Hamilton Jet Rescue is a purpose-designed surf rescue boat, water jet powered and with closed cell foam fendering.
Hamilton Jet Rescue has played a key role in SLBI’s ability to respond to surf and inshore rescues since its delivery in 2005.
This article by Paul Smith discusses the vessel’s design, construction, handling and performance.
Planning for and construction of the new craft took around three years.
One of the SLBI Management Committee’s main aims for the project was that Christchurch-based suppliers would be utilized as much as possible. This would allow the Committee to more easily track the project and to implement design solutions as construction proceeded to suit their specific requirements for the boat.
THE NEW BOAT ON WHEELS
In addition to the feedback gained from lifeboat crews and their experience with previous water jet propelled surf rescue boats, the committee was also aware of compliance requirements from both the Royal New Zealand Coast Guard Federation and the Maritime Safety Authority. It was considered these could be best addressed with the use of a Naval Architect to design the vessel and its subsequent construction to be subject to Survey. For the Institute, 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 to his credit 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. ‘Caroline Nicholson’ being a RIB, used inflatable bags that were vulnerable to puncture when the vessel operated close in to 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 as required. 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 being a deep vee monohedron. However, the complete design package has been configured to optimize performance of the boat in breaking surf conditions.
THE NEW BOAT
The tender to construct the new lifeboat was won by CWF Hamilton & Co Ltd subsidiary Hamilton Marine Ltd. This company has a long history of custom and production boat building and has supplied goods and services to the SLBI for a number of previous projects. In addition, it has an excellent and longstanding working relationship with McBride Design.
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 and no compromises were made in regards to ensuring the vessel is plenty strong enough to cope with the adverse sea conditions it may be required to operate in.
The foam fender system supplied by Fender Solutions, a subsidiary of Christchurch’s Butler Marine Ltd., is not new having been implemented successfully in various military and oil industry applications in Singapore, Venezuela and Australia. In NZ, 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 3 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 HAMILTON JET AT FULL SPEED
The layout of the vessel is again 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 is also optimized to allow the skipper to concentrate on helming the vessel without unnecessary distraction. Immediately in front of him is situated the GPS repeater, compass and control microphone plus alarms for bilge, engine coolant and engine oil pressure. The Morse forward/reverse control lever is ergonomically located with its own support rail while the helm is solid stainless steel. 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 is has a padded
top which is level with the cockpit coamings allowing level stowage across the rear of the cockpit for such things as stretcher(s), 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
The engine is a 5.7 litre Marine Power Jetpac multipoint fuel injected V8 based on the Chevrolet 350 Vortec small block. The engine was supplied by Marine Power agent, Performance Engine Centre of Christchurch and develops 325HP. The engines are a turn-key marine package and this one features a closed circuit heat exchanger cooling system.
The engine has been mounted a little further for’d in the boat to provide a more central Longitudinal Centre of Gravity and is of benefit in this type of application. 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 which is of particular benefit in this lifeboat application.
Other engineering solutions have been incorporated into this craft that are simple but extremely effective. For example, if the sand trap is inadvertently left open (thereby possibly depriving the engine cooling system of cold water) the main locker cannot be closed. This provides a simple visual indication that something is not as it should be and could prevent an engine failure.
Performance & Handling
AN EXCELLENT PERFORMER
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 admitted 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 allowed us to get accustomed to the boat. First impressions are the solid feel of the boat on the water with no annoying rattles or squeaks, the extreme maneuverability offered at all speeds, but in particular the ease of close quarters maneuvers at displacement where the hydraulic reverse bucket really shows it’s worth, and the thrust when the throttle is opened from 3000 rpm.
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 ability of the jet boat to quickly bear away from any particularly threatening waves and, of course, the jets 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 potentially serious injury by 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’ in terms of her intended use. The performance of the craft to date has more than justified the Institution’s faith in all the suppliers and contractors involved in this project and it would be hard to ignore this craft as now being a blue-print 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.
Suppliers to Hamilton Jet Rescue
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