Motor life boat

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US Coast Guard Motor Life Boat CG-36535 off Nehalem River MLB Station, c. 1975
US Coast Guard Motor Life Boat CG-36535 off Nehalem River MLB Station, c. 1975

The Motor Life Boat (MLB) is an integral part of a coast guard fleet, built to withstand the most severe conditions at sea. Designed to be self-bailing, self-righting and practically unsinkable, MLBs are used for surf rescue in heavy weather.

The United States Coast Guard (USCG) and the British and Irish Royal National Lifeboat Institution (RNLI) have a long history with MLBs, from the early sail- and oar-driven lifeboats to the high-speed MLBs introduced in the 1990s.

The sailors of the MLBs are called "surfmen", after the name given to the volunteers of the original United States Life Saving Service (USLSS).

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[edit] Background

The first lifeboat is credited to Lionel Lukin, an Englishman who, in 1784, modified a 20-foot Norwegian yawl, fitting it with water-tight cork-filled chambers for additional buoyancy and a cast iron keel to make the boat self-righting.

These lifeboats were manned by six to 10 volunteers of organizations such as the RNLI and USLSS who rowed out from shore when a ship was in distress and risked their lives in order to save the lives of the unfortunate souls on board.

In 1899, a two-cylinder 12 hp (9 kW) engine was fitted to a 34-foot (10 m) lifeboat on Lake Superior, Michigan, by Lake Shore Engine Company at the behest of the Marquette Life Saving Station. Its successful operation marked the introduction of the first Motor Life Boat and soon more and more lifeboat stations fitted their lifeboats with engines.

By 1909, 44 boats had been fitted with engines, whose power had increased to 40 hp. The USLSS and the Revenue Cutter Service merged in 1915 to form the United States Coast Guard, as early predecessors of the 36 MLB began to take shape.

[edit] Early motor life boats

USCG MLB CG-44581
44 Motor Life Boat
First built: 1962
Last built: 1972
Number built: 110 by USCG, 52 under license
Builder: Coast Guard Yard, Curtis Bay, Baltimore, MD
General characteristics
Displacement: 18,500 lb (8400 kg)
Length: 44 ft 1 1/2 inches (13.4 m)
Beam: 12 ft 8 in (3.8 m)
Hull: Corten Steel
Propulsion: Two Detroit diesel 6v-53 185 horse power (153 to 186 kW) GM
Speed: 14 knots (29 km/h)
Range: 190 nautical miles (350 km)
Righting capability: Rollover in 8-15 seconds
Complement: 4 crew

The 36 foot T model was introduced in 1929. At 36 ft 10 in length overall, 10 ft 9 in beam and with a two-ton lead keel, she was powered by a 90 hp (67 kW) Sterling gas engine and had a speed of nine knots (17 km/h). From the early days of the 20th century the 36 MLB was the mainstay of coastal rescue operations for over 30 years until the 44 MLB was introduced in 1962.

Built at the Coast Guard Yard in Curtis Bay, Maryland, 218 36 T, TR and TRS MLB's were built between 1929 to 1956. Based on a hull design from the 1880s, the 36 TRS and her predecessors remain the longest active hull design in the Coast Guard, serving the Coast Guard and the Life Saving Services faithfully for almost 100 years, the last one, CG-36535, serving Depoe Bay MLB Station in Oregon until 1987.

The crews manning these boats typically had experience on local waters and had leadership from seasoned veterans whose boat handling skills were passed on directly to each new crewmember.

Localized training conducted at each unit allowed these crews to share their experiences and techniques. During the 1960s the Coast Guard replaced the 36-foot (11 m) MLB with the newly designed 44 foot (13 m) boat. These steel-hulled boats were more capable and more complicated than the wooden lifeboats they replaced.

While some coxswains resisted the new boat, holding on to their old 36s for as long as possible, claiming her canoe stern and aft cockpit to be favorable to the rounded stern and center helm station of the 44s, the 44 design is still in use today as many decommissioned models have been transferred to foreign maritime services.

