View Full Version : Keeping carvel planking swollen

06-08-2012, 04:23 AM
I have a 1947 Danish trawler that I am converting to a live-aboard, whilst living aboard. The carvel planking on the topsides, which is 8-inch oak, has shrunk considerably since it's been out of active service. I'm intending to spline these and keep them dry but below the water line is more of a problem.

I am planning to spray at least the bottom of the hull in polyurea due to the massive gribble problem we have here which is killing the boat. I cannot afford to keep the boat out of the water for the year-or-so it will take to dry enough to spline. I am confident I can keep the bilges dry after spraying but I am concerned by the shrinkage this will cause.

Is there any way to keep planking swollen? Would a long-term wash in linseed oil do it? CPES? One interesting solution I'm looking at is a sucrose solution, as used in archaeological preservation. I'm happy for the process to be multi-year, not just a quick fix.

I'm new to this game and would really like to hear any ideas you have.

06-08-2012, 07:25 AM
Don't spline, just go out into the sea. Put some soft squishy caulking agent in the gaps , so that if your planks do swell up it can be squeezed out. If you fix any bad bits properly with new oak, and cotton etc, then it will possibly be cheaper than using some miracle goop sealant over the whole boat. (note, POSSIBLY), if you don't like the greeblies, nail some copper sheet over it. that might also be cheaper, depending on what kind of a deal you can get for copper.

Definitely DO NOT use sucrose. You will be inviting fungus. Things preserved in an archeological setting are almost always in VERY carefully controlled environments with respect to humidity, oxygen levels, light, and temperature. It's a fair guess to say that your boat will never be in that kind of environment.

If you're working on it next to the ocean, can you slosh a few buckets of salt water over the hull every other day?or wrap it in old sacks (with staples?) and do the same?

wizbang 13
06-08-2012, 08:35 AM
8 inch oak planks shrunk considerably, sure they are not rotting considerably?
the gribbles are killing the boat? sprayed polyurea?
Are you planning on EVER taking her out of the slip?
If you cannot afford to haul for a year, perhaps you cannot afford the vessel.

06-08-2012, 08:56 AM
If you cannot afford to haul for a year, perhaps you cannot afford the vessel.

It could easily be that the yard are charging $30 per day and that kinda thing adds up VERY quickly, especially if you're paying rent on an apartment and had budgeted on living aboard sooner rather than later. I seem to remember from your own posts on building your ketch (and nicely done she is) that you were pretty short on cash at times too...

Owning a wooden boat is the realization of a dream for many people, and that dream can have many forms. It's for neither you nor I to judge the quality of someone's dream based upon our own individual values.

It could be better, if Samward's trawler has good bones, to get her in the water ASAP as a live aboard by whatever method, and while living aboard he/she may be able to save up the cash for a pile of oak for new bottom planking in a year or two. Then haul her for a month and bang on the new planks.

How large is your Trawler, Sam?

06-08-2012, 09:04 AM
Sam you could consider moving your base (unless you're also working nearby, but even then it could be possible).
If you can find somewhere cheap to keep you boat on the hard for a few months you might be able to do a good job of fixing her so the bottom planking will last 50y and newly coated with anti gribble paint, you might keep them at bay for much longer, minimizing your annual maintenance costs. It's easier to keep something in a good state than it is to drag something back from a poor state or continuously fight off the rot and leaks for the next 10y.

06-08-2012, 04:05 PM
Hi Redeye, thanks for the replies. I was expecting to be lynched for mentioning encapsulation and I do understand why.

The boat is 60ft / 18m in length, 16ft / 5m in beam, and everything on the boat is big, thick and expensively heavy. The engine needs an overhaul and all of the running gear needs renewing or overhauling so we are immobile for a few years. The frames are all 5" and all in pairs every 20" or so and all that I've seen in the structure is good. She is most definitely worth saving...and she's beautiful. We are living aboard now, on the water, and have nowhere else to go. This is why I cannot afford to haul her for the proper amount of time, the only people round here with a 50-ton crane are also big working yards and are not welcoming to a couple of sea-gypsies like us!

The reason I wanted to spline the topsides is to restore some of the rigidity - just seemed like a good idea, but I'm open to suggestion. She is primarily a house that happens to be a boat and it's very unlikely she's going to get worked hard enough or regularly enough to get the tops anything but damp, so they are probably stuck in their dried, shrunken form permanently.

We are on a shoestring and wizbang is right, we probably can't afford her but we certainly can't afford to lose her. She is our home and we are committed to making this work.

