For harsh and saline environment, the metal body type connector will only live for an year or two, unless special protective paints like ship-black are applied.
We always faced problems with Iron and copper open wire line in sea cost areas, disappearing due to salt corrosion. even though they never carry any DC potential. Power side also witches and bulb holders get metal corrosion and needed frequent replacements.
Perhaps, Anodized Aluminum might work, Teflon bodies may be better. Teflon based protective coated ans plastic versions might work
BTW, we may have to see the mechanical sturdiness of plastic shell connectors in hostile environments ( storms around sea coast and -ve temperatures in cold areas and too high temps of desert areas)