Jet Boat Project
About the project
Welcome to the Jet Boat Project Website. This is a documented
project about the restoration and conversion of an old propeller
driven speed boat into a water-jet propulsion system.
The boat was originally a 1971 15.5ft Scorpio Craft fitted with a 90HP OMC (Outboard Marine Company) Stringer Electromatic Stern Drive. The original OMC power unit was a marinised version of the popular Ford Pinto type 1600 OHC 4 cylinder engine. These have now been replaced with a Rover 3.5L V8 engine driving a Hamilton 771 Series Jet Drive.
The project was meant to be a usual rebuild and restoration, but trying to keep everything as original as possible. Having previously owned speed boats with outboard motors, I wanted to rebuild one with an inboard motor. Inboard speed boats are usually more expensive than the outboard versions so my intension was to rebuild an old one over a period of time to spread the cost.
As with most projects like this, the aim is to be cost effective but not to skimp on quality or safety. A very good way to get new parts at a very reasonable price is to search the Internet auctions. Here you can get new parts cheaper than some dealers are asking for used or second hand ones. The majority of parts were bought through the Internet and some from local boat jumbles.
The above boat was purchased and stripped down to the shell, with all of the interior and fittings being discarded as they were rotten, broken or worn.
One of the first stages of the project was to make sure the OMC engine and Stern drive was serviceable. Although the engine was old, obtaining parts wasn't a problem as this was a common engine and the marinised parts were still serviceable. The Stern Drive was going to be a little trickier as the OMC company had gone bankrupt in December 2000 but parts were still available. Both were stripped down and a list of parts gained for the rebuild.
The OMC Stern Drive needed new bearings throughout and a complete new water pump. Whilst searching the Internet using the word pump, I came across a new Hamilton 771 Jet Drive for sale, these are specially designed propulsion systems used on Jet Boats which are commonly referred to as pumps. These devices suck water in from a hole (intake) under the boat and is then pumped at high velocity through the rear (stern) of the boat to push it forward.
Purchasing this new jet drive to replace the old OMC Stern drive added the word conversion to the project taking it to an entirely new level, so the idea of keeping things original went out of the window. This was just as well as I could now do my own thing. Now that the drive system was going to be changed, a more powerful V8 motor seemed appropriate and well within the scope of the project. The old OMC engine was scrapped and the Stern drive was sold.
All that remained of the original boat was the fibreglass hull, the Triplex glass windscreen and part of the main wiring harness. The project has taken over 7 years so far. Most of the work has been completed by myself with the appreciated help from friends and family.
If you have any pictures or information you would like to share regarding the make or model of this boat, please mail me, I'd be very interested to know and perhaps I can add a viewer's page later on.
Here is a video of the boat in action during a family day out at Cardiff Bay.