What is a ‘Jet Powered Vessel’ and why do we use them?

A ‘jet drive’ in the marine industry is a water pump that generates a high speed jet of water which is ejected through a nozzle that has directional control for steering. This creates a thrust force pushing the vessel forward as a propeller would do. There is also a ‘bucket’ which deflects the jet of water to move the vessel aft, and in combination with the directional nozzle, port and starboard.

The jet of water is created by an inboard engine turning a drive shaft which an impeller is mounted to. This impeller takes water from underneath the hull and forces it out through the nozzle. The two inboard engines we have on CRC Galaxy for example are 435 horsepower each and reach 3,500 revolutions per minute. With up to 6 blades on the impeller, that makes for a powerful drive system!

The controllable bucket provides very responsive steering and if you have two jet drives on one vessel as we do, you can use the drives independently of one another, creating an extremely manoeuvrable vessel which turns 360 degrees on its own axis. This is vital for us when tasked on work sites confined in space.

Commercial Rib Charter cater for a wide range of tasks including shallow draft crew transfers, dive support services and nearshore cable landings. Many of these projects are carried out in shallow water where the jet units come into their own. Compared to a vessel using propellers, jets require much less water under the hull and can safely operate with less than a metre of depth.

So which jet units do we use?

We operate three types of jets in our fleet – Hamilton Jets on our three Cabin Ribs, CRC Voyager, CRC Galaxy and CRC Tempest; MJP Ultrajets on our catamarans CRC Gladiator and CRC Vulcan; and Rolls Royces on our 20m flagship, CRC Sentinel. Each have their own benefits and all feature state of the art equipment and control systems.