Designed to return to an upright position in 8 to 15 seconds and with twin GM Diesel engines making 14 knots, she was bigger, faster and stronger than her wooden predecessors. Gold Lifesaving Medal recipient Boatswain's Mate First Class Bernie Webber who rescued 32 men from the tanker Pendleton with CG-36500 in 1952 had this to say about the 44 MLB in his book "Chatham: The Lifeboatmen":

"This new 44-footer was in sharp contrast to the old 36-footers like the CG36500. She was built of steel and powered by two GM diesel engines. She had two heated compartments for survivors, with settees and seat belts to hold them in safely during a rough passage. Unlike CG36500, which had only a compass for navigational equipment, the new 44-footer had an array of electronic aides. She was equipped with radar, direction finding equipment, depth finding equipment, and several radios with various range and frequencies. The boat had an enclosed pilot station, and a seat for the helm with a safety belt attached. It was also designed to roll over and come upright again."

Her range of stability was in excess of 175 degrees and rated for surf conditions up 20 feet (6 m), seas up to 30 feet (10 m) and winds up to 50 knots sustained (93 km/h). Her crew of four could comfortably travel over 50 miles (80 km) offshore and tow vessels up to 125 gross tons.

In all 110 vessels would be built by the Coast Guard Yard in Curtis Bay between 1962 and 1972 with an additional 52 built by the RNLI, Canadian Coast Guard and others under license from the USCG.

One of four refurbished 44 foot patrol boats supplied to the Djibouti Navy
One of four refurbished 44 foot patrol boats supplied to the Djibouti Navy

Still in active service, the 44 MLB can be found in many third world countries and faithfully serving the Royal Volunteer Coastal Patrol in Australia, the Royal New Zealand Coastguard Federation, and even the US Coast Guard Station Chatham in Chatham, Massachusetts where CG44301 (the first production 44) is still in active service. The current engine configuration is twin Detroit Diesel 6v53's that put out 185 hp each at a max RPM of 2800.

Another surf capable boat that the Coast Guard has used in recent years is the 30' Surf Rescue Boat (SRB) . Also self righting and self bailing, the 30' SRB was designed with marked differences from the typical lifeboats used by the Coast Guard up until the early 80's. The 30' SRB is not considered to be a Motor Lifeboat, but it was generally used in a similar capacity. Designed to perform Search and Rescue in adverse weather and surf, the first 30' SRB was built by the Willard Boat Company in Fountain Valley, California. Much of the 30 footer's design centered around speed. The sides of the hull are made of 5/8" airex foam cored firberglass reinforced plastic (FRP), and the bottom of the hull is constructed of solid FRP molded in one piece. The boat is 30' 4" in length with a 9' 4" beam, and weighs a total of 11,500 LBS when fully loaded with gear and engine. The 30 footer has a single Detroit Diesel 6V92TI engine, configured by Johnson Towers rated at 375 horse power. The throttles are manually controlled, and the boat has a single screw and rudder.

When new, the 30' SRB's were rated for a top speed of 31 knots. Although in later years, most of the hulls fell prey to minor water intrusion into the FRP, which slowed most of the boats to around 28 knots at max RPM. The 30 footer has a range of 130 NM, and most standard operating procedures dictate that the boat not go more than 20 nautical miles offshore without a waiver granted at higher level commands. The fuel capacity is 78 gallons at 100%, and the vessel is generally operated with a crew of two, a Surfman and an Engineer. The crew both stand on the coxswain flat, protected by the superstructure on the bow and stern. The boat's appearance has caused many to comment that it looks like a "Nike Tennis Shoe".

