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I took up the floorboards on my MK V for refinishing over the winter and this affords the opportunity to check the keelbolt torque.
There is no sign of any movement, and the keel/hull join is barely discernible from the outside as a very thin line. Is it worth bothering, or best leave well alone? If YES, does anyone know the torgue settings? The bolts are of different sizes so I guess they would have different settings? All advice welcome.
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Thanks - in other words "leave well alone"
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Not necessarily. Torquing if necessary, but not necessarily torquing, to paraphrase Mackenzie King.
Sail the boat for a season and see there is water coming in via the bolt holes, and after haulout, look for signs that the keel is moving significantly when sailing. If either is happening, check the torque settings. If not, be like the rest of us and immediately find something else to fret about.
David Weatherston
Towser, Toronto
C&C 27 Mk IV
David Weatherston
Towser, Toronto
C&C 27 Mk IV
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When in the water my long/skinny floorboard centre section requires a bit if effort to lift it, but with the boat now on the cradle that board is easy to lift. That would indicate that the upward force on the bottom of the keel has slightly changed the hull shape. If I were to apply more pressure on the pads to lift the hull a bit I suspect that would not be good for the hull shape??? Does that mean that the torquing of the keel bolts should only be done afloat?
Alan of SMOKE 1984 Mk V 002
Alan of SMOKE 1984 Mk V 002
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I am no expert, but I wonder if the tight fit in summer relates to wood slightly swelling in the humidity of summer, and shrinking slightly in the dryer cold winter air. If your Mk V is like mine, the sole is just 4 pieces of teak and holly veneered plywood. Personally, I would be surprised if you hull moves that much. I would think torquing keel bolts would be better when on the hard - the weight of the hull will be pressing down to lessen any "gap between hull and keel. Afloat the force will be opposite, and you will be pulling up the entire keel weight before any "gap" closing can occur. How much torque does that aspect alone require? For what its worth!
Barry. Oasis, 1987 Mk V
With regards to raising the pads to take weight off the keel: the conventional wisdom is DON'T. The boat is designed to rest primarily on its keel, and taking the weight on the pads will damage the hull, or at least distort it. On my last boat I would back the pads off until I could tell the pad was just starting to move, then tighten it up one turn.
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I had the engine out of Towser over one winter for a rebuild. As soon as she went back in the water, we almost hoisted the engine back in, to find that the engine beds had moved almost an inch in relation to one another. I assume that without the engine locking the beds into their relationship, and without the engine's weight, the hull was free to change shape fairly dramatically. We left her for a week with the engine in place but the mounting bolts loose, and at the end of it, everything was back where it was previously, including the cross-piece at the front of the engine box, which I'd not been able to secure previously.
We discussed torquing on shore and afloat some years back and my vote still lies with afloat, as the keel is free to make any adjustment in alignment required by the changed torque (though this should be very minor).
David Weatherston
Towser, Toronto
C&C 27 Mk IV
David Weatherston
Towser, Toronto
C&C 27 Mk IV
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Hi
there is no question - the MKVs hull deflects upwards when in the cradle. The middle section supported by the keel rises. If you unscrew the floorboards you can see that the aft end of the floorboards spring up to level - about 1/2" above the stringers.
I would not advise trying to tighten the pads - and it won't lift the boat that much anyway. You can do one of two things
1) worry
2) don't worry - there are 300 of these sailing around, and none, as far as I know, has broken in two.
Distant Thunder
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My experience is the same as Distant Thunder. My floorboards have lifted slightly upwards, and that is why the centre section is now relatively free. The change happened in an hour or so, from afloat prior to lifting, to sitting on the cradle. This I know as I was still winterizing and noticed the difference on going below when first ashore.
On the subject of torquing the keel bolts, it seems that the upward thrust on the bottom of the keel when the boat is in the cradle has the effect of pushing the full length of the keel bolts, with their washers amd nuts, upwards, thus reducing the normal downward pressure on the channels that connect them to the hull structure when the keel is hanging below the boat in the water. If this is correct, then the torque reading of the nuts should be lower when the boat is on the cradle, and only return to normal when afloat. Being very new to 'Smoke' I don't have the 'before' numbers, so any 'after' numbers would not help at this time.
Or am I all wrong?
Alan of SMOKE 1984 Mk V 002
Alan of SMOKE 1984 Mk V 002
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Last spring i retorque my keelbolts at about the specs on the black arts value. She was on is berth. I try to reach the 350lbs on the 1 inch bolt, but seem to me quite big so i stop to 300 lbs. All of the bolts were under ( somes a lot ) there nominal value. Work with the 40 inches long torque wrench handle is a quite hard. Better to be two people.
Each fall when i lift the boat, there was a crack on the joint of the keel, but not this time. I guess it is a good idea to check the torque because i don't think anybody do it since the last 24 years.
And yes the floor lift a bit when the boat are on his berth.
Jean of Neoga's MV
Jean, your experience with Neoga's keelbolts might support the theory that those readings will be lower with the boat on the cradle, and thus torquing should be done afloat.
Alan of SMOKE 1984 Mk V 002
Alan of SMOKE 1984 Mk V 002
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Bet the factory didn't float the boats to torque keel bolts.
Barry Oasis, 1987 Mk V
Our boats are elderly, but not yet ancient. Surely there is someone still alive and well who worked at the C&C plant and actually knows what they did with the new boats and their keelbolt torquing?
I've e-mailed South Shore Yachts on the subject, perhaps they have an answer.
Barry, you're probably correct!
Alan of SMOKE 1984 Mk V 002
Alan of SMOKE 1984 Mk V 002
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Barry, you are correct. I've discussed this matter with Ron Barr, who sailed "Smoke" for C&C when she was their 'showboat', and he confirmed that the keelbolts were torqued in the shop, not in water.
He also is a believer in the " if it ain't broke leave it alone" school of thought on this subject. So if there is no 'smile' then worry about something else.
Alan of SMOKE 1984 Mk V 002
Alan of SMOKE 1984 Mk V 002
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