What Caused the 930′ fuel tanks to corrode out? And how to fix!

You need to check the bonding on your Voyager Catamaran, In the past it was done incorrectly, and Derek did not address the issue, lets hope they read this and fix it!

Bonding simply means wiring all the boats metals together. This is done because of the galvanism caused by the different metals. By wiring them together, the differing potentials are equalised. Bonding does not solve problems of electrolysis, but it does spread the the flow of current around over more metal, so that 1/4 volt or so won’t cause any damage. Whereas if that 1/4 volt were going to one small seacock or the fuel inlet in the voyager cases, it would eat it up in a hurry. In other words, bonding lessens the effect of small amounts of current. On the other hand, it also spreads it around to all underwater metals.

Bonding systems use wire and ordinary crimped ring terminals. After a while these get wet and corroded. Electricity doesn’t flow very well through corroded metal, so your bonding system after a while stops working. To maintain it, simply cut off the old terminals and install new ones. You must also take a close look at the hose clamps used to secure the fuel lines onto the tanks in your Voyager, as these where generally different materials, Stainless against a aluminium tank, They should be bonded also to prevent failure and flooding the engine room with fuel. (As you can imagine this is more dangerous on the 930 as most where petrol not diesel.

If your unsure if your vessel is bonded probably, please get a qualified electrician preferably with marine experience to inspect your vessel.

Electrolysis is stray current escaping from the system and is most damaging. It is an abnormal condition on most vessels. When this happens, it will eat up the zincs in no time, usually leaving that metal looking bright and shiny. Therefore: Shiny zincs = electrolysis.

You can test yourself if you have a multimeter, you should not have a voltage reading over 1/4 of a volt if you do, seek immediate help to fix the problem.

Thank you to all the people that emailed requesting further information, I will update this as much as possible.