Adding ballast

[clonlara]

Hi all, just lifted my boat out for the winter with the idea of doing some work to the lifting keel over the winter. original plan was to drop the keel clean it up and get it galvanised, possibly adding some weight to the foot as the boat (Gibsea 76) can be quite tippy. On investigation it seems that the keel stub is actually hollow at least it sounds hollow when tapped with a hammer. So would it be possible do you think to drill a series of holes in the stub and pour in some molten lead and what sort of a difference could I expect.
Colin

 

[vyv_cox]

Manufacturing a hollow keel stub sounds like quite a challenge. Are you sure it's hollow? I would try some experiments with bags of sand to see whether it's worthwhile doing anything before trying drastic experiments.

 

[KenMcCulloch]

So would it be possible do you think to drill a series of holes in the stub and pour in some molten lead and what sort of a difference could I expect.
Colin

I suggest a simple experiment. Take some scrap GRP, preferably a concave shape, you are bound to be able to gind something lying around. Melt a kilo or so of lead and pour it into the concave grp and observe the effect. I am not exactly sure what will happen when you do this but I am pretty sure it would not improve your boat in any way.

 

[CreakyDecks]

Don't pour molten lead into anything unless you can be absolutely sure it is bone dry.

 

[William_H]

I suggest a simple experiment. Take some scrap GRP, preferably a concave shape, you are bound to be able to gind something lying around. Melt a kilo or so of lead and pour it into the concave grp and observe the effect. I am not exactly sure what will happen when you do this but I am pretty sure it would not improve your boat in any way.

Answer is that polyester resin will burn and smoke to an extent that would effectively destroy the fibreglass.

However I made an extension to my lifting f/g keel by molding a f/g piece around the tip of the keel. I removed this mold and mounted it about 4 cms proud of the keel tip. (keel upside down). I filled the cavity with molten lead. (About 15kg) there was a lot of smoke and the mold was effectively destroyed however the f/g of the keel seemed to survive although probably damaged it was now covered in lead. I then covered the new lead with fibreglass to make the keel complete. The extended keel has survived now another 20 years or more.

I would suggest the OP drills into the stub keel first to confirm it is hollow. Then make up a mold to cast lead externally into plugs or similar if it is indeed hollow. I understood usually the stub keel is filled with lead. Ultimately though additional lead under the floor is nearly as good and is easily removed if it proves to be not a good idea. good luck olewill

 

[Grajan]

Fibreglass burns very readily! I wouldnt go there if I were you. I have successfully used lead shot in small void spaces and in larger areas encapsulated it with resin although this has to be introduced very slowly otherwise the exotherm build up will damage the hull

 

[nimbusgb]

Buy lead shot and pour it in to a hole. Not cheap but safe as houses. Follow that with enough epoxy resin to keep it all together. job done.

 

[Poignard]

If I were you, I would ask the advice of the yacht's designer before doing this.

Extra weight low down can make the boat's motion violent as well as imposing additional strains on the keel mounting.