52-foot Motor Lifeboat

The United States Coast Guard operates four 52-foot Motor Lifeboats (MLBs), which supplement its fleet of 227 47-foot Motor Lifeboats. These vessels were built in the late 1950s and early 1960s, and displace 32 tons. The four vessels are all stationed in the Pacific Northwest. The vessels are remembered for the many lives they saved over 60 years of service in brutal ocean conditions of the Pacific Northwest.

By the 2020s the brunt of rescue activities has been taken over by the 47 footers, while the four vessels fate is pending.

Design and history
After World War II, reduced budgets meant the Coast Guard continued to use its two existing wooden 52' MLBs, also known as the Type F lifeboats, Invincible and Triumph. By the late 1950s, the wooden MLBs were starting to wear out and the Coast Guard built a set of steel 52' MLBs at Curtis Bay Yard to replace them, specifically designed for the high surf conditions encountered along the Pacific Northwest coast. The steel 52' MLBs feature an aluminum superstructure and a hull divided into seven watertight compartments; because of their relatively high cost of US$250000 1956 each, only four were built. After entering service, the steering/rudder system was modified by removing the rudder guard, shortening the bilge keels, installing twin rudders, and adding a hydraulic power assist to the steering.

The Coast Guard bills the 52-foot MLBs as "virtually unsinkable", with self-righting and self-bailing capabilities and the ability to tow vessels as large as 750 LT in 30 ft seas. In comparison, the next-largest 47' MLB has a towing capacity of 150 LT. To increase their endurance and capabilities, the 52' MLB is equipped with a complete galley and a fire/salvage pump with 250 gal/min capacity.

In the 21st century, the Korean-war era vessels had to use custom built parts to stay operational.

On October 1, 2020, the fleet was placed on restricted status due to maintenance and safety concerns. In November 2021, all 4 boats were towed to Coast Guard Station Cape Disappointment and laid-up pending a decision on their future disposition.

As of 2022, without a clear successor, main rescue activities were taken on by the 47 foot rescue boats pending a decisions about the 52 foot boats.

Vessels
The 52' MLBs are the only vessels of the Coast Guard less than 65 ft in length to receive names, keeping with the tradition established by their wooden predecessors.


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