HMS Cassandra was a C-class

C class cruiser

The C class was a group of twenty-eight light cruisers of the Royal Navy, and were built in a sequence of seven classes known as the Caroline , Calliope , Cambrian , Centaur , Caledon , Ceres and Carlisle classes...

 light cruiser

Light cruiser

A light cruiser is a type of small- or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck...

 of the British 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...

. She was part of the Caledon group of the C-class of cruisers.

She was built by Vickers Limited

Vickers Limited

Vickers Limited was a famous British engineering conglomerate that merged into Vickers-Armstrongs in 1927.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...

, Barrow in Furness and laid down in March 1916, launched on 25 November 1916 and commissioned into the Navy in June 1917.

She had a short career, and initially joined the 6th Light Cruiser Squadron of the Grand Fleet. She suffered a mishap when she ran aground on Fair Isle

Fair Isle

Fair Isle is an island in northern Scotland, lying around halfway between mainland Shetland and the Orkney islands. It is famous for its bird observatory and a traditional style of knitting.-Geography:...

 on 15 August 1917 but was successfully salvaged. Despite this she survived the war, and was sent into the Baltic

Baltic Sea

The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...

 to operate against the Bolsheviks. On 5 December 1918 she ran into an uncharted German minefield. She struck a mine

Naval mine

A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...

 and sank in Gulf of Finland

Gulf of Finland

The Gulf of Finland is the easternmost arm of the Baltic Sea. It extends between Finland and Estonia all the way to Saint Petersburg in Russia, where the river Neva drains into it. Other major cities around the gulf include Helsinki and Tallinn...

 with the loss of 10 sailors but the remaining crew of 400 was evacuated.

Rediscovery

The Estonian Navy

Estonian Navy

The Merevägi is the navy of Republic of Estonia and is part of the unified Kaitsevägi .In total, there are about four commissioned ships in the Estonian Navy, including three auxiliary ships; the displacement of the navy is under 10,000 tonnes making it one of the smallest navies in the world...

 and Estonian Maritime Museum announced in August 2010 that they had located the wrecks of HMS Cassandra, and two Flower-class

Flower class sloop

The Flower class comprised five sub-classes of sloops built under the Emergency War Programme for the Royal Navy during World War I, all of which were named after various flowers...

 sloops

Sloop-of-war

In the 18th and most of the 19th centuries, a sloop-of-war was a warship with a single gun deck that carried up to eighteen guns. As the rating system covered all vessels with 20 guns and above, this meant that the term sloop-of-war actually encompassed all the unrated combat vessels including the...

  and near Saaremaa Island in depths of 60-100 metres.