The following extract was taken from a paper presented to the ninth international life-boat conference in Edinburgh, 1963, by Lieut.-Commander Robert W. Witter, Chief, Boat Section, Naval Engineering Division, United States Coast Guard.

THE ability to operate satisfactorily in coastal waters under unusually severe adverse weather and sea conditions was a major consideration for the new 44-foot life-boat built by the United States Coast Guard. Features intended to provide excellent seaworthiness char- acteristics were given high priority in the development of the preliminary design. In the forward sections of the hull, emphasis was placed on lines favourable to easy driving with a mini- mum of pounding in a seaway. This new boat followed the important sea- worthiness requirement of a small moderately fast Coast Guard craft in its ability to proceed into head seas at a maximum speed consistent with due consideration for damage to the boat's structure and equipment and a mini- mum of physical punishment to the crew. The adequacy of these design considerations was confirmed in evalu- ation trials following construction of the full-scale boat.

In the determinations of hull scant- lings emphasis was placed on highest strength obtainable in the least practic- able weight considering the most severe service conditions of rescue at sea, possible grounding, working in ice, heavy surf, and towing assistance. The hull, which is framed by a combination of transverse and longitudinal mem- bers, is divided into seven watertight compartments. For safety against possible grounding damage, a double bottom is provided in the forward half- length of the boat. Further grounding protection, when broached, is afforded by a web frame located at the mid- section and extending from keel to cockpit deck level.

Bulkheads are constructed of mild steel, as are the hull framing, raised decks and cockpit deck. The shell plating is constructed of in. Corten steel, a special low carbon formulation possessing high strength and cor- rosion-resisting properties.

The trunks over the mess and pas- senger space and the litter space are constructed of aluminium alloy 5086- £[32. The trunk over the machinery space is constructed of mild steel. The windshield, dodgers and other parts of the superstructure are constructed of aluminium alloy 5086-1132.

PASSENGER SPACE The steering station is equipped with engine throttle and starting con- trols, steering wheel, instrument panel, special-damped compass, and remote- operated electronic equipment.

The passenger space includes two transom seats, fitted with foam rubber cushions and six auto-type safety belts.

The mess space is similarly equipped with a single transom for accommo- dating three persons, in addition to including limited galley facilities con- sisting of a dresser with sink and hot cup receptacles. An enclosed toilet- space is located convenient to this liv- ing area. The litter space includes two transom seats with safety belts for five persons. Stowage is provided for a Stokes litter and fire-fighting chemical foam.

ENGINE POWER The main propelling machinery con- sists of two diesel engines each pro- ducing 200 shaft horsepower, which are remotely controlled from the steering station by single lever control for both clutch and throttle. Each engine drives a monel propeller shaft through hydraulic reverse reduction gears. The propellers are three-blade cast manganese bronze. The shafting is supported on water lubricated cut- lass rubber bearings.

Each engine is equipped with a 2000 watt, 28 volt D.C. alternator with a rectified output and voltage regulator to supply auxiliary electrical power to the boat. Service electricity is control- led and supplied through a distribution switchboard to two 750 watt converter units for 115 volt A.C. power to oper- ate the electronics equipment. Batter- ies are installed to provide "dead-boat" communications capability.

Starting for the main engines is by means of a hydraulic system with controls to actuate remotely the start- ing motors. Stored pressure accumula- tors provide starting reserve during stand-by engine status.

The port engine has a manual clutch-type power take-off for opera- tion of a 120 G.P.M. fire and salvage pump. This engine also drives the hydraulic starting system pump and air compressor. The starboard engine drives the hydraulic steering system pump.

CHIEF STATISTICS The boat is provided with twin, balanced foil plate rudders of welded construction and controlled by means of a cable system with power assist from the hydraulic steering booster.

Quick and precise rudder action is thus afforded.

Towing equipment consists of the 4-in. diameter tow bitt and tow line stowage reel with 100 fathoms of 3 in.

circumference nylon rope. Double bitts are located at each side for side tow positioning.

Minimum hull maintenance is ex- pected from the utilization of "exotic" paint coating systems for all interior and exterior surfaces of the hull.

Principal dimensions and character- istics as developed from design and construction stages are as follows: Length, overall Length, design waterline Beam, overall Beam, waterline Draft Displacement Fuel capacity Water capacity Shaft horsepower, maximum Trial speed Endurance Block coefficient Prismatic coefficient Midships coefficient 44' I0i" 40' 12' 8" 10' 10' 3' 2f 15-8 tons 333 U.S.

gallons 16 U.S. gallons 400 15-3 knots 290 miles, 10 knots 163 miles, 15 knots 0-38 0-52 0-73 Range of stability, in excess of 175 degrees G.M. (metacentric height) I-8 feet K.G. (distance from centre of gravity to bottom of keel) 4-8 feet Adequacy of stability calculations and confirmation of self-righting capability were checked during cap- sizing test. This test indicated approxi- mately two or three seconds were required for return from overturned to upright position. Self-bailing of the midships cockpit is achieved through the four-inch diameter, non-return ball-check scupper valves. Approxi- mately 55 seconds elapsed in clearing water scooped in capsizing test..