I live on the water as well and have been splish-splashing around in, on or near salt water for most of my adult life. My guins, knives and gear need attention and still show some seasoning from being in and around this environment. Here's what Ive found over the years:
WD-40, Great for dispursing water after a fresh water cleaning. It can be sprayed on just about everything but evoparates and therefore isn't the best for long term storage.
Mineral Oil, I use it on all of my knives, especially the ones that will be in contact with food, or at least food that
I will be eating.
Motor oil, Great, great stuff for protection in and around water and salt water. It is oil and has additives that fight corrosion and other harmful to metal
stuff.
Militec, Very good firearm and folder lubricant, I guess it also has protecting qualities but have cheaper stuff for widespread (pun intended) protection.
RIG, A gunsmith supply grease that is great for long term protection and application to areas that have already started to get aaway from you.
YMMV.
CLP, What gun fancier doesn't keep this stuff at the ready in every corner of the garage, house, gun room and tool box. Good for cleaning and lubricating but, like Militec, I have my Mineral Oil and Motor Oil for coatings.