If the stern drives of the boat has got damaged due to prolonged use and galvanic corrosion, and you are thinking for a long time of a repair, then it is the right time to go for replacement stern-drives. Replacement stern-drives are available in a variety of range and they can be OEM replacement stern-drives or MerCruiser original stern-drives. Different manufacturers have stern-drives of different features, but in general all of them also manufacture hydraulic replacement parts compatible with MerCruiser stern-drives. Such parts include hydraulic pumps, trim cylinders, hoses, fittings, pipes etc. Replacement stern-drives usually come with a warranty period specification from the manufacturers. Warranty periods are generally three-year fault free warranty. The pricing of replacement stern-drives can range from 700.00$ to a couple thousand dollars.

Stern-drives are marine propulsion units that contain an engine and a drive unit. The engine is placed inboard the boat, just forward of the transom or the stern (hence the name stern-drive). The engine delivers the power via a shaft, running through the transom and powers the drive unit. The drive unit is located outside the hull. The drive unit holds the gearing system of the unit and also the propeller. The stern-drive unit can be treated like an outboard motor, and can be used to pivot the boat, even without a rudder.

The most renowned stern-drive brands are MerCruiser stern-drives from Mercury Marine and Volvo Penta of the Volvo group.

Stern-drive units act as replacement to outboard motors and are relatively more advantageous in a number of ways. Stern-drives are sources of more driving horse power per engine and the outdrive installation requires no cutouts on the transom. Also, the absence of a protruding power-head makes the stern-drives a practical choice. Volvo Penta’s Diesel engine stern-drive, model code D6A-370 can even offer 370 horsepower driving force from its engine. Volvo Penta stern-drives are more popular in European Boating communities; while, MerCruiser stern-drives being more popular in the US market. In 1999 Volvo Penta group sued the MerCruiser manufacturers for monopolizing the stern-drives business in the US.

The main disadvantage of stern-drives to outboard motors is that they are relatively more exposed to the harshness of water. The out-drive is prone to corrosion and so the need for replacing them often crops up. There are certain safety hazards like the explosion hazard, which can be easily avoided if proper precautions are taken.