Feature 1 | PATROL AND RESCUE BOATS High hopes for demo patrol boat
Mixing side window visibility at 0.8m with extensive interior headroom of up to 2.2m, MetalCraſt’s 9.95m loa 32’ Sentry prototype has challenged a number of preconceptions about aluminium craſt of this size.
L
aunched in prototype form at the beginning of December 2011, the 32’ Sentry patrol boat, designed by
Florida-based MetalCraſt Marine and built by MetalCraſt in association with Brunswick Commercial & Government Products, is intended to match typically fast response vessel speeds with an increased layer of visibility within the wheelhouse, as well as to realise a saving in vessel weight, whilst making the wheelhouse as secure, strong and spacious as possible. Te 9.95m loa, aluminium vessel has been
built in compliance with American Boat and Yacht Council (ABYC) directives, though Bob Clarke, contracts manager at MetalCraſt, tells Ship & Boat International that the 32’ Sentry exceeds some ABYC requirements. “The current ABYC H-1 Field of Vision from the Helm Position regulation specifies a distance of about four lengths ahead,” says Clarke, “but that is not going to cut it in rescue operations. Te pilot needs to be able to see his surroundings a lot closer than that. Te 32’ Sentry has been designed to grant the wheelhouse operator full visibility at 3m ahead onwards, and 0.8m onwards from the side windows. We have seen problems in the past
with patrol vessels attempting to rescue people from the water, only to miss these casualties completely, or even run the boat into them and kill them, due to restricted visibility from the bridge and sides – incidents of that kind greatly influenced 32’ Sentry’s design.” The boat features a beam of 3.38m, a
draught of 0.5m and can carry four members of crew and three passengers. One of the most notably immediate features inside the cabin, and a rarity for a craſt of this compact nature, is the abundance of space and the height of the cabin roof, with interior standing headroom measured at 2.2m aſt and 2.1m forward. Clarke says: “Having to stoop during operations isn’t just uncomfortable, but can cause long-term neck and shoulder injuries and soreness over time.” While headroom of 2.2m may seem excessive, Clarke adds that the height was calculated to account for operators wearing headgear and associated safety and protective gear. Additionally, the cuddy has two berths and room for an optional small galley, and features 1.88m headroom. Te aſt sliding cabin door and forecabin door have both been produced to a see-through design, with the aſt door granting crew complete views of the transom
The completed version of the MetalCraft Marine-designed 32’ Sentry prototype will be available in both outboard and diesel-waterjet configurations.
corners from the helm location. Lockers installed in the aſt cabin can house a small fridge and microwave oven to port and a locker for guns and clothing to starboard. For added crew spinal protection, shock mitigating seating is supplied by SHOXS.
Weight-reducing bends In order to adequately strengthen the wheelhouse to ABS standards, while simultaneously avoiding excessive weight through heavy welding, MetalCraſt decided the best course of action was to increase the use of bends in the cabin’s shape. Tis approach had two subsequent advantages. Firstly, it meant
that MetalCraft and
Brunswick were able to massively cut down on the amount of welding involved in the wheelhouse’s construction. Welding is always a tricky art when it comes to aluminium, with the process typically reducing aluminium’s inherent strength while upping the risk of causing ‘locked-in’ stresses, also known as distortion to the material caused by heat induction. Secondly, given that each bend can increase strength by as much as twice, it enabled the builders to work within a weight limit without sacrificing structural integrity. Te 32’ Sentry prototype is powered by
twin Mercury Verado outboard motors, each generating 220.7kW, although operators will be able to install triple outboards should they choose. Tese feed a pair of Mercury stained steel, fixed pitch propellers, with 380mm diameters, providing a top speed of 40knots. According to Clarke, when completed aſter its final round of extensive testing, the boat will be available in both outboard and diesel-waterjet versions. Although not fully decided as yet, it is likely that Cummins 59 engines will be matched with HamiltonJet HJ274 waterjets for the latter propulsive configuration, Clarke hints. Onboard electronics include Raymarine
radars and chart plotter, a Raystar 125 global positioning system (GPS) and an engine monitoring and fire detection system supplied by Vessel View. SBI
22 Ship & Boat International March/April 2012
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