Marinisation (also marinization) is design, redesign, or testing of products for use in a marine environment. Most commonly, it refers to use and long-term survival in harsh, highly corrosive salt water conditions. 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.
There are three main factors that need to be considered for a product to be truly marinised.
- Resistance to corrosion
- Resistance to vibration
- Ability to function properly in conditions of constantly changing attitude (an object's orientation about its center of gravity)
Marinised metals include some of the following:
- Non-corrosive alloys that resist or are impervious to salt-water corrosion, e.g. 316 marine grade stainless steel; brass (an alloy of copper and zinc), or bronze (which contains copper with tin in place of zinc).
- The adjectival phrase "marine grade" being used when the above alloys have all impurities removed and are suitable for exposure to a marine environment.
- Metals electroplated or dipped in a corrosion-resistant material, e.g. galvanised steel
- Metals painted with special anti rust or anti corrosion coatings
- Plastic coated metals
Marinised electronics use one or more of the following protection methods. In most cases more than one method is used:
- Coating by a spray or dipping to protect from salt air and water
- Full encapsulation in some form of resin or gel
- Specialised mounting of internal parts for vibration protection
- Use of specialised corrosion resistant solder and corrosion resistant metals
Marinised batteries are usually gel batteries or sealed maintenance-free batteries. Not using marinised batteries in salt water can be deadly in an enclosed environment for many reasons:
- Sulfuric acid and salt water react to generate dangerous hydrogen chloride gas, necessitating the use of valve-regulated maintenance-free sealed batteries.
- The battery must have stronger plates and separators to withstand constant vibrations and impacts caused by large waves striking the hull. Plate collapse can cause short-circuits and electrical fires or explosions.
- A marine battery must function at any angle due to the changing attitude of the vessel it is mounted in. Gel VRLA batteries are best for this purpose.