Originally Posted by KD8NPB
All aluminum hull
boats will corrode severely if the powdercoating is not maintained, or if a copper based antifouling is applied. You can possibly mitigate it by drilling / grinding a spot down and riveting / screwing on a zinc anode.
Well... NO. Not really. You don't have to sail around very much in the world to see that there are an awful lot of aluminum boats with totally unpainted topsides. (It is usually a French thing!)
But there is a lot of BS thrown around here. There are many different alloys of Aluminum. Some are very well suited for salt
water exposure (5083, for example), others are not. The person who told you that marine grade Aluminum alloys contained zinc was blowing smoke out his ass. There ARE aluminum/zinc alloys but they are certainly not marine grade.
There are a LOT of reasons to buy or--to not buy--an Aluminum hulled RIB
. Thinking it is going to corrode out from under you is most certainly NOT one of them.
And recommending adding a zinc to an aluminum hulled dinghy just is silly. Zincs protect against galvanic corrosion between two dissimilar metals. I am pretty sure the dinghies we are talking about are ALL aluminum, so a zinc does nothing.
One last thought... The outboard
you are strapping to the back of that dinghy has almost ALL of it's submerged parts
made of Aluminum. It needs a zinc, because it has other metals too, but your aluminum dinghy will outlast your aluminum outboard