Loose keel

[Clyde_Wanderer]

Hi all, Lifted my boat onto its cradle yesterday, discovered the keel is a little loose, slight sideways movement, but she never took in any water around the keel nuts in the bilge while in in the water, infact she hasent taken in any water at all while on the mooring.
The keel is aprox 4"thick at the joint, 6ft long and about 3ft 6" high, and I would estimate somewhere from 750 to 1000 kg, I was told that the studs would be stainless steel, but I very much doubt that s/s would be used in a cast iron keel, can any of you good forumites cast a view on this and suggest the least costly and most secure remedy for me to carry out myself.
Would I be best to drop the keel down a few inches to inspect the condition of the studs, and reseal it? or just try tightening the nuts inside the hull and hope for the best?.
Thanks for any advice, Eamonn.

 

[steve6367]

To be sure you need to drop the keel and inspect - but do think about this carefully. I have just been down this road and it took 12 weeks and quite a lot of money to put everything straight. I am sure you may be lucky, but be prepared to open a can of worms!

The bolts on mine were mild steel - I believe they should be mild of galvanised on a cast iron keel...........

If you want anymore detail let me know.

Steve

 

[Mudplugger]

Eamon, We did this last winter on a mates boat, which had similar symptoms. If out of the water you should be able to lift the hull a couple of inches and wedge the keel up, then undo the keel bolts nuts.... this may need some effort!! and long bars on the socket....ease out the wedges to drop the keel and you should be able to see the state of the bolts! if they are shot then you will need to remove them (may mean lifting keel back up to get a 2nd nut & washer on the bolt, to undo it) and get your local blacksmiths/metal bashers to make up some new ones...,if not loads of sikaflex and lower the boat back onto the keel and after 24hrs take them back up tight. Sika should have given you a decent gasket by then. As a matter of interest my '79 Discus had a cast keel with s/s keel bolts & nuts... HTH.

 

[Plomong]

If you drop the keel, be sure to inspect the laminate around the bolt holes. If there is any sign of water absorption or laminate distortion, more work will be needed to set things right. The keel could be loose because the area of fibreglaas that should keep it rigid is not now capable of doing just that!!

Hope it is not that serious.

 

[Clyde_Wanderer]

Hi Steve.
Thanks for your reply.
I have tried emailing you, but it keeps failing.
Can you go more in dept to the hassles you had with your keel, so I can give a bit more educated forethought to my plan of action for the keel repair.
Do appreciate your help.
Thanks, Eamonn
Hi Plomong, thanks for the advice, incidently, what is the remedy if the grp around the holes is showing signs of moist ingress, would a reamout and some sort of sleeve with a flange be a sufficent answer?

 

[Plomong]

Any damaged area would need to be removed and rebuilt -- a tricky business, but doable in fibreglass.

I do hope that is not part of your problem.

 

[oldsaltoz]

G'day CLYDE_WANDERER,

Your first step should be to check the bolts, if one or more is broken it should come away pretty easily, you might be lucky and be able to replace it / them without removing the keel.

The last keel repair I did was a mongrel, the first thing is to secure the keel so that it can not move at all, including a brace to prevent it lifting at one end or the other.
We used scrap steel and welded bars between the keel and the cradle, looked messy but worked really well.

Removing the bolts took some effort, stainless steel into cast iron. then the slow process of lifting the boat clear of the keel to get a look at what had gone wrong. We used a jack at the bow with a block shaped to fit the hull profile with a layer of carpet on top and a recess in the bottom so the jack could not slip out, a second frame just behind the jack was stacked with timbers and wedges on top, the wedges were kept tight at all times, then another timber slid in when the wedge ran out of lift.

The stern was on a sling (Fixed Fin Keel and rudder skeg) so a chain pull on each side with a second chain inside a poly pipe with a fire hose over that was used as a safety back up, shortened one link at a time.

We got her high enough to get a look inside and discovered one of the stringers had a broken back and a crack dad opened up behind it in the hull. This meant parting the hull and keel with a crane and setting the hull down on timbers with enough space to work on the underside of the hull.

