Hamilton Jet Rescue
Built for operating in rough seas with maximum power and maneuverability, the Sumner Lifeboat Institution's new vessel reinforces the benefits of water jet technology in rescue situations. Paul Smith reports.
Concept and design was based on extensive research. In addition to feedback from lifeboat crews' and the Institute's previous water jet propelled surf rescue boats, the SLBI was also aware of compliance requirements from both the Royal New Zealand Coast Guard Federation and the Maritime Safety Authority. It was considered these would be best addressed by a Naval Architect, with the vessel's subsequent construction to be subject to Survey.
The new boat would incorporate a number of significant design innovations that, in terms of its intended use, rendered the new craft very much a prototype. Once finalized, the brief was forwarded to Richard McBride who has a number of successful designs utilizing water jet propulsion.
One of the main developments in the design was the incorporation of "closed cell" foam fendering and the associated fixing system. Being a RIB, Caroline Nicholson used inflatable bags that were vulnerable to puncture when the vessel operated close in and against sharp, shell-covered rocks and when coming alongside of ships and wharves with sharp projections.
Other design features include modules that can be easily removed to facilitate access for maintenance, repair and replacement. For example, the center command console can be lifted out as a complete unit to access for'd areas of the hull and engine cover assembly for engine and water jet access.
The hull itself follows conventional design criteria - a deep vee monohedron. However, the complete design package has been configured to optimize performance of the boat in breaking surf conditions.
The tender to construct the new lifeboat was won by CWF Hamilton & Co Ltd subsidiary Hamilton Marine Ltd. The hull, deck, foc's'le assembly is constructed from fully-welded marine grade aluminum alloy to form a solid and rigid monocoque. All engineering construction is to Survey.
The foam fender system (supplied by Fender Solutions, a subsidiary of Christchurch's Butler Marine Ltd), has been implemented successfully in various military and oil industry applications in Singapore, Venezuela and Australia.
In New Zealand, a similar system was used by McLay Boats for their "McLay Softies", but the lifeboat's affixing system is unique in that the T-bar fender is bolted through the hull topsides from inside and the foam is used as a cushion against impact as well as offering additional buoyancy and therefore stability.
The fixing system allows the fenders or sections thereof, to be repaired or replaced in the event of damage. The D profile fenders remain constant in size from the transom to a point about three metres for'd, from where they then taper. This allows better visibility from the helm when maneuvering in closely confined quarters and produces less lift when the craft is operating in breaking surf, thereby reducing the likelihood of being tipped over end for end in a worst case scenario.
The "closed cell" foam is protected with an outer coating of "Rhino Lining" - a spray applied urethane the same as that found on deck linings of utility vehicles, which makes for easy clean and low maintenance.
The layout of the vessel is optimized to suit its intended use. The short foredeck has non-slip rubber over its entire area and this extends down each side deck. The small fore cabin provides a measure of shelter and is accessed via a solid alloy door to starboard of the helm. Around the main station, there are three waterproof storage lockers containing ready-to-use equipment such as flares, tow ropes, first aid kits etc, which allow the crew to access them without having to get into the fore cabin.
The centrally-mounted helm station allows the skipper to concentrate on helming the vessel without unnecessary distraction. Immediately in front of him is the GPS repeater, compass and control microphone plus alarms for bilge, engine coolant and oil pressure. The Morse forward/reverse control lever is ergonomically located with its own support rail, with a solid stainless steel helm. A foot throttle is preferred for greater control in difficult operating conditions. The skipper remains standing at all times and a solid, adjustable backrest provides support and stability when the boat is thrown about.
The master control station is monitored by the crew and is located in a centrally mounted console immediately aft of the helm station. It houses twin VHF radios, the engine instrumentation, the Navman Tracker 5600 GPS (linked to the repeater on the dash) and the actuator for the electric-over-hydraulic operated intake screen rake (to clear debris such as seaweed, rubbish etc, which could be ingested into the water jet).
A solid stainless steel towing post is centrally mounted and is detachable if required. The console supports solid alloy grab rails for the crew and the entire fo'c ‘sle is topped with similar grab rails.
