Cachalot-class submarine
 The Cachalot-class submarines were a pair of medium-sized submarines of the United States Navy built under the tonnage limits of the London Naval Treaty of 1930. They were originally named V-8 and V-9 and so were known as V-boats even though they were unrelated to the other seven submarines (V-1 through V-7) constructed between World War I and World War II. Joseph W.