Posted: Wed Jun 02, 2010 8:53am

The water from the engine bilge on my cruise style narrowboat has finally dried up and I see the state of the bottom. I am shocked to discover that the paint has lifted and it is very rusty down there. The bilge contains heavy ballast and is an awkward shape and hard to access. What can I do?

Posted: Wed Jun 02, 2010 11:02am

Depending upon the age of the boat and hull builder the bottom plate could be anything between 3mm and 10mm in thickness. If you fit the "typical" demographic for canal boat owners and the bottom plate is 10mm I suspect any worry about the rust will turn out to be academic because it will not be your problem when wet things happen. In this case I would vacuum as much of the dust etc away from the ballast and give it a liberal soaking in something like Vactan or Fertan and when that is dry a liberal dose of something like really hot Waxol which I hope will creep under the ballast and solidify to an extent. If you have an older boat with a thinner bottom plate or are younger then I am afraid you need to get all the ballast out. Rotary wire brush (for goodness sake use a dust mask) all the rusty areas then run over them with a angle grinder to roughen the surface. You will still have rusty pits so treat the surface with Vactan or Fertan and when it has cured a coat or two of anti-rust primer followed by several coats of bilge paint (I use Hemple but other makes will be just as good). Alternatively give it a couple of coats of blacking over the first treatment. In my view it is very bad practise to put ballast on the baseplate of a cruiser stern. See if you can accommodate it on the uxter (swim) plate. Wherever it has to go it would be a good idea to stand it on something like floor tile distance pieces (larger plastic cross things)so air can get underneath it to dry out any condensation. I try to clean and paint my engine room bilge every year but usually find it gets done every second year. The final option is to pay someone you trust to sort it out.