The Hydra class were two minelayer

Minelayer

Minelaying is the act of deploying explosive mines. Historically this has been carried out by ships, submarines and aircraft. Additionally, since World War I the term minelayer refers specifically to a naval ship used for deploying naval mines...

s of the Royal Netherlands Navy

Royal Netherlands Navy

The Koninklijke Marine is the navy of the Netherlands. In the mid-17th century the Dutch Navy was the most powerful navy in the world and it played an active role in the wars of the Dutch Republic and later those of the Batavian Republic and the Kingdom of the Netherlands...

, built to serve in the Dutch East Indies

Dutch East Indies

The Dutch East Indies was a Dutch colony that became modern Indonesia following World War II. It was formed from the nationalised colonies of the Dutch East India Company, which came under the administration of the Netherlands government in 1800....

 and Dutch territorial waters in Europe. The construction of the ships began in 1910 and was completed in 1912. The ships were built by the navy yard (Rijkswerf) in Amsterdam

Amsterdam

Amsterdam is the largest city and the capital of the Netherlands. The current position of Amsterdam as capital city of the Kingdom of the Netherlands is governed by the constitution of August 24, 1815 and its successors. Amsterdam has a population of 783,364 within city limits, an urban population...

. Both ships were still in service during the Second World War

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. Only the Medusa escaped to the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, however. The Hydra was lost after it was fired on by an anti-tank weapon. It sank in the waters off Zeeland

Zeeland

Zeeland , also called Zealand in English, is the westernmost province of the Netherlands. The province, located in the south-west of the country, consists of a number of islands and a strip bordering Belgium. Its capital is Middelburg. With a population of about 380,000, its area is about...

.

Ships in class

• Hr. Ms. Hydra (1912–1940)
• Hr. Ms. Medusa
  HNLMS Medusa (1911)
  HNLMS Medusa was a Dutch minelayer of the Hydra class, built in Amsterdam and named after Medusa in Greek mythology.-Service:...
  
  (1911–1964)

Source

• netherlandsnavy.nl : Hydra-class minelayers