The extension tube is machined from a solid piece of bronze to precise tolerances. It moves the shaft bearing back six (6) inches. This allows for a larger diameter propeller to be turned, facilitating the conversion to a lower RPM diesel. The installation is straight forward, and the process takes no more than half a day.  Alignment is assured because the extension is a slip fit into the stern tube. It is secured with set screws then epoxy and glass mat (complete instructions are supplied with purchase) that are used to fair it to the hull. The extension tube is supplied with a shaft bearing and stainless steel set screws. -  Request Current Pricing.