The Aqua Tow Project

In 1981 we installed an above ground pool in the backyard of our home in Melbourne, and with the family being keen swimmers it provided many hours of fun and exercise. It occurred to me that I could create an electrically powered tow for use in the pool, at the beach and in the surf.  Without realising what that entailed, I prepared a few sketches of a suitable shape for the hull along with a suitable propulsion system and guard as well as controls. Once the kids saw these there was no turning back. 

The mould patterns needed to be full size for creation of both the upper and lower hull mouldings. A high density rigid foam was used which was painted and finished to Auto grade quality. This allowed  Female moulds to be taken from them, and were used to create the final male moulds in fibreglass as production masters.  The next step was to find a suitable propulsion motor and controller and the Mercury electric outboardThruster” (modified) was mounted via the grey flange between the twin hulls.        

The batteries to power the Thruster were 80 x “D” cell size rechargeable NiCads arranged in packs of 10, wired in series and then in parallel giving 12.5 volts and 32 amp hour = 400 watts of energy. These could power the tow for 3-4 hours continuously. For balance there were 40 batteries in each side of the hull.           

The upper section of the hull was empty space and inside was an inflatable bladder which could be filled with water, thus achieving neutral or negative buoyancy. This would allow the rider, equipped with a snorkel and face mask to cruise around below the surface. The bladder could be filled via the red tap on the LHS of the Tow. The Aqua Tow rider floated in the water behind the craft with outstretched arms gripping the handlebars, this enabled easy steering. Power was controlled via a twist grip on the RHS. Preliminary test drives were carried out by our 6 year old daughter riding around the pool many times. The next test was my turn, riding out into Port Phillip Bay and boarding a rusting ship (Cerberus) scuttled 200 metres offshore, all went fine on the maiden voyage out but on the return trip I decided to open the buoyancy valve. Shortly after the Aqua Tow began to lose power as an internal leak allowed salt water to enter the battery compartment causing problems with the control circuitry and corrosion. The Aqua Tow is still awaiting design improvements and modifications which may happen in the near future.