As I am new to the wooden world, I'm dispassionately evaluating everything I hear - modern and traditional - with equal merit and applying it to our particular situation but restoring the hull properly is almost a non-option. There's no way I can work 2" x 8" oak planking myself and there's very few people left around here with the skills, facilities or tools. Those tend who do tend to be musuem restorers and rather inflexible. One actually laughed at me.

I could get the hull back to a working standard using laminated planks and filler but I could only afford to do it once. If something were to go wrong, or the gribbles come back with a vengeance, there'd be nothing I could do. A topcoat of polyurea is insurance for potentially decades. I've not looked into copper plate, I'll see if I can get a quote.

I know I can keep rainwater leaks out and whichever solution I use, I can add anti-microbial and anti-fungal treatments. The shrinkage is the last hurdle I have. You and my wife have both mentioned the idea of simply keeping it wet. I was thinking of plumbing in a system to pump sterile saltwater or linseed and turpentine through the bilges on a timer. Perhaps this isn't so crazy?

Lew Barrett
06-08-2012, 08:46 PM
I hesitate to say much but I am not sanguine about the prospects as described so far.

Where is the boat located? Latitude may have a bearing on the situation (is that a pun?). By the way, and you didn't mention this yourself, but we are not terribly far from the time when copper sheathing the bottom will be not only terribly expensive, but also illegal in most places. Is such a thing even a practical solution for a boat with structural needs? Keeping fresh, quality anti-fouling paint on the bottom of a type appropriate for your locale should help hugely.

Splining carries risk if the boat is truly just dried out and expected to grow back into shape with the addition of moisture. Pumping oils through an open seamed hull in the water will get you sued if not arrested in most first world nations, not a practical solution. Turning the boat in her slip is a better idea. You probably won't be able to come up with a scheme to keep her watered in the hot sun, but the usual short term solution is to tack burlap all over the affected areas and run a soaker hose through the burlap. The thing is, this is a stopgap at best, usually used to slow drying and not always effective at replacing moisture.

Maybe I missed something here......

Chip Chester
06-08-2012, 10:35 PM
Earlier today I wrote up a little post about using small-scale sprinkler heads (from garden supply -- used for window boxes and patio hanging baskets) to distribute water uniformly, on a timer, to the needed areas. Has UV rated 1/4" tube, cut with knife and press-on barbed fittings. Spray, mist, and bubbler heads, pressure compensated. I deleted it because it seemed too "out there". Maybe not. It would keep just what you want wet, on a timer. Don't know how it performs with seawater, but it's mostly plastic... Chip

06-09-2012, 12:25 AM
I'm confused. You are currently in the water and have large gaps in the topside planking? Has the boat been moved to a very hot dry area like the Arabian penninsula? If it is floating running water through the bilge will do nothing to help you- the planks will be as wet as they can get from the outside. Splining the topsides can certainly be done successfully. Some use glue on only one surface and then caulk it like it was originally but I am not an expert on splining. As for the gribbles- bottom paint is much more effective than copper plate, and about a tenth the cost. Or less. Where are you located? I'm not an expert on gribbles either, but perhaps hauling for a month would kill them, then heavy coats of bottom paint would keep them out? Keeping a boat wet when hauled can be done with the sprinklers and burlap methods mentioned. Running misting hose along the topsides may help swell them shut, but that is not a very good permanent solution. Could you tell us a little more about the current situation so we can help better? Pictures would also be great.

Max F
06-09-2012, 02:40 AM
The cheapest way to get rid of the gribbles is moving the boat to fresh water. Some big enough river if one is near your place. Keep it there for some weeks.
Then you need to put on some new bottom paint!

I was told a long while ago from a old wooden boat that got a second skin of concrete. Very succesfully.
If i remember right ,the thickness of the concrete and wire reinforcement was about 40mm.
That seems very heavy, but the boat even floated higher after all the water in the bilge tried out.
When I was told that story, they had that concrete skin for some years.
I had a look at the ship some days later. It looked good. One couldnīt see that it was covert with a thick layer of that stuff.
That seems like a very cheap and lasting but radikal solution to me. Future repairs on the skin will be much trouble though!

06-09-2012, 03:24 AM
Copper sheathing is not bad for the environment. It's not a heavy metal (technically) in fact it's an essential element for oxygen transport for many mollusks - Thats why the sediment samplers find copper in them!!! Just like finding iron in humans!

Many of our water pipes are made from copper. All this water is flushed down our drains, and in turn ends up in the sea. I'd hazard a guess that the copper loading from storm water and sewerage plants is far higher than the copper loading from sheathing your boat.
Legislators are dummer 'n a bag full of hammers.