Repairing the crack in the fibreglass was a straight forward task. Finding a suitable timber was another story, I was all for replacing the timber with glass, but the owner insisted the timber be replaced. I about to start laminating one when we located a suitable lump of spotted gum. Needless to say it was weeks between lifting the boat from the keel in it's cradle to getting her ready to drop back into the water. The only modification was larger spreader bars under the keel bolts that we extended to rest on the stringers, this made the structure stiffer around the keel and would also provide an early warning in the future should anything move.

She is still afloat and has had no further problems. but I can assure you it was no picnic.

Good luck. Andavagoodweekend......

 

[Clyde_Wanderer]

Thanks old Saltoz.
Sounded like quite a big undertaking, But I am sure there is no timber or stringers as such in my boat, it looks as if the hull is totally grp.
The bilge in the centre of the hull is only about 5-6" deep, and I would estimate that the hull thickness at the keel mating surface is somewhere between 3-6" and Iwould say solid grp laminate, there is about 6 studs which are about 1" dia, with big nuts and Ithink plywood backing pads under the nuts.
My fear it that if I go ahead and tighten the nuts without checking the condition of the studs, and one or more studs break in the process, that in might break even with the top surface of the keel or even below, then I would be in the sh...t
I will try to take some pics of the setup the next time I am down, and put them on the forum or email them to you, if you email me your add.
Thanks again for your advice.
I must admit I am really worried that the hull would be wasted, as suggested could be a posibality by yard owner.

 

[oldsaltoz]

G'day again,

Don't tighten the keel bolts, take note of the nut position and try to loosen it 2 turns, then return it to it's original position and repeat on the next bolt. This should give a clear indication if a bolt (actually a stud in most cases) is broken, by doing them one at a time you will not be increasing the load on the remaining bolts. Avoid removing a bolt completely as anything loose or liquid will fill the hole and prevent you getting the correct torque when tightening.

If none are broken then I would be removing the ply backing plates, (one at a time) ply in a bilge is not a good idea at all, consider replacing it with stainless steel and eliminate the soft ply.

I hope this helps, good luck

Andavagoodweekend......

 

[Clyde_Wanderer]

Thanks again old soltoz.
Thing is I dont know what torque the nuts should be, or dont know where I could find that out.
How do you suggest I will know if they are tight enough?
Also how will I know if the keel is still moving or not, with the boat sitting on the cradle and the keel on the blocks of timber under it?
Sorry about all the questions.
Thank, Eamonn.

 

[Swagman]

Just some trivial input in case you do have to drop the keel.

When we had a keel added to a GRP yacht, the designer (Swarbrick) and boat builder we engaged to basically put the keel on, first ensured the hull was mounted high in a cradle, lined up studs to drill hull holes, ensured all mating surfaces were as parallel as possible, and then after copious bog offered up the keel to the hull.

Note that it was keel pulled up by studs / bolts onto the hull - as opposed to the hull lowered onto the keel.

Then 48 hours for bog to fix, nip the bolts tight using aforesaid torque bar - then fair off / antifoul / into the water.

This method seemed a lot of fuss and nonsense to me at the time as it seemed to take forever to get it right - but they insisted it was the 'only proper' way.

Their argument was this method set the bonding up in the way it has to function for most of its life. ie when in the water the hull does not rest on the keel - but the keel most certainly does hang off the hull!

Have to say it never ever moved (no - not even that little thin trace of exidation at the join) but can't swear that's only because of how they did this joint.

Good luck
JOHN

 

[Heckler]

As an old mechanic said to me once TAYFC, tight as you f can. when i was a lad working down the pit we used to have to extend the panzer (a chain conveyor belt) the links were held together by 5/8" bolts. as a game to test our teenage strength the old fitters would bet on whether we could bust the bolts with a pair of ring spanners by tightening them, the spanners were about 18" long. no chance. so if your bolts are about 1" thick you aint going to bust em!!
Stu

 

[Clyde_Wanderer]

Thanks everyone again for all the advice, and I like the TAYFC bit, My boss made us lift two of the old 56lb weights above our heads first thing every morning, one in each hand, its no wonder I have arthurtherites in all my joints now, and I am only 45.