One simple step that is often overlooked when installing marine radios and other electronics, is the use of a waterproofing dielectric paste.
This compound, when used in mechanical connections like coaxial antenna ends used for VHF radios, will keep moisture from entering the connector and causing corrosion.
This material can be found in electronics supply stores or online. It is one of the many things that can be done to improve the longevity of electronics and radio installations in the harsh marine environment.
Capt Brett