Boomeranger Boats put Kongsberg’s Kamewa A5 waterjets to the test – this is what they found
When you sell RIBs and patrol vessels to navies, coast guards, and special forces, you need to be sure that every component works perfectly.
That is why Finland’s Boomeranger Boats, which specialises in fast patrol craft, turned to Kongsberg’s A5 series of waterjets to propel a new boat designed for special forces teams and rescue missions. Boomeranger has been testing the A5 on its new boat and has a real-world report of the new waterjet series in action.
Acceleration and handling
“Compared to the old FF series, there have been huge benefits. The acceleration is perfect – it really accelerates like a stern drive boat. The handling is very good,” says Jari Saari, Project Director, Boomeranger Boats. The A5 exceeded Kongsberg’s own predictions on thrust and acceleration as well as Boomeranger’s speed estimate and their requirement for maximum speed.
The principal benefit of a waterjet has been its high speed and use in shallower waters due to reduced draught and excellent and unique manoeuvrability. Buyers can now add improved thrust to the list of benefits.
Boomeranger installed the A29-5 on one test boat and a stern drive on an identical test boat to compare the performance. “I cannot differentiate between them (stern drive or waterjet) anymore, as I would have done 10 to 15 years ago.”
The acceleration is perfect – it really accelerates like a stern drive boat. The handling is very good.
While performance has been improved, Kongsberg is always aware of the need to reduce the space required for installation as much as possible.
Such compact construction is a big advantage to boat builders, who themselves are often under tight specification parameters. Saari points out that for Boomeranger’s latest project, the A5 waterjet had to be “pulled in” 30 centimetres to keep within length restrictions. Saari reports that mechanics can still access every key maintenance item on the test boat’s waterjets, despite the reduced working area.
Kongsberg has also made the A5 series easy to install. “There are good instructions and good support if we have some questions or some issues,” says Saari. “The Kongsberg guys are always there to provide help and support.”
"When the end users are happy, then we know that we have succeeded in something. We are so happy with this new waterjet so hopefully Boomeranger will deliver as many boats as possible with the new A5-series."
Handling in tough conditions
Another key benefit of the new A5 series is its ability to keep working at 100% output in wavy conditions. During Boomeranger’s test trials of the new A5, the test boat encountered choppy waters. Saari says that some waterjets can lose thrust in such conditions, but the A5 did not lose any thrust, even in steep waves.
Boomeranger Boats need to pass the SOLAS (Safety of Life at Sea) tests, which include a three-metre drop, aft first, into the water. This is to ensure the vessel can be used in rescue missions even when evacuations are done in heavy seas. Saari reports that the A5 passed the test on the trial boat without any issues.
Boomeranger needs to satisfy the world’s toughest clients, and Saari says that for waterjets, Kongsberg has been a trusted supplier for years.
“When the end users are happy, then we know that we have succeeded in something. We are so happy with this new waterjet so hopefully Boomeranger will deliver as many boats as possible with the new A5-series.”
The new A5 series is the result of three years of research by Kongsberg, is available for boats up to 25 metres. The A5 series is manufactured in high-grade marine aluminium and available in seven sizes, for power outputs ranging from 100kW to 1230kW with speeds between 25 to 40 knots.