Cummins Mercruiser Diesel (CMD) has taken a giant swipe at Volvo¿s increasing market share in releasing its new Zeus pod drive system. The new CMD system has been developed in a tri-party manner with ZF Gearbox Company and the Brunswick corporation, the world¿s largest pleasure marine company.

The Zeus system enables the propellers to swivel independently in different directions at the same time. The person at the helm can control the direction of the boat at low speed by using a joystick. The need for a bow or stern thrusters is completely eliminated with the boat able to transverse sideways through the water.
While Volvo has clearly had the jump on its competitors for almost four years with its IPS system it appears that it¿s the old case of someone taking a good idea and made it into a great idea. While both systems capitalise on the benefits of horizontal thrust through counter rotational propellers compared to the conventional shaft systems with single propellers, it would appear that the similarity ends there.

The CMD system has rear facing propellers as opposed to the Volvo system where the propellers face forwards. While both parties argue the technicalities of the thrust delivered by their opposing systems the one question that we are all concerned with is what happens to your propellers if you hit something? CMD are quick to point out that they believe that their rear facing propellers are far less likely to suffer impact damage with them being rear facing and also being recessed into tunnels.

It would appear that on this issue Cummins really have the jump on Volvo. The Volvo propellers protrude from the bottom of the hull and being forward facing are venerable to strikes. Cummins have cleverly almost eliminated the problem by designing Zeus to sit in recessed tunnels in the hull. Utilising this design only the skeg of the drive protrudes below the keel line of the boat.

¿It¿s the old case of someone taking a good idea and made it into a great idea.¿
With the benefit of foresight Cummins also modified the clutch system on the gearbox with a trolling valve. This allows enough slip to have the propellers revolve at ultra low speed. There is no need for the operator to have to switch between high gear. This enables the skipper to very gently ¿push¿ the boat in a consistent manner as opposed to having to power on and off repeatedly to execute a manoeuvre.

Most impressively the Cummins system has the ability have the boat hover in a stationary position at the push of a button. By utilising an electronic compass in conjunction with a GPS signal the boat uses similar technology that enables helicopters to remain stationery. Even in a strong side breeze the boat is able to maintain its position.

Sea Ray are the first of the Brunswick brands to incorporate the Zeus drive system in its design. Challenge Marines Business and Development Manager Stephen Wren confirmed that the company had two Zeus powered boats arriving in May 2008.

People interested in test driving the Zeus powered Sundancer are invited to contact Stephen Wren at Challenge Marine on 92408060.