Access to keelbolts

S411 from 1979.

Now need to tighten keelbolts after grounding. Had one grounding few years back when going astern after first grounding ahead. So keel was slightly damaged at lower and aftmost point.  Had a new grounding this year.

See from drawing there are two bolts aft of the lifting eye. Assume they not accessible without lifting engine. Are they under the halfpipechannel from shafttube-area to sump?

Please Lars, your comment  would be most appreciated.

There isn`t any real leakage but before launching this year, some oily water was coming out from seam keel/polyester just 20 - 30 cm aft of draining plug.

Kind regards Thorbjorn, Ravn 411/036

Thorbjörn
There are two 20 mm bolts aft. The forward bolt is 320 mm aft of the aft lifting eye bolt, the other one 230 mm further aft. The forward bolt is close to the transverse floor aft of the lifting eye, and may be accessible through the lower part of the floor if the limber hole is big enough. For access to the aft bolt the engine has to be lifted. With the use of fiber optics you should be able to inspect the half pipe channel inside.
Tightening of the bolts is needed if there is a crack between the keel and hull when the boat is in the water, or hanging in slings. When using the lifting eye cracks are not showing in the same way.
Oily water coming out would indicate that the oil pan under the engine has been damaged, to be inspected when the engine is lifted.
Recommended torque for M20 bolts is 150 Nm.
Best regards
Lars

Lars, many thanks your reply which of great help.

Boat hauled 6 - 7 months every year but stll; can water ingress generally cause any problem with polyester over the years? Have planned to loosen all of the bolts and lift hull so that seam open to maybe a centimeter, inorder to replace sikaflex before tightening. But if it is normally adequate to just tighten the bolts, would be pleased to be advised. There is no real leakage. Understand well this can only be commented on in general terms.

Again many thanks.

Thorbjorn/Ravn 411/36

Thorbjörn
As your boat is out of the water that long every winter and has time to dry out, and your waters are cold, it is unlikely that problems will develop unless the barrier coat and gelcoat are completely gone in some areas.
It is assumed that your groundings have not been very hard. Unless there are cracks along the whole length each side the keel will not come off even if you open all bolts. The joint usually needs to be forced open, and it is not necessary to drop the keel unless the cracks are so big that bolts are visible, or rust is trickling out.
Can you get Sikaflex into the cracks with the boat hanging in slings? If not, it is recommended that the nuts and washers are removed in the cracked areas, and the mastic around the bolts dug out from the inside right down to the lead, and new mastic filled into the cavity from the bottom up to washer level with the yacht hanging in slings, i.e. cracks open. The yacht should stand on her keel when tightening the nuts. For M24 bolts the recommended torque is 260 Nm.
Best regards
Lars

Lars, many thanks your reply.

From your writing, it becomes clear that have to check seam and area around keel when hauling with slings and from there see how to proceed. Would be surprised to find cracks on water side. Inside there isn`t any visible cracks but need to check more. Groundings haven`t been that severe but over the years, have been through some, must admit. In the most likely case, joint is still solid in most of length. Understand it would be kind of wrong to force joint open unless it becomes obvious there is damage to it. Plan was to lift hull in slings with all of 10 nuts in highest possible position and let gap dry out a while. It certainly was good to learn this most likely becomes unnecessary by working with sikaflex and tightening.

Kind regards Thorbjorn/Ravn.

Thorbjorn, I have taken the lifting eye off as it just continually rusted. We keep it in the garge at home just in case! We did this by applying some heat to the eye to get the sikaflex to start to melt. Fairly easy job.

I have also removed the outer sheath between the keel stub and hull as this continualy cracked at the front, almost every year as the yacht rested on the ground. The fixing of this to the hull was always going to be a problem in trying to attach co -axile glass fibre layers to gelcoat. We now have the exposed joint so you can see if any leakage.  

Some years back I also removed the keel to check the bolts. Not a big job if done by a competant yard. It gave me the comfort of knowing the conditions of the keel bolts. We had to lift the engine to get at the last bolt as Lars has indicated.    

John, the job on your yacht is the one I first had in mind but after reading Lars`comments to this matter, it will hopefully be sufficient to tighten bolts only and not drop keel unless more than normal seam should appear in lengthy part of entire joint. Bolts should be okay since haven`t seen rust or rusty water in bilge or at bottom when hauled. Sort of looking forward to hauling this year to get a better view keel/hull area. This stage, have offcourse decided upon no more groundings... Thorbjorn