Pretty soon you won't be able to look at the water without being sued or breaking some law. And all the while the water and sediment quality will decrease because these legislators turn a blind eye to the real causes of environmental degradation - industry and motor vehicle related pollution esp highway run off.

Sorry for the thread drift.

Sam, your boat seems pretty big, esp. if you can't easily move her around.

06-09-2012, 08:22 AM
Thank you for all your comments so far. I'll just re-summarise to answer some of the questions posed.

I have an oak hulled boat, on a tidal/mud berth in Portsmouth Harbour, UK. Boat has been immobile for 15 years.
I live in an area with a pretty bad gribble problem, lower planks have 1.5" deep holes in them.
Hauling my 60' 40+ton boat every year to re-paint is prohibitively expensive.
I'm planning on wrapping the entire hull in polurea, which is completely impenetrable to water and lasts decades.
I'm not worried too much about the topsides, they seem pretty stable.
Once coated, there will be no water in the bilges, the planks will dry and shrink and I will lose rigidity.

I would like to treat the wood below the waterline in some way to maintain it's wet/swollen size permanently.

Ideas so far:
Don't coat it - just paint it (too expensive)
Don't coat it - copper sheet it (awaiting costs, sounds expensive!)
Archaeological sucrose solution, applied internally with anti-microbial additives (a possibility)
Regular flushing with salt water, using internal network of hoses (a possibility)
Cement coating - I can achieve the same with 3mm of polyurea but have the same dry plank problems.

I've added some pictures of the topsides so you can see the extent of the shrinkage, which I'm expecting to happen below once it's coated.


06-09-2012, 08:45 AM
The only liquid I'm aware of that swells wood like water, doesn't evaporate and doesn't cause rot is antifreeze. But that's not a recommendation. I'm with the camp who argues for maintaining and using the boat as it was originally built -- caulking and lots of seawater.

Lew Barrett
06-09-2012, 12:36 PM
Your plank seams are worked over, no real caulking bevel left. I can understand why splining might seem (seam) attractive now, but making a good job of it will be tedious. Filling with an oil based compound or roofing tar and painting (or not) might be the best remedial solution. I wouldn't expect perfection and I don't think simply soaking her will be very helpful, since there are no pretty seams to come together via the usual swelling (but I'm no shipwright). That one your fingertips are on looks cupped as well but maybe that's an illusion.

06-10-2012, 02:53 PM
Spraying spandex on the bottom sounds like the end of the boat to me. Put the bottom paint on thick and you can probably get two or three years between haul outs. The bottom will eventually need replanking it sounds like, if it has very many of the 1.5" holes. If you do coat with polyurea I don't think the planks will dry out to the point of opening up. They are in a very wet environment (under water) and the humidity of the bilge alone will probably keep them tight. Has this been done before?

06-14-2012, 06:19 AM
Woxbox may have found the answer, even if unintentionally. Reading Dave Carnell's posts on this and other forums (notably http://forum.woodenboat.com/archive/index.php/t-116126.html ) makes Monoethylene Glycol seem an ideal candidate. I need to do some more work but cycling pure MEG through the bilge and back up the sides, Mary Rose style, could keep the planks nicely fattened up and rot-proofed to boot.

With regards to J.Madison post, I'm expecting to have to re-plank or extensively repair when I haul. The polyurea is a way of protecting that investment. If I can save two or three hauls in the boat's lifetime, the polyurea will have paid for itself. I'm looking at some other options but I've not found anything that offers the same potential benefits and return on investment as of yet.

@Lew, yes, she's never going to look anything other than old and worked and I don't really mind that. We've spent quite a lot of time undoing the previous owners attempt to cover all the original features with fibreglass and ply. I'm going to experiment with antifreeze/MEG to see if I can close and caulk them, if not I'll be splining.

06-14-2012, 07:09 AM
Samward -- Be aware that that stuff will leach into the water which could result in a call from the environmental police. And also, animals will drink it and die -- I hope you have no pets on board. A couple of reasons why I prefer the traditional approach.

06-14-2012, 07:36 AM
The plan would be to treat after the hull is encapsulated, which should keep it all where it's supposed to be. I have no pets and bilge access is quite controllable. The selection of wildlife in my bilge at the moment is nothing I'm going to miss too much.

I've not ruled out the traditional approach entirely, I'm still looking at bitumen and matting as a possibility - a Steam Pinnace was hauled out at my yard a while back and that had bituminous treatment 20 years ago which was still stuck fast.