Originally Posted by goearth
Any boat of any type MUST have anodes on if it is kept in the water for any length of time...
Presumably any metal boat, or boat with metal fittings/attachments? i.e. there's no reason to have an anode on a e.g. GRP/moulded hull, only on the engine, if it has one?
Regardless of anodes, I'm always personally slightly dubious about coatings on aluminium as well for marine use, especially on a hull living permanently in salt water. If a proper grade of aluminium is used in it's construction and welded in an appropriate environment, the aluminium should oxidise and self protect, and not need fancy coatings. Any minor chip or scratch instantly means the coating is breached, and unless fairly quickly (and properly) repaired, the damage will spread as water and air get in underneath it.
We run a big aluminium bluewater sailing yacht and a 16" aluminium dinghy as a harbour run around, and purposefully have as little coating and paint as possible! (we do have plenty of anodes as well though)