Fin Keel, balllast & bolts

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Fin Keel, balllast & bolts

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keith
United Kingdom
118 Posts

Posted - 07/04/2012 : 19:43:57
I finally got round to having a go at the last of the big jobs on Sabreuse! Last year just before launch we noticed water leaking out the front of the keel to hull joint It was fixed temporarily with a band of sikaflex but by the time we hauled out in november she had started to leak a bit. I recently chopped of the grp covering the keelbolt nuts & they looked to be quite sound inside the boat. I could not undo them by hand so resorted to a large air wrench, this removed the nuts in minutes.
A substantial cradle was built to hold the ballast keel upright, it would not do for it to fall over!
The boat was jacked up to take the weight of the keel but it stayed well & truly attached to the boat.
I then made the discovery that Marcon did not bed the keel on rubber mastic as is standard, rather they had sat it on polyester filler & it had effectivly bonded the bolts to the hull.
I made a long hollow core drill up to cut the filler from round the bolts and much drilling later the keel relaxed its grip & slowly separated from the hull. Quite what condition i will find the bolts & keel bottom in when i jack the boat up i will shortly find out. More later!

keith
United Kingdom
118 Posts

Posted - 11/04/2012 : 00:32:32
Well the keel is off. Bolts look ok which is surprising considering their age & that they are not stainless steel.
The keel bottom is about 3/4" thick, not as thick as i thought, front bolt was leaking & there is evidence of delamination around the front bolts. I suspect she has had a good bounce on a sandbank.
Bit of a grinding & glassing job to put it right!
I think i will beef up the keel area a bit, there is plenty of spare bolt thread to add a bit more glass!
Still for a Forty year old boat that has spent 30 years in a Kent mud berth i suppose she has stood the test of time pretty well!

ianfr
United Kingdom
104 Posts

Posted - 11/04/2012 : 09:25:35
Keith

Good luck with this, don't forget to take lots of pictures for us all

Best wishes

Ian

Kind Regards

Ian

keith
United Kingdom
118 Posts

Posted - 14/04/2012 : 18:28:08
Today we have been cleaning the undersie of the keel stub up, not too bad condition, a big lump had come out next to the frd bolt & i found out why, when she was built someone had drilled the frd keelbolt hole in the wrong place. they had re drilled next to it and simply filled the redundant hole with P40.
The moral for boatbuilders is that no matter what you bodge one day someone is going to find it!
I have enough length on all the bolts to beef up the keel bottom by 6mm or so & think it worth doing this, also putting a steel strap floor bonded in across the end bolts to carry the loads up the hull a little. rather than a point load on a small washer.
I have some interesting photos!

looking4
United Kingdom
26 Posts

Posted - 14/04/2012 : 20:46:04
Hi Keith would be interested to see your keel photos and your steel strap mod

best wishes
Roger

keith
United Kingdom
118 Posts

Posted - 28/05/2012 : 09:02:39
Nearly there! did a lot of chipping & derusting on the iron keel, there was nothing wrong with the bolts only very minor surface rust that wirebrushed off leaving them good as new.
Last weekend i reinforced the keel stub area with CSM & vinylester resin this added 10mm to the thickness.
Also put a layer of 200gm glass cloth & epoxy on the bottom of the keel stub & wrapped up the sides by 25mm.
A keel like this needs to fit perfectly so the bolts were wrapped in masking tape then brown packing tape over that & all over the top of the iron keel, Yesterday i mixed a big wodge of epoxy filler & spread it over the ballast & lowered her back down onto it. The filler squeezed out & we left it to go off. Next job is to jack up a few inches peel the tape away, degrease & put in the mastic, before bolting up for good.
I have resisted the temptation to add modifications, an extra 10mm of glass in the keel stub represents nearly a 50% increase in thickness, its lasted 40 years already so i dont think it will need it.
I could drill & tap for another couple of bolts but in reality does it need it?

keith
United Kingdom
118 Posts

Posted - 12/08/2012 : 22:32:21
In the end i put one extra bolt in forward about 4" behind the front one. I had acquired a brand new long series 1" UNC tap out of a skip, tapping size is 7/8" and i drilled the hole in several size increments finishing it with an ancient black & decker gut buster drill at 375rpm.

Sabreuse had her first real test today with a long beat from Upnor out of the medway, got quite breezy, a splendid sail & she went to windward like a train.
Well pleased with her!
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