Different types of boat propulsion systems exist, and to help better understand these systems we have produced a glossary of common terms.
Outboard Motors, Stern drives (also known as Z Drives), Surface drives and Jet drives are not catered for by our Strippers and therefore not discussed any further.
Conventional drives have an engine and gearbox mounted inside the boat.
The propeller shaft is connected to the gearbox output flange by a half coupling which in turn is mounted on the propeller shaft, there may or may not be a flexible coupling in between.
The image on the right shows a typical installation without a flexible coupling.
One of our Spacemaker shaft extension kits has been added to enable extra space for the Stripper.
The shaft will leave the machinery space and enter the hull via a stern gland, the stern gland is there to seal the hull against ingress of seawater.
There are many different types of these available and other common names for variants of this device are Stuffing box, Packed gland and Face seal.
The gland is usually secured to the shaft log which is a hollow tube which extends aft.
The shaft will emerge from the hull through the shaft log and may or may not be supported at this point. If it is supported then usually this is by means of a Cutlass Bearing which is held securely inside an outrigger bearing housing, pictured right.
Another common variation is simply to have some of the shaft log extend beyond the hull and have the Cutlass bearing embedded inside it.
The log is commonly made from bronze or stainless steel, although GRP is becoming more frequently used, and in some instances a composite.
If the shaft is not supported then it will continue aft until it is held in a bracket mounted just forward of the propeller.
This bracket will contain a cutlass bearing and if it is a single strut is known as a P bracket, pictured right.
If there are twin struts then this is commonly known as an A bracket.
The saildrive driven boat has the engine and gearbox mounted inside the vessel the same as the conventional shaft driven boat, but instead of a propeller shaft exiting the hull rearwards the drive is taken out through a leg that sits vertically under the hull with the propeller mounted on it.
Common saildrive legs are made by Volvo, Yanmar and Buhk with the most common being Volvo. The image on the right shows a Yanmar saildrive with a Kiwiprop and Stripper installed.
Installation of a saildrive Stripper requires the removal of the propeller unlike the conventional shaft Stripper, however all saildrive legs have anodes that need to be replaced regularly which also require removal of the propeller.
The one exception to this is the latest Volvo 130, 140 and 150 saildrive leg where the anode splits allowing it to be replaced with the propeller still installed.
The other area that can cause confusion when ordering spare parts, or planning the installation of a Stripper is the naming of Stripper parts.
Click here to see all the Stripper parts listed with their correct name.