The BL 15 inch Mark I was the first British 15 inch (381 mm) gun design and the most widely used and longest lasting of any British designs. The barrel was 42 calibres long (i.e. 15 in x 42 = 630 in) and was referred to as "15 inch/42". The gun fired a 1920 lb (871 kg) shell at a muzzle velocity of 2,575 fps (785 mps). Maximum range in shipboard mountings was 32,500 yards (29,720 m) (30 degrees elevation) but coastal artillery mounting with higher elevations could reach 44,150 yards (40,370 m). Two coastal guns (Clem and Jane) were mounted near Wanstone Farm in Kent in the 1940's. Five guns were mounted in Singapore in the 1930's.