World War II affected every corner of America and the small towns of the Cape were no exception. In 1941, with the completion of Camp Edwards on the Upper Cape, Cape Cod was thrust head first into the war effort. The town of Falmouth’s streets and businesses were overflowing with soldiers and its beaches and coastal waters were dotted with amphibious craft and Navy convoys.
Founded in 1930, the Woods Hole Oceanographic Institution (WHOI) was mostly a summer research facility. In 1940, WHOI director Columbus Iselin wrote to the National Defense Research Committee outlining ways that the study of oceanography could benefit the military’s efforts. The U.S. knew that German oceanographers had already spent the past five years mapping the world’s oceans, so in July 1940 WHOI’s first official Navy contract was under way.
A collaboration between WHOI and the Navy took over Great Harbor in Woods Hole in 1941. WHOI’s scientists and staff tackled a wide range of projects for the Navy, including the development of underwater explosives, the use of smokescreens in Naval warfare, the improvement of antifouling paints for the bottoms of ships, underwater photography and the development of better sonar and echo technology.
Arguably, WHOI’s most significant contribution to the war effort was the development of the bathythermograph or BT Device, which proved essential in the United States’ fight against the masterful and mysterious German submarines. Despite the emerging use of sonar on ships, the U.S. Navy had virtually no idea where the U-boats were or when they would strike. A tool was needed that could locate the German submarines. Enter the BT device.
The ocean is stratified into layers of varying densities and temperatures. Sonar travels through ocean water at different speeds depending on the temperature and density of the water. When the sun warms the surface of the ocean, a layer called a thermocline develops deeper in the water and is defined by a sharp decrease in temperature. Almost like a force field, it bends and reflects sonar waves. It was the perfect hiding spot, and it turns out, it was often where German subs would hide.
Athelstan Spillhaus developed the device in 1937 and its function was perfected by Allyn Vine, Maurice Ewing and Joe Worzel—all WHOI scientists. The BT device measures both the depth and temperature of the water. With that new information, scientists could determine where the thermocline layers occurred and account for speed changes in sonar waves. The breakthrough made the sonar readings more accurate.
The WHOI scientists trained many Navy men in the use of the BT Device. Successful campaigns against the German U-boats soon followed. In 1939, Germany lost just under 10 U-boats the entire year. By 1943, that number had jumped to over 200. U.S. submarines also used the BT Device. They used it to find their own hiding spots.
The Navy decommissioned its Woods Hole base in 1943. WHOI continued its work for the Navy and the government well into the mid-20th century. That guaranteed source of work and funding was one of the driving forces of the institution’s early success and growth.
World War II left an important legacy here on Cape Cod. Many beaches and conservation areas: Sandy Neck, the Cape Cod National Seashore, Washburn’s Island, South Cape Beach—exist as they are because of the United States military. After the war ended, the military no longer needed the coastal land for training and transferred those properties to the state and subsequently, they became state parks. If you look at a recent map showing land use on Cape Cod, the only pristine areas left are these same beaches where amphibious crafts once practiced their maneuvers.
DID YOU KNOW?
Many people today are unaware of the role that Cape Cod played in World War II.
The famous DUKW boats were tested on Cape Cod’s beaches.
Camp Edwards was the first division-sized base built by the U.S. Army. It only took 125 days to build enough infrastructure for close to 30,000 soldiers. The design became a template followed by subsequent bases around the country.
The Engineer Amphibian Command (EAC) was established at Camp Edwards in June 1942. They trained on beaches from Falmouth to Wellfleet. Locals renamed them the “Cape Cod Commandos.” These water-to-land units were essential to invasions (North Africa, Sicily, Normandy, Philippines and Okinawa, to name a few) in both Pacific and Atlantic theaters.
In September 1942, there was a mock invasion of Martha’s Vineyard in preparation for the assault on North Africa.
At its peak training capacity in 1943, there were roughly 68,000 soldiers stationed at Camp Edwards. The civilian population of Cape Cod was just under 30,000 at that time.