I am currently refitting a 47 foot aluminium cruiser that was very cheap
because it was badly neglected by the previous owner. You can see details in my thread in the refit
The boat is very quiet even in rough seas due to being strongly welded, very stiff, and having blown in foam.
I have had to resolve a number of severe areas of corrosion / electrolysis, including holes in the hull, holes in the fuel tank
, plate thinning, corroded welds, and corrosion at the mast
base. I am in the process of grinding the paint, fairing, and corrosion off where there is deformation, then priming/fairing/sanding/priming/painting.
There is a lot of misunderstanding about aluminium boats on the internet
but resolving these issues has given me a good understanding of how and why corrosion and electrolysis occurs in an aluminium boat. It has also made me confident that any issue I find can be reasonably easily resolved by a grinder or welder.
1. aluminium oxide protects the metal. The corrosion in my boat has always been in areas of low oxygen, such as between metal plates, underneath damaged paint, under diesel
, or under wet wood or foam. Most if not all corrosion in my boat could have been avoided if the previous owner had fixed the deck leaks
and quickly addressed any paint deformation. If all areas of the boat are easily inspected you can quickly identify a problem (e.g corrosion under damaged paint) and fix it.
2. aluminium should not be in contact with most other metals. Some of the corrosion on my boat could have been avoided by welding on aluminium fittings instead of using stainless steel
screws and bolts to attach stainless steel
fittings. Isolating the metals will also help to avoid electrolysis.
If a steel, wood, or fibreglass boat had had a similar amount of neglect as my boat I think they would have much worse issues to resolve (rust, rot