One type of cathodic protection system is the sacrificial anode. The anode is made from a metal alloy with a more "active" voltage (more negative electrochemical potential) than the metal of the structure it is protecting (the cathode).

Magnetic compass is an instrument uses a magnetic needle pointing to magnetic interaction energy in the Earth's magnetic north point (south) pole of principle made.

Anchor type: marine stockless anchor, high holding power anchor, offshore anchor, marine stock anchor, yacht anchor, boat anchor etc. Anchor includes anchor head or crown, crown Pin or Stock, Fluke, Shank and Anchor Shackle.

Marine valve is widely used in marine pipe system. According to the medium, the temperature, the material can be cast iron, cast steel, bronze, brass, stainless steel… etc.

Life rafts come in many shapes and sizes with virtually no standardisation between manufacturers. Square, oval, hexagonal, octagonal, single buoyancy tube, two stacked tubes are just some of the choices. Cost, weight, intended purpose and people-carrying capacity are usually the determining factors.