[1] Most commonly, it refers to use and long-term survival in harsh, highly corrosive salt water conditions.
[2] Marinisation is done by many manufacturing industries worldwide including many military organisations, especially navies.
In some instances, cost is not a guiding force, and items may be designed from scratch with entirely non-corrosive components engineered and assembled to resist the effects of vibration and constantly changing attitude.
In others, particularly in "marinising" an existing product that was not designed specifically for a marine environment for sale in the public marketplace, a balance must be found between the competing criteria.
Not using marinised batteries in salt water can be deadly in an enclosed environment for many reasons: This naval article is a stub.