Need advice on how to replace Hull to Keel Joint

gonesailing

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I have a 1/4 ton GRP boat circa 1978.
Notice that the keel bolt heads are a little rusty and that the keel/hull joint is letting in water. For safty I must break the joint itself by getting the boatyard to lift my boat off its keel so that I can clean the keel flange and rebed.
Has anyone done this themselves and if so what tools, sealent and preparation do you advise.
I am worried that the bolt will not release or even worse break? Once removed I want to replace them, but with what type of bolts?
Advice + encouragement please
 
G

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can be quite easy or hard, depends on the type of boat / keel / cradle and tools available.

take off one nut -take it to your local steel stockist (probably 3/4 inch) stud bar and nuts should be readily available at reasonable price.

did my keel bolts on Ruffian 23, in cradle with adjustabe support pads and hydraulic jack without need of crane took less than a day on mu own.
if similar e-mail back and maybe I can give you the method I used and advice of potential problems.

peter.ashurst@vships.com
 

jfkal

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Can be tricky indeed. Get also a set of bolts one size up. I case they break and you have to drill them out.
Use Sikaflex AND clean surfaces thoroughly AND use the right primer. There are different primers for GRP and iron etc.
 

davidwf

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Looked into doing this last year, make sure you get a proper support for the keel most boatyards have a modified cradle that have adustable pads to hold the keel upright once released. Also you really need to sand blast the top surface to get it clean before priming it.

I concludd that the jobs best left to the boat yard who will be charging you for lift on and off the keel so the work required in between is relatively cheap compared to the hoist hire.
 

Strathglass

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I did this several years ago on a 25 ft wooden day boat with a cast iron keel. Just braced the hull well on a trailer, made a cradle for the keel (weighed about a ton ) then took the nuts off and tried to get the bolts out. Took about two days, three of them were rather rusty and had to be drilled out.
moved the trailor and keelless boat out of the way to gove access to the keel.
The original were Iron. I replaced them with custom made bolts.
To reassemble I just moved trailer + boat back over the keel.
Iain
 

gonesailing

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Many thanks for all the feedback.
Will investigate the cost of boatyard doing all the work, however, as I am on a budget, I guess I will have to undertake the work myself and let the boatyard lift the boat on/and off the keel.

Keelbolts are in fact bolts tapping down into cast iron keel. So guess I need to extract and replace one bolt at a time prior to getting the boatyard to lift the boat. What sort of tools/ wrenches and gismos will I need to actually get the bolts turning?
 
G

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Seen this done recently on a slightly larger boat, needed to remove rig to prevent hull from falling over once keel was removed, then crane hired to lift hull and keel into special keel cradle where keel was secured using wedges, go on board and remove bolts. Crane driver lifts the hull off keel, but was stuck very well with sikaflex and didn't want to come off, steel wedges driven between hull and keel, eventually hull lifted off keel and placed into another cradle. Crane comes back a week later to repeat process in reverse.
 
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