Tightened my keel bolts today

30boat

30boat

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Since the boat is 28 years old I thought it would be a good idea to check the keelbolts tightness.Using an an old 22mm prop shaft for a handle through a water pipe connected to the socket it wasn't too difficult.What astonished me is how loose they were.My advice to everybody is: check your bolts if you don't know when they were last tightened.
 
As Mike says, you could be doing more damage than good.
It would be advisable to drop keel, or pull studs to check their condition before horsing up nuts especially after 28 yrs.
The fact that the nuts were quite loose could be indicative of stretchy studs/bolts.
Dont mean to alarm you, and hope I am wrong in your case.
 
Thanks for your concern .Maybe I wasn't very clear.The nuts were still tight but not as much as I would have expected. On my boat there is no sign of keel movement or even leakage.It is natural that after a few good years the nuts need to be retightened especially if they weren't done up shortly after commission .There are many thousands of boats of this age and type of construction that never had their bolts checked or retightened and sail happily on.I didn't apply enough force to stretch the bolts anyway,I'd never be able to do that given the massive size of the bollts.The fact that the nuts were not too tight only means that as the hull works in a seaway over the years things settle andt even fiberglass can compress so that has to be corrected.On my previous boat I also retightened the bolts and the nuts were also in need of a retorque.
 
Hi 30boat,

Yes, I agree with you, I doubt very much if you could stretch the keel bolts on a Fulmar without truly vicious leverage as they really are massive, although IIRC, the end ones are only 20mm(?) so perhaps a little care here.

I think you make a good point - most people, myself included - tend to leave 'fings wot ain't broke' well alone which, in the case of keel bolts, means if they're not leaking, leave them!

Glassfibre can and does 'crush', so if it makes sense to tighten a cast iron engine head down after a period, it must make sense to at least check something as relatively soft as GF from time to time.

Doh, you've made me think about it now, so I think I'll have to check mine next lay-up!! /forums/images/graemlins/frown.gif
 
I am amazed that after 28 years the nuts actually turn without twisting the bolts or causing them to rotate in their holes (you of course checked that that is not the case,by painting a white line across the end face of the thread)..
By the way I had an inexpensive American boat (Pearson) that had a bolt-on keel attached with a series of short through bolts around the flange rather than along the centre line..easiest removal and replacement I have ever done,as they were only 100 mm each.
 
I hope that you just tightened them, rather than stretch them past the point of no return.

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No chance of stretching the bolts...What I have seen is the nuts being driven through the fibre glass by the use of excessive torque. On a Westerly Vulcan they were driven over 25% through by crushing the fibre glass....do not torque up keel blots on a fibre glass bolt as if you are torquing up cylinger head bolts..:) Can do more harm than good!!!
 
The bolts would have rotated in their holes only if the threads were corroded or weakened.In that case the spanner wouldn't have come to a very definite halt as it did but would have given off a spongy feel.The bottom on my boat collects only dust and when she is lifted there is absolutely no movement anywhere around the keel joint,or any other signs of movement like rust streaks.
 
Hi Jerryat

There I go again worrying you.I don't think you should be concerned about your keelbolts.As I said most people don't bother and their keels stay in place.On my boat only the aft bolt is 20mm and I didn't do it as I didn't have the right size spanner with me.I'll do it later with a regular handle,so no danger of overtightening.
 
Yes I agree.That would be bad,but it would take some doing on a boat like mine.There was no sinking of the washer plates.

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It happened on a boat just like yours and was not difficult to do!!!!!!!! Cost £5000 to rebuild both keel pods and restore hull thickness in way of the keel bolts.

The correct torque depends on several factors but will not be such high a figure as when tightening the same sized bolts on something like steel. There should certainly be no attempt to tighten up to just below yield of the bolt as the fibre glass will crush first .
 
I couldn't resist commenting on the twisting thing. If the bolt is in poor condition, it might not be the whole bolt turning; it might be the bolt twisting! You'll see the top of the second bolt from the right and the twist marks. This was with an torque wrench size bar on the socket - so not a lot of ummff. And that was undoing it! Marking is essential to know what exactly is going on!

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[ QUOTE ]
Hi Jerryat

There I go again worrying you.I don't think you should be concerned about your keelbolts.As I said most people don't bother and their keels stay in place.On my boat only the aft bolt is 20mm and I didn't do it as I didn't have the right size spanner with me.I'll do it later with a regular handle,so no danger of overtightening.

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Good grief, I'm not worried in the slightest!! I have a good look at my keelbolts/nuts each lay-up, and a close look along the hull/keel joint at the same time. Not seen anything remotely like a problem, but if I do, I might just check one of the keel bolts next winter, to see if there is any looseness.
 
I have a UFO 31 and some years ago I enquired of Holman and Pye what the torque should be on the keel bolts and they said 120ft/lbs which is quite a lot. Having said that the bolts are very large with quite a coarse thread pitch.

Ted
 
I am just a little concerned at how you actually set about tightening them, without any means of checking the actual torque applied.

You said you used a prop shaft ..... how long? The torque wrench in my tool kit is under 500mm long, and can quite easily generate a force of up to 180 ft/lbs. Ok that needs two hands, but most keel bolts should be about half that - which I can do swinging the wrench with one hand.

A shaft 2 or 3 feet long is capable of developing several hundred foot pounds torques without too much effort from the operator. Not only enough to stretch and shear quite hefty bolts but enought to damage threads and to cause stainless bolts like those fitted to most Westerlies to gall and seize irretrievably.

A reasonably accurate click stop wrench only costs £20 - £30, and one that works by measuring the degree its handle bends against a scale, costs half that. Well worth getting one considering the trouble and damage overtightened keel bolts can cause!
 
I have one that I use for engine work.I used an old shaft in a t bar configuration,nothing like 3ft long.I remember a picture depicting keelbolts being tightened in just that way .As I said before it would take some doing to overtighten those massive bolts with the setup I used.
 
Thats Ok then /forums/images/graemlins/smile.gif I had visions of you putting all your weight on 3 - 4 foot of prop shaft - in which case you would have found them turning quite a long way. You then described how they came to a definite stop - which is of course what would happen when seriously overtightened s/s bolts gall their threads and the nut locks up irretrievably! I beleive that could happen around 350f/lbs torque on Fulmar size bolts - a figure easily acheivable with a long enough bar! That is assuming the moulding survives the pressure.
 
The crushing doesn't happen instantly it just gradually happens
I believe the method used at the factory was to harden up the nuts and then a bit for good luck! certainly never saw torque wrenches being used!
There has been discussions on the Westerly web site re keel bolt tension, might be worth a search
 
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