Aluminum repair more expensive than steel on vehicles

Aluminum and steel in a marine enviroment (salt water) is a no brainer ,the solutions are many and no mystery.The dutch have been building steel hulled aluminum superstructures since the 60's and the U.S. navy also .
Galvanic corrosion is easily dealt with(active and passive) , just plain aluminum oxidizes to a incredibily tough surface that protects the metal under neath,compare to steel ,it will oxidize continuously until all the iron is gone.