[FEATURE ARTICLE] World War I Splinter Fleet: The Sub Chasers that Challenged the U-Boat Menace

Over the past months, we’ve shared stories about the impact of World War I on the Ocean State. This time, here’s a look at one of the unsung heroes of the war: the SC-1 sub chasers, affectionately known as “The Splinter Fleet.” On July 20, 1917, the U.S. Navy set up operations on Block Island, RI. The role of the base was to support coastal anti-submarine patrols. Among the small craft stationed there during the war were a number of these sturdy little wooden warships. Along with the small sisters, known as patrol craft, the sub chasers moored at Hog Basin or Payne’s Dock, from whence they patrolled nearby waters. After the war, one of them even became the popular, long-serving Block Island ferry Elizabeth Ann.

The majority of sub chasers patrolled along the Atlantic coast while 121 boats were sent overseas to battle the German U-boat threat around Great Britain and in the Mediterranean. They gained fame during one of the best-known Mediterranean campaigns, the Otranto Barrage (actually an anti-submarine net barrier) in the summer of 1918 in the Adriatic. Nearly one quarter of the total number on sub chasers built were sold to the French.

The winds of war were blowing ever closer to America in 1916, even more so later that year when a large German merchant submarine twice escaped the British blockade, reaching the United States and returning home with valuable cargo. On October 8, 1916, the German U-53 paid a surprise visit to Newport and gave the U.S. Navy a close-up look at its sophisticated construction and capability. The day after its 5-hour visit, U-53 skipper Klt. Hans Rose sank five ships off Martha’s Vineyard. Clearly, there was a need for a response to the growing U-boat menace that could easily reach close to home.

That same year, then Assistant Secretary of the Navy Franklin D. Roosevelt, looking ahead to America’s likely involvement in the war, ordered the design of a small anti-submarine vessel that could be quickly built in large numbers and without the use of steel (needed for larger, more powerful surface warships). Naval architect Albert Loring Swasey is credited with the initial design for the sub chaser. The result was a rugged little war boat somewhat modeled after popular motor yachts of the day, with a little influence from British patrol boats already in use overseas.

A total of 441 sub chasers were built between 1917 and 1919. Government Navy yards and large private ship builders were committed to building destroyers and larger surface craft, so the Navy turned to small private shipyards up and down the Atlantic and Pacific coasts and a few on inland waterways to turn out the sub chasers (a number were also constructed at several Navy yards). But all followed a standard pattern.

The result was a shallow draft 110-foot, 85-ton wooden craft lightly armed with a single 3″/23 caliber gun forward, a pair of .30 caliber machine guns, and a single Y-gun depth charge projector. The boats were powered by three 220hp gasoline engines, with triple screws, capable of driving them at a maximum speed of 18 knots with a range of about 1,000 nautical miles. Most were equipped with a primitive hydrophone listening device. Two officers and 25 enlisted men made up the crew. Officers were reservists, often newly commissioned and drawn from the ranks of recreational yachtsmen experienced in handling small boats.

Sub chasers managed to make it across the Atlantic under their own power, helping to escort convoys along with larger warships and refueling from tankers along the way. It was, to say the least, a far from comfortable journey for these little ships with their constant rolling and pitching.

Along the way, sub chaser crews had to deal with leaks and flooded engine rooms sustained in turbulent seas. Refueling at sea from convoy tankers, they managed to make it across. The U.S. Navy’s principal European base in World War I was Queensland (now Cobh) in Ireland. Sub chasers fanned out from there to other postings. Duty on the chasers was tough. One crewman, Radioman Cary Johnston on SC-129, said, “after a few weeks of bully beef and hardtack, the very thought of the next meal turned one’s stomach … then there was the continuous heaving and rolling of the ship. Even a light breeze tossed us about. But, if that wasn’t enough, the windblown ocean salt spray, combined with the engine exhaust gasses … kept the crew in a constant state of nausea.” But, other than that, it wasn’t bad duty.

Working on both sides of the Atlantic and in the Mediterranean, sub chasers conducted anti-submarine patrols, escorted convoys, and engaged in mine sweeping activities, blockades, and net tending. How successful were they? Naval historians continue to debate this question. Some credit them with a kill rate of as many as 40% of total U-boat sunk. Others deny them a single victory over the enemy. But, all are agree that, given their size, numbers and courage of their crews, they proved to be a deterring factor against enemy submarines. In the Adriatic in 1918, for example, they participated in blockades and mine clearing activities that contributed significantly in proportion to their size and numbers. Sub chasers usually operated in units of three boats.

Remarkably, only a half-dozen American sub chasers were lost during the war (and three by France), none to direct enemy action. After the Armistice, many were sold off to foreign governments or private owners. A few were transferred to the Coast Guard where they saw service against the rumrunner fleet during Prohibition (although the bootleggers, taking a lesson from the War, equipped their boats with more powerful converted Liberty aircraft engines).

Overall, sub chasers proved so effective that an updated version was put into service in World War II. These next-generation boats were similar in appearance to their predecessors but were slightly larger and were powered by twin General Motors 8- or 16- cylinder diesels. They were more heavily armed, carrying either a 40mm Bofors or 3″/50 cannon forward, a single 20mm Oerlikon (many of which were built in Rhode Island) amidship, 2 K-gun depth charge launchers, and a pair of mousetrap forward projectile launchers (especially effective against enemy submarines). No sub chasers were built in Rhode Island during World War I; however, of the 438 World War II sub chasers that saw service, a number were built locally: 9 at the Harris and Parsons Shipyard in East Greenwich, RI, 16 at Perkins and Vaughan in Wickford, RI, and two by the Herreshoff’s Manufacturing in Bristol, RI. Several World War II sub chasers were converted for use as landing control vessels to support various invasions during World War II, although none were used on D-Day. Many that survived the war were purchased for private use, much as their older sisters were after World War I.

Sub chasers, while in service for only a relatively short time in World War I, made a tangible contribution to the Allied victory. They even sailed as far north as Archangel, Russia, inside the Arctic Circle. Today, only a handful of sub chaser hulls remain afloat, and all of these are of World War II vintage.