Special Purpose Craft – Shallow Water (SPC-SW) Patrol Craft

Special Purpose Craft – Shallow Water (SPC-SW) is a multi-mission in-shore patrol craft designed and manufactured by Metal Shark Aluminum Boats, for the US Coast Guard. The patrol craft can be deployed for multiple homeland security missions including search-and-rescue (SAR), maritime law enforcement, combat craft and ports/waterways/coastal security.

The vessel is capable of performing operations in shallow waters of up to 18in (1.5ft) at low speeds.

Orders and deliveries of SPC-SW patrol craft

Metal Shark was awarded a contract by the USCG Office of Boat Forces to build a total of 90 SPC-SW patrol vessels in September 2008. The USCG will deploy 40 units, while the remaining will be deployed with the Customs and Border Protection. The first craft in the fleet, Coast Guard 24500, was commissioned in 2008.

SPC-SW patrol craft design and features

The SPC-SW multi-mission response boat is based on the Metal Shark 24 Relentless standard platform. Its hull features a hard chine planing boat design made from marine grade aluminium alloy. A cathodic protection system is installed to protect the exterior surfaces of the hull.

The vessel can be transported on public roads by a trailer developed by AmeraTrail. The overall length of the vessel is 27ft, while the beam is 8ft 3in, height is 12ft 9½in, and draft is 1ft 6in. The vessel weighs 6,880lb and incorporates non-skid, aluminium decks and gunnels.

The patrol craft is equipped with two shock-mitigating patrol seats and two jump seats accommodating a coxswain, a boat crew member, and up to two additional crew personnel or passengers while executing high-speed mission duties. It can also carry up to six additional personnel.

Other equipment fitted to the vessel include a partially-enclosed centre console with an aluminium canopy, lighting systems, fire extinguisher, two 12VDC submersible bilge pumps, bilge pump panel, windshield wipers and washers, and an anchoring system.

The SPC-SW also incorporates three 12VDC marine grade lead-acid batteries, including a port engine starting battery, starboard engine starting battery and a dual-purpose battery. It can also be fitted with mounted automatic weapon and a tripod gun mount on the forward deck.

Communications / navigation systems

The shallow water patrol craft is equipped with standard marine communications and navigation systems on the overhead instrument panel. The radio communication equipment fitted to the boat include Standard Horizon GX5500S VHF-FM radio, Motorola XLT-5000 VHF-FM radio and a Motorola XLT-5000 UHF-FM radio.

A Furuno LH-3000 loudhailer is incorporated to offer onboard and ship-to-ship communications and to amplify navigation horn signals.

The vessel is also equipped with a scalable integrated navigation system (SINS) consisting of 1834C/NT radar / chart plotter, magnetic compass, PG-500 heading sensor, RD-30 multi-functional display unit, depth & temperature transducer, GP-37 differential global position system (DGPS) System, and an L-3 ProTec-M automatic identification system (AIS).

SPC-SW propulsion and performance

The SPC-SW response boat is powered by two four-stroke, in-line, counter-rotating sea water cooled Honda marine outboard motors, which produce a power of 150hp each. The four-cylinder engine has a dry weight of 490lb and uses gasoline, which is stored in a 100-gallon aluminium fuel tank located under the foredeck in the hull.

The engines are mounted on a hydraulically-actuated single jack plate. The propulsion system also consists of electrical alternators and a stainless steel, three-blade fixed pitch propeller.

The patrol craft has a displacement of 7,800lb in fully loaded condition and a trailer load capacity of 10,800lb. The maximum and cruise speeds are 41kts at 6,000rpm and 30kts at 4,800rpm, respectively. The vessel has a range of 225nm at 4,800rpm in calm water. The maximum operating distance from shore is 5nm.