, and epoxy and fibreglass over the repaired section.

Even if the frame is in the way, cut out a piece of frame- and you can replace it after the hull material is fixed.

You only want to replace one frame at a time of course, to prevent the whole hull distorting or collapsing.

Of course I say this with no knowledge of the accessability to the guts of the boat. The whole business sounds like a potential nightmare.

It could be that Pars idea of building a new hull and putting your superstructure on it might be cheaper if you have to pay for labour.

[AKocgy]

Good idea rwatson, thanks. I started digging into it this weekend, everything is accessible or can be made so. In general the hull's looking pretty good, I found one leak under the front door with some soft wood below it, I'll be able to get that wood out and put in some new after I've patched the outside.

There's been a lot of used boats in my life, every one has its little surprises!

[Aharon]

AKocgy is talented with words and made a good description of the problem, but pictures would have cut the words by thousands - beside, I love boat pictures!