The engine box console has a padded top which is level with the cockpit coamings allowing level stowage across the rear of the cockpit for stretchers, kayaks, surfboards and the like. Another locker immediately aft of the engine box gives access to the driveline and water jet, while the sand trap can be quickly viewed through a Perspex panel.
The cockpit sole is tread plate alloy and is self-draining with a large scupper in each rear corner. A large alloy framed boarding platform with teak slats is mounted across the transom above the water jet. In addition to boarding, it provides a measure of protection to the water jet steering nozzle when the boat is operated in close proximity to rocks, bluffs, wharves etc.
Engineering & Propulsion
Power is provided by a 5.7 litre Marine Power Jetpac multipoint fuel injected V8, based on the Chevrolet 350 Vortec small block. It develops 325hp and features a closed circuit heat exchanger cooling system.
It has been mounted a little further for'd in the boat to provide a more central Longitudinal Centre of Gravity. It has been coupled to the Hamilton Jet HJ213 water jet via a H-Bar shaft.
The HJ213 water jet has been specifically designed for permanent immersion in salt water and the shafting and bearing capacities have been upgraded so they are suitable for high load diesel engines. These jets also feature a hydraulically actuated forward/reverse bucket.
Other engineering solutions have been incorporated into this craft that are simple but effective. For example, if the sand trap is inadvertently left open (possibly depriving the engine cooling system of cold water) the main locker cannot be closed. This allows a simple visual check that all is OK.
Performance & Handling
Paul Lawson, SLBI Coxswain, is delighted with the performance, handling and overall capability of the new vessel. On her maiden voyage, "Hamilton Jet Rescue" was tested in a 3.5 metre breaking surf. Surf Skipper, Geoff Williams confessed to a little trepidation at first but this quickly gave way to excitement and delight as he explored the capabilities of the new craft.
On our demonstration run, the sea conditions off Sumner Bay were considerably less demanding, but a 1 to 1.5 metre swell gave us ample opportunity to see what this boat's about.
First impressions are the solid feel on the water with no annoying rattles or squeaks, the extreme manoeuvrability offered at all speeds, and in particular the ease of close quarters manoeuvres at displacement, where the hydraulic reverse bucket really shows it's worth.
Geoff was happy to demonstrate the grip of the water jet in the aerated water of the cresting waves on the Sumner bar. He showed us the jet boat's ability to quickly bear away from any particularly threatening waves and, of course, the jet's ability to operate satisfactorily in quite shallow water.
In these conditions the water jet stands head and shoulders above outboard powered RIB's, making a nonsense out of that silly myth that "jets are no good in the sea". One of the other important considerations of water jet propulsion in this type of application is the ability to come alongside people in the water without fear of causing injury with the exposed propeller.
The overall balance of the craft was also evident in a following sea with no tendency whatever toward broaching when surfing down the front of some larger swells. The boat tracked straight and true.
"Hamilton Jet Rescue" is the latest in a long line of surf rescue boats operated by the Sumner Lifeboat Institution Inc, and she incorporates many of the worthy features of her predecessors. However, there is sufficient design and engineering innovation to classify the boat as a "prototype". It would be hard to ignore this craft as now being a blueprint for future surf rescue craft for other units around the country.
It should be noted that the sponsorship agreement between SLBI and Hamilton Jet was negotiated separately to the purchase of Hamilton Jet Rescue and is not representative of a "discounted" supply. It is a reflection of Hamilton Jet's belief that the naming rights of this vessel provide an excellent opportunity for the company to demonstrate the capabilities of its product in the most demanding situations while at the same time being able to assist a deserving local organization.
|Hamilton Jet Rescue Specifications|
|Design: McBride Design, Nelson|
|Boat: Hamilton Marine Ltd, ChCh|
|Water jet: CWF Hamilton & Co Ltd, ChCh|
|Trailer: Jetstream Services Ltd, ChCh|
|Engine: Performance Engine Centre Ltd, ChCh|
|Electronics: Ocean Electronics Ltd, ChCh, Tait Electronics Ltd, ChCh|
|Fendering: Fender Solutions, ChCh|
|Engineering Solutions: Wood & Thompson, Marine Engineers, ChCh|
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