The largest marine waterjet propulsion units ever built by HamiltonJet left from its New Zealand factory recently for South Korea, as part of a multi-vessel high speed patrol boat project.  The first pair of HamiltonJet model HT1000 waterjets, each with an inlet diameter of  1m, is the culmination of two years of design and construction.

 

HamiltonJet Technical Manager Phil Rae says the design of the HT1000 waterjet is quite different to the company’s other waterjet models and those manufactured by European competitors, but its innovative design offers many performance and operational benefits.  “These units provide high performance across a wide vessel speed range and excellent manoeuvrability. They have been designed with on-board hydraulics and a fully electronic control interface, ensuring installation and maintenance is very easy for the shipbuilder”.

 

The HT1000 has been designed and built specifically for a new fleet of 58m patrol vessels operated by the Korean Coast Guard.  “We’ve had the basic design concept in mind for a couple of years, but with the high costs involved in tooling and setting up the production for a new design we’ve been waiting for an appropriate project which would allow us to go the next step,” says Mr Rae. 

 

Each of the 300 tonne-class steel patrol vessels will have two HT1000 waterjets plus a central pair of smaller HM811 boost waterjets, driven by four 2.7 MW (3650hp) diesel engines to give a top speed of 35 knots. 

 

“One of the unique operating requirements of this patrol vessel is the need to operate on the two wing waterjets only, at a speed of at least 20 knots. This required a jet size well above the company’s largest current waterjet model,” says Mr Rae. 

 

The new HT1000 unit features a high efficiency “mixed flow” pump that is more compact than competing waterjet models, and advanced computational fluid dynamics (CFD) software was used extensively in its design. Thrust vectoring is achieved by a unique internal pivoting nozzle arrangement that deflects the entire water flow of each jet to port or starboard for steering, and a split-duct deflector for reversing the water flow for ahead / astern thrust control.

 

The vessels diesel engines, gearboxes and waterjets are controlled using a integrated networked digital electronic control system. The thrust vectoring capabilities of the waterjets allow a vessel to stop very quickly (within 1-2 boat lengths), turn on the spot and move sideways, which is not possible with conventional propellers.

 

HamiltonJet Marketing Manager Mike Shearer says the HT1000 marks a significant milestone for the company in its design and manufacturing capabilities. “This is a new level of waterjet size and a new class of patrol boat for the Korean Coast Guard, which opens up many opportunities for HamiltonJet,” says Shearer. “We have been working with the KCG for many years, and currently have many waterjets operating in its 50T class patrol boats, as well as twin HM811s in the first two of a new fleet of 100T class patrol craft. But this 300T project sets a new benchmark and has given us a great opportunity to take the next step forward.”