Replacing steel ballast

[Guest]

What can I replace the wet, very rusty steel scrap ballast with (all 2 tons of it I'm told), in the keel of my Colvic Watson motor sailer?
I'm considering doing this as part of drying out the entire keel area of the hull and then re-capping it from inside to stop bilge water, beer wine, blood etc. getting into it in the future and starting the process all over again.

OR is there something I can "pour" in, onto the rusty steel, to neutralise the rusting?

OR if I dry the rusty steel thoroughly (by blowing dehumidified compressed air through it for some days), do I really need to bother as long as it does'nt get wet again?

Any experience or suggestions please?
Malc Davis

 

[ccscott49]

The ballst could be treated with a standard rust killer, but you will need a lot of it=expensive. Epoxy pourted in would also seal it off. But if you intend sealing it off with a lid, I would pour old engine oil in after the top has been sealed to stop it rusting anymore.

 

[Guest]

Thanks for your suggestion BUT does oil do any harm, long term, to unprotected GRP?

 

[ccscott49]

It shouldn't harm the GRP, but it might be worth asking somebody, I have seen efluent tanks made of GRP and petrol tanks (motorbikes) So I would have thought oil would be ok. Sealing the stuff in there, could also be done with epoxy cement, I'm not sure of the name of this stuff, but its used extensively by the ferro cement crowd and it isn't expensive. It would also give you your new top to the keel, completely waterproof.

 

[rich]

have you thought about roofers pitch it will seal and be water proof,

rich )

 

[AndrewB]

I wouldn't attempt to treat in situ. Once you have rust in steel, it will continue to keep working underneath even if you seal it in with concrete, epoxy, 'De-rust' or whatever. I'm no chemist and don't understand why, but know its never any good painting over rust!

Oil is a good inhibitor, true, but I just hate the thought of having a permanent dirty pool of the stuff sloshing around in the bilge.

You could get the rust gritblasted off and then bed the steel, suitably primed, into concrete. Concrete is slightly pervious so the surface will need to be carefully sealed. Rich mentions bitumen (pitch) which is a traditional solution, but is not recommended if your bilge tends to collect standing water.