With correctly running under water machinery your (boat) vessel will last longer and run better. Their are no gas stations on the water, many breakdowns result from problems with these parts!
What is Underwater Machinery?
Underwater Machinery consists of propeller, struts, stern drive units, bushings, rudders and various other items necessary for the operation of a boat.
These always consist of metals that have corrosion resistance. Aluminum, stainless steel and bronze are extensively used.
Noble metals on the Galvanic Scale resist corrosion better that less noblemetals. Stainless steel will resist corrosion better that aluminum.
Underwater machinery must be inspected for collision damage and(corrosion) galvanic or stray current corrosion damage and wear.
The type of underwater machinery varies from sail and motor boats to jet skis as does the method of inspection.
Propellers are carefully machined, rotate hundreds of times per minute (RPM) and must be in good condition to give the best performance. Inboard boats have propellers attached to propeller shafts that (usually) rotate in a cutlass bearing set in a strut which consist of a bronze sleeve and a rubber lining.
Propellers are inspected for the correct size. The incorrect size propeller will impair the boats operation. An incorrectly size propeller can result in poor performance, transmission and engine damage.
Propellers must be free of nicks, wear and corrosion. Struts must be securely fastened to the hull and free of leakage at the point of fastening.
Underwater machinery must be properly grounded to the vessels grounding system. Cutlass bearings must hold the propeller shaft snug with out wear or end play.
The Aluminum casing of stern drive units must be free of corrosion, it must be without collision damage and must pressure test to 15 psi.
Aluminum casing are most susceptible to corrosion damage and must be protected by zinc. Stern drive units are essentially boat transmissions and exhaust systems that are submerged underwater.