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Caulking a carvel hull below the waterline...HELP!!!


Wensum

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I've just bought :? a traditional Norfolk Broads 'river cruiser' a gaff sloop 25' + b/s built in the 1930's. The hull is of light construction, carvel planked (.5 x 4") on to light ribs and shoal draft. The Broads are flooded medieval peat diggings connected by a river system and are fresh water in the upper reaches and brackish/tidal towards Great Yarmouth. There is little or no wave action.

I need to recaulk the hull below the waterline. The caulking itself isn't a great problem, but what about the replacement stopping?

The traditionalists would have one use linseed oil putty mixed with white/red lead, pitch/gasworks tar/beeswax, but the last century must have produced better solutions.

Looking at 'sealants' on the internet presents a very confusing picture. Should one use silicones, PVA and cyanoacrylates, epoxies, polyurethanes or thiokol-based polysulphides? Sikaflex seems a possibility, but it says the wood should be 'dry', whatever that means.

So has anyone out there actually used any of these products in this way for similar waters? Any practical advice would be welcome...!

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Wensum- I highly suggest you post this question on the Woodenboat forums. You'll get LOADS of info, and there are sailors on there who sail on YOUR waters in roughly the same type of boats. Here's the link

http://media5.hypernet.com/cgi-bin/UBB/ultimatebb.cgi

try posting under the "repairs" section and good luck.

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I'm certainly not one to ask, as I've never had to re-do a boat in an authentic manner. I had what I was told was a carvel-planked boat, but it didn't have any caulk between the planks. It was more like a barrel; it relied on the tight fit of the wood and the swelling of the wood to keep everything tight. If I didn't sail it at least once every two weeks, by the third week it would have shrunk above the waterline enough that I could see light through the gaps in the hull. The it would be bail-bail-bail for an hour or so until it swelled up enough to stop leaking.

So what was this type of hull called?

Mike

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It sounds to me, Mike, like a 'strip-planked' hull. There is no caulking. Instead, the plank edges are usually curved, one rounded and its mate hollowed, so they marry snugly and are then glued, and nailed together with long ring-barbed nails. A light, almost monocoque construction but, unlike carvel, pretty well impossible to repair by replacing planks.

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From time to time I would run across a dry fit hull.

Usually a smallish vessel. The planks were fitted tight to one another with some times a strand of candle wicking set in a slight indentation or groove about one third the distance from the inside of plank. The seam would be payed with 'barrel mix' paint and the next plank edgeset tight.

A further refinement is 'Batten Seam' planking were the edge set planks are backed up by a batten on the inside with the batten screwed to both planks.

Batten Seam would be found in light weight runabout types.

Dry Seam anything from a dink type to a 30 footer.

Nothing wrong with either method as long as one realizes the pluses and minuses of them.

Woods for planking dry fit would be those that are soft and have quick takeup when set in the water. Cedars including Spanish Cedar were favoured.

Took a skilled builder to do either well.

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This boat was a racing sloop built in Copenhagen in 1936. It had a very smooth hull, lots of little shapely ribs, and not much cabin space (not much more than a Weekender, only sitting headroom) for a 30'6" boat. It had hardly any freeboard, which worked fine because I had to paddle it if the wind was down.

Nice boat though, and lots of fun to sail. It had enormous overhangs fore and aft so tacking was weird

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Oddly enough, not. Too bad, really. It was white hulled, and had the old canvas deck still, painted also. Only the little cabin was varnished. All the cockpit, rig, hatches, and such were bright also (but a lovely old patina.)

I got the boat from a fellow student at UCSD for $1800. (1984, but still cheap even then.) I think no one wanted it because it had no motor or sleeping capability, and required a slip as big as a boat which could be expected to sleep several and have a galley and head (neither of which this boat had.)

I'll see if I can dig up a pic somewhere.

Mike

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