You can carry your HK out on the boat. The best product for anti-corrosion is Eezox. Do a web search and you should be able to find several real-life tests that have been done comparing it to about 5 or 6 of the most popular gun products. It really does a GREAT job in that application. Use it only on the metal parts. Don't slather it on the plastic, as it's not meant for that.