Saildrive maintenance

Stu Davies shares his tips for making sure your boat's saildrive runs smoothly

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Maintaining a saildrive is just as important as engine care, given its role in ensuring smooth motoring.

I am most familiar with Volvo Penta saildrives so this article will focus on that make, but other manufacturers make them-all are basically of a similar design and layout.

Saildrives are the method of getting power to a propeller easily and relatively cheaply; cut a hole in the hull moulding, drop an engine and propulsion package in, seal with a big rubber gasket and that's it.

There are no shaft-to-propeller-to-engine alignment problems, no tricky throughhull tubes to align and no leaky propeller shaft seals.

Perfect... or are they?

However, like all things in life, they have issues. A saildrive does not need a deep water seal but it does have lip seals on the propeller stub shaft.

If you're unlucky enough to get a fishing line wrapped around the saildrive the seal will soon be destroyed, allowing seawater to enter the drive. This mixes with the oil in there to form an emulsion.

Saildrives are made of aluminium, a good, strong light metal but one which is easily corroded by seawater and other metals if steps are not taken to protect it.

They're bolted onto the back of the engine and have two right angle gears converting the drive from horizontal to vertical to horizontal again.

Saildrives have a forward and reverse gear, as well as four pinions to convert the drive to get the power down and out.