The intent for the boat is that it be used for quick response. It is able to get on scene quickly, get into a surf zone and extract any persons in the water, or to stabilize a situation until the slower and larger Motor Lifeboat can get on scene. Since 1997, and the introduction of the faster 47' MLB, and the phasing out of the 44' MLB's, the need for a quick response vessel diminished, making the 30 footers obsolete. The class of vessels underwent an overhaul in the early nineties to extend their life until the newer and faster 47' Motor Lifeboats came into service, and in the late 90's most of the 30 footers were de-commissioned. One still remains on active duty at Motor Lifeboat Station Depoe Bay in Depoe Bay, Oregon and is used almost daily. Ironically, this station was also host to the last 36' Motor Lifeboat in the late 80's. Even though the boats have many quirks, including "dynamic instability" (where the boat becomes unstable at high speeds), many Surfmen who became qualified on the boats have sworn by them. Sometimes referred to as a sports car compared to a tractor (the MLB), they are sometimes challenging to learn to operate, but once mastered, the 30' Surf Rescue Boat is definitely one of the most seaworthy boats the Coast Guard has employed.

[edit] Modern motor life boats

A USCG 47 MLB
47 Motor Life Boat
First built: 1990 (prototype)
Last built: Still in Production
Number built: currently 117;
200 scheduled
Builder: Textron Marine
General characteristics
Displacement: 40,000 lb (18,000 kg)
Length: 47 ft 11 in (15 m)
Beam: 14 ft (4.3 m)
Draft: 4 ft 6 in (1.4 m)
Hull: 5456 marine aluminium
Propulsion: Two 435 hp (324 kW) Detroit Diesel engines
Speed: 25 knots (46 km/h) max; 22 knots (41 km/h) cruise
Range: 200 nautical miles (370 km) cruise
Righting capability: Rollover in under 10 seconds
Complement: 4 Enlisted Personnel (1 Coxswain, 1 Engineer, 2 Crew), 5 passengers

The USCG has since designed and built new aluminum 47 foot lifeboats, with Textron Marine and Land Systems awarded the contract to design and build the US model, which was delivered in 1990. After 2 years of testing and evaluation, 5 more were built between 1992 and 1994 incorporating improvements from the prototype model for further testing and evaluation around the country. The first production boat was delivered to the USCG in 1997.

The 47 MLB is the most sophisticated MLB ever built, able to withstand impacts of three times the acceleration of gravity, she can survive a complete roll-over, self-righting in less than 10 seconds with all machinery remaining fully operational. Powered by twin Detroit Diesels producing 435 hp (324 kW) each, the 47 MLB can travel at 25 knots (46 km/h) to reach her destination.

There are currently 117 operational with a total of 200 scheduled to be delivered to the USCG. A further 27 models are being built by MetalCraft Marine under license to the Canadian Coast Guard.

In Britain, the RNLI design and build several types of all-weather motor lifeboats, the Arun class kept permanently afloat, the Tyne class slipway-launched boat and the Mersey class carriage-launched boat. More recently the Arun replacement Trent and Severn class prototype models were delivered in 1992 with the first production Trent arriving in 1994 and the Severn in 1996. The first production Tamar class, replacement for the Tyne went into service in December 2005 and the FCB2 class replacement for the Mersey is being developed for deployment in 2007.

In Germany, the DGzRS (Deutsche Gesellschaft zur Rettung Schiffbrüchiger) has provided naval rescue service since 1865. It is a civilian, non-profit organisation and has a wide variety of boats and ships, the biggest being the 46 meter (150 foot) SK Hermann Marwede. The DGzRS operates from 54 stations in the North Sea and the Baltic Sea. It has 20 rescue cruisers (usually piggybaging a smaller rescue boat) and 41 rescue boats.

[edit] References

Early Lifeboats

36 MLB

44 MLB

47 MLB

Coast Guard Agencies

Books

  • John A Culver; The 36 foot Coast Guard motor life boat (1989 J.A. Culver)
  • Bernard C. Webber; Chatham, "The Lifeboatmen" (1985 Lower Cape Pub., ISBN 0-936972-08-4 )
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