You will find the 5052H32 Aluminum performs well in the marine enviroment. The alloy exibits excelent resistance to corrosion and stress corrosion cracking. The only issue is water in the diesel fuel and condensation will sit in the bottom of the tank. The free water will lead to corrosion pitting. So, you will need to periodically clean out the tank or paint the inside. We use an Epoxy Polymide coating system.