Lowering a full length keel?

[jamie N]

I've a keel bolt 'issue' on my carvel Folkboat, where a bolt was looser than it should've been, and has induced a leak which requires the sealing area between the hull and the keel to be 'redone', requiring the keel to be lowered/boat to be raised.
The distance needed for this is around about 6"/15cms.
This might take some time doing the necessary repairs, so I'll not be able to have it hanging in the slings at the marina, thus the boat's coming home on my trailer, which is why I'm looking for advice from those who've maybe done this before.
My 'loose' idea is to get 8 'acrowprops' and position these so that they're supporting the hull in an appropriate fashion, release the keel bolts and then lower the trailer by deflating the tyres, which should give me enough space, and be very quickly reversible.
The hull is 2000kgs and the keel 1000kgs, so the acrowprops are supporting a nominal 250kgs each.
I'll have to fabricate 'prop-pads' to spread the weight over the maximum area possible, which won't be a showstopper, but can't see too many other negatives, and invite comment.

 

[Refueler]

Just a thought ...

I would be cautious about using Acro's especially that the keel will probably require persuasion to 'break joint' ...... while trailer is supporting hull - you're fine ... but once you lower that trailer - you are relying on vertical acro's ????

I would much prefer to transfer from slings to a proper yard cradle with extra pads / supports holding the hull higher - keel of bed / ground. That way you can move about the boat safely etc.
A couple of trolley jacks under keel when you drop it .... don't wait till job done - you wont get them under to jack keel back up !!!

 

[ProDave]

Deflating tyres to lower the trailer might work with tubed tyres, but likely to end badly with tubeless tyres.

 

[debenriver]

I think that to drop the keel you will likely need to drive all the keel bolts. So you will need enough clearance for this – or be able to dig holes in the ground (less good because you will have difficulty driving the keel bolts back up).

And - yes - build a proper cradle. Using Acrowprops is not very safe. You likely need to do quite a bit of 'persuasion' driving the bolts out and getting the keel to drop.

Cheers -- George

 

[penfold]

I think that to drop the keel you will likely need to drive all the keel bolts. So you will need enough clearance for this – or be able to dig holes in the ground (less good because you will have difficulty driving the keel bolts back up).

And - yes - build a proper cradle. Using Acrowprops is not very safe. You likely need to do quite a bit of 'persuasion' driving the bolts out and getting the keel to drop.

Cheers -- George

I'd agree, the few ballast keel removals I've been involved with the hull/keel joint has put up a fight, if the bolts hadn't been withdrawn it would have been impossible. The acros propping the hull need braced at least to the acro opposite, once you've done that you might as well make it an actual cradle. The keel needs a cradle too, a tonne of cast iron wobbling around unrestrained is an accident waiting to happen.

 

[William_H]

I would suggest rather than deflate tires, That you jack up the trailer under the axles by 6inches then support the hull then remove the jacks under axles.
re supporting the hull. You might consider a cross beam under the stern area set up on stands. Drums or similar. With blocks and jacks to get height right. Do similar with area in front of keel.
Just as a thought can you not remove the loose bolt and fill the hole with sealant hoping when bolt goes backn in it will pump sealant out in to void. ol'will (the eternal bodger)

 

[Refueler]

Seems that my comment about Acro's is supported by others .... not a good idea.

Lets look at this ... and what do people do when they want to put boat on / off trailers ... and how the transport guys do it without 'Hiab' crane ...

Strong beams and jacks with multiple blocks.

Basically a beam across ahead of keel .... other beam across behind keel. Sand bags or other wedges on beam to steady hull ... jack up each beam - blocks under. Jacking done in stages to avoid to steep a pitch angle during op.

Once at height - plenty blocks and wedges to steady whole affair.

I know this is a lot smaller boat - but principle is the same :

No Acro's used ...

The FB is a classic lovely boat ... please be careful and look after her .....

 

[jamie N]

Thanks for the replies. Unfortunately the shape of the Folkboat renders it impossible to support the hull athwartships aft of the keel, and very unsafe ahead of the keel. The boat must be supported from the sides, below the waterline, where the hull shape is most suitable. To support the bow will require a prop from each side due to the trailer.
The Acrowprops for hire are basically of the boat stand type, not the building site 'vertical only' variety, so I don't envisage this being an insurmountable problem.



The keel bolts screw into the keel, and will be loosened to allow vertical movement of the keel downwards. I think it unlikely that defective keel sealant alone will support 1000kgs of keel as it's released, however the bolts won't be fully removed, they'll be loosened to allow enough movement down. The contingency here is that if the bolts aren't long enough, I do have 'bar' that's long enough to prevent the keel 'falling over' by using it as a podger.
The boat won't be raised more than 15cms, and that's only if the keel does release, otherwise it'll be raised only so far as to allow the work to be done to release the keel.
The difficulties some have had in getting the keel to release are welcomed; I'd not really thought that'd be an issue, given that's it's the reason that I'm having to work on it, which is quite ironic really, so I'm glad that it's been pointed out!

 

[Refueler]

Yes sorry .... I know the FB has a long keel ... but as FB's come in a number of variants - I see you have the original full version ...

Keel Bolts .... it does not take long for them to 'seize' in their guides and need serious whack to 'drop' them ... Remember - you are not only 'breaking' the bolts seal .. but also the years of that keel joint itself.

 

[VicS]

Thanks for the replies. Unfortunately the shape of the Folkboat renders it impossible to support the hull athwartships aft of the keel, and very unsafe ahead of the keel. The boat must be supported from the sides, below the waterline, where the hull shape is most suitable. To support the bow will require a prop from each side due to the trailer.
The Acrowprops for hire are basically of the boat stand type, not the building site 'vertical only' variety, so I don't envisage this being an insurmountable problem.

This type of thing... maybe but ordinary props would not be stable.

 

[jamie N]

It doesn't take long for a plan to fall apart does it!
The trailer for the boat has been judged 'beyond economic repair' with a hidden (to me) fault.
Ho hum, plan B will be less cost effective but workable.
Cheers for the inputs.

 

[Freebee]

when I was in africa we had to position a heavy machine in a factory, we lowered it onto bags of sugar and then washed the bags and contents away with a high pressure hose, leaving the machine sitting nicely on the floor , that sort of method may get your keel on the floor but does not help with getting it back up sadly.