stuhaynes
Well-Known Member
I had a real problem on Cygnus vedrae with water leaking behind the gunnel quadrants, where the horizontal gunnel meets the vertical superstructure. As you may know from my other posts Cygnus is mahogany on oak circa 1950.
I've attached a jpg that shows a cross section of the gunnel at its meeting point with the superstructure, where you can also see an end-on view of the hardwood quadrant. We had always had problems with water getting in somehow, past the quadrants. I'd had 'em off, sealed them and then in desperation completely replaced them, but with only 'some' success.
I've now cured the leaks thanks to Stuart and Sheila, owners of Highlander, an ex Whitby lifeboat whose original name was The Robert and Mary Ellis. I believe that she was launched in 1909 and was a rowing boat.
When she was retired [I think in 1937] she went into private hands and was given an engine, and eventually a cabin and all the rest. She's still looking great.
Having a drink with Stuart and Sheila in the yacht club, Kath and I mentioned our frustration with the leaks. Sheila told us about their self same problem and invited us to their boat to see how they'd fixed it.
The following sounded a bit 'iffy' to me, but when I saw theirs I thought, why not...
It comes down to buying the thinnest lead flashing [about 1mm], the stuff you see on a house where the chimney meets the roof. It's very cheap and every builders merchant stocks it. Cut to a suitable width with a craft knife and a straight edge. Use a router with a 6mm bit and gouge a slot, in our case 40mm above the gunnels. Bend the lead, it's dead easy, to the shape shown in the jpeg. The idea is that the lead goes fully into the slot, down the vertical face and under the quadrant. Before placing the lead fill the slot and the area where the lead is going to sit with Sikoflex. With the lead in place, attach the quadrant in the normal way with stainless steel screws. It's important that the quadrant is fitted before the Sikoflex cures, so do the job by quadrant length.
It is important that you 'dry run' the lead, make sure it's shaped and fits. when you fit the quad and screw it down you'll find that the lead may move. Use a light hand, a block of flat wood and a small hammer to get the flushest fit you can, this is why the mastic should still be uncured.
We were limited by the router we used which is why the slot we cut was 40mm above the gunnel. The quad is 25mm high so the lead joint is above it. I needn't have worried, nobody even notices that it is there once finished. I can also say that this is the only application where mastic has actually worked for me on high humidity mahogany.
I'm sorry if I've made a dogs dinner of explaining this but I can assure you that this really does work. If you're unsure, knock a couple of bits of wood together and try it as a dry run.
Stu and Kath.
Our Cobb website
The jpeg is virus free. I drew it myself on autocad, a program I've used for 2 years without problem. I also ran it through my antivirus program to be certain.
I've attached a jpg that shows a cross section of the gunnel at its meeting point with the superstructure, where you can also see an end-on view of the hardwood quadrant. We had always had problems with water getting in somehow, past the quadrants. I'd had 'em off, sealed them and then in desperation completely replaced them, but with only 'some' success.
I've now cured the leaks thanks to Stuart and Sheila, owners of Highlander, an ex Whitby lifeboat whose original name was The Robert and Mary Ellis. I believe that she was launched in 1909 and was a rowing boat.
When she was retired [I think in 1937] she went into private hands and was given an engine, and eventually a cabin and all the rest. She's still looking great.
Having a drink with Stuart and Sheila in the yacht club, Kath and I mentioned our frustration with the leaks. Sheila told us about their self same problem and invited us to their boat to see how they'd fixed it.
The following sounded a bit 'iffy' to me, but when I saw theirs I thought, why not...
It comes down to buying the thinnest lead flashing [about 1mm], the stuff you see on a house where the chimney meets the roof. It's very cheap and every builders merchant stocks it. Cut to a suitable width with a craft knife and a straight edge. Use a router with a 6mm bit and gouge a slot, in our case 40mm above the gunnels. Bend the lead, it's dead easy, to the shape shown in the jpeg. The idea is that the lead goes fully into the slot, down the vertical face and under the quadrant. Before placing the lead fill the slot and the area where the lead is going to sit with Sikoflex. With the lead in place, attach the quadrant in the normal way with stainless steel screws. It's important that the quadrant is fitted before the Sikoflex cures, so do the job by quadrant length.
It is important that you 'dry run' the lead, make sure it's shaped and fits. when you fit the quad and screw it down you'll find that the lead may move. Use a light hand, a block of flat wood and a small hammer to get the flushest fit you can, this is why the mastic should still be uncured.
We were limited by the router we used which is why the slot we cut was 40mm above the gunnel. The quad is 25mm high so the lead joint is above it. I needn't have worried, nobody even notices that it is there once finished. I can also say that this is the only application where mastic has actually worked for me on high humidity mahogany.
I'm sorry if I've made a dogs dinner of explaining this but I can assure you that this really does work. If you're unsure, knock a couple of bits of wood together and try it as a dry run.
Stu and Kath.
Our Cobb website
The jpeg is virus free. I drew it myself on autocad, a program I've used for 2 years without problem. I also ran it through my antivirus program to be certain.
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