bulbkeel bolts (nuts)

[Anonymous]

Dear owners.
I found a crack between the hull and lead bulbkeel.Dear owners.
I found a crack between the hull and lead bulbkeel.
Tell me how to tighten the the keel bolts at NC42?
What do I need to do?
Thank you and happy New year.

[Piers Covill]

Hi Sergey

Sorry I don’t have a NC42 but an NC43 which is a different boat. What I can do is share my experience on my NC43.

I spoke to Veli (veli.karja@nauticat.com) at Nauticat in Finland who sent me the plans for my boat which shows where the keel bolts are. Mine has about 18, which were all hidden: some under the false floor under the engine and prop shaft, and the others under the water tanks.

I had to remove the engine and water tanks and then cut away the floor all along the top of the keel. The problematic ones were right at the rear of the keel (I ended up cutting sideways into the keel above the nut to gain access), and one under the mast foot which is composed of iron punchings in resin and was seriously hard work to chisel away.

I undid all the nuts, suspended the boat in the lift and used a wiresaw to cut the lead keel away from the stub. Once on the ground, cleaned it up, and used Saba primer and sealant to refit (you need a lots of chaps to help with this to prevent the sealant curing before you can get it all back together…)

It was a worthwhile project as many of mine were leaking and some were loose (not even hand tight…) however my boat is 1984 so I suspect much older than yours….

Good luck..

Apologies if none of this is relevant, but hopefully helps.

Piers

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[39Schuss]

what would cause the keel bolts to need such a repair ? old age ? grounding ?

were the bolts crevice- corroded and did they need replacement ?

I the herd of lightly built US boats needing keel bolts periodically re tightened but did not know that this is required on nauticats.

[Piers Covill]

I think that in my case it was a combination of a 33 year old boat and (I suspect) some sort of grounding early on in it’s life. I have found evidence of a (bad) repair to internal non-structural bulkheads.

The tell tale for me was that when the boat was out of the water, the keel/hull join weeped water all winter…. Are you seeing this? Might be worth next time it is out of the water, rake out all the old sealant and monitor it. If there is no sign of water, it may be just that the sealant has cracked and got old. Clean up with acetone and seal as per below.

I wasn’t too surprised about needing to attend to keel bolts. It does happen in older boats regardless of design and make. In my case the bolts were fine, and I think what had happened is that some had slightly loosened (maybe as result of the impact) allowing some movement that had cracked the ageing sealant and allowed a weep of water in.

I couldn’t really see how to change the bolts (actually studs) anyway as they are embedded into the casting of the keel but there are enough of them and they were in good condition.

I glued the keel back on with:

qty 20 of 600ml sausages of Sabatack 750XL
1 litre of Primer 9102
2 litres Sabaclean 48

As well as making a flexible waterproof seal, it sticks like buggery and provides an enormous amount of additional strength to the mechanical join. You might want to consider this if you are re-caulking your join.

The worst bit of the job was getting at the keel nuts. I had to remove the engine, water tanks (which were rusted through due to the leak so had to be replaced anyway) and a bit of the internal bulkheads. The rear most bolt: it was easier to cut sideways into the keel to get to the nut, and the front one required removing the main mast and chiselling out a really hard mixture of iron punchings set into resin. It turned out that that was one of the ones that had been leaking – maybe as a result of impact on the forward end of the keel. Some of the nuts were only hand tight…

Best wishes

Piers

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