HMS Spearhead was an S class submarine

British S class submarine (1931)

The S-class submarines of the Royal Navy were originally designed and built during the modernisation of the submarine force in the early 1930s to meet the need for smaller boats to patrol the restricted waters of the North Sea and the Mediterranean Sea replacing the British H class submarines...

 of the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

, and part of the Third Group built of that class. She was built by Cammell Laird and launched on July 6, 1944. So far she has been the only ship of the Royal Navy to bear the name Spearhead.

Spearhead survived the Second World War and was sold to the Portuguese in August 1948 and renamed Neptuno.