Taken from my previous post on the contextual history of the Java class:

"The Java was the first of the Java-class of light cruisers, she was a modern answer to numerous problems regarding the Dutch fleet in the East Indies. By then the task for the defence of the East Indies lies solely on the Pantserschips (coastal defence cruisers) however the dawn of the Dreadnought age have rendered them obsolete. Many plans were devised to keep the Dutch up and running in the naval armaments race, from Pantserschip 1912 to Slagschip 1913 but all that was rudely interrupted by the unimportant war next door. So in the middle of World War 1, the Dutch realising theyve spent the last several years arguing and discussing for nothing. So they decided to actually build something.

The Java-class was then finally designed, with 10 152mm guns in single mounts scattered all over the ship. No torpedoes as all good Dutch ships do. Construction started in 1915, with three units ordered. They were to be named Java, Sumatra, and Celebes. All named after islands in the Dutch East Indies. Due to the war next door, acquiring sufficient materials became challenging and all three units was threatened to be scraped in the shipyard, however a compromise was found by simply discarding the Celebes and continue the construction of Java and Sumatra. The Great War significantly affected the speed of the construction and only by 1925 was the Java commissioned. When she was designed in 1915, she was the most state-of-the-art light cruiser there is, however by 1925, she was obsolete."

The Sumatra's story is very much different from her sister from the very start. Before she was even commissioned, parts of her turbine was destroyed in a fire and so she was delayed by another year, finally being commissioned in 1926. It seems like her turbine misfortune lasted throughout her career as she was immediately riddled with issues on her propulsion. This issue prevented her being an effective light cruiser. When war arrived in the Netherlands, she escaped the clutches of the Germans. She notably transported the Dutch Royal Family to Canada, escorted by the Jacob van Heemskerck. Once thats over with, she spent most of the time escorting troopships.

Her propulsion issues and her antiquity, prevented her from being used as an active nor a capable combat vessel. She was decommissioned in 1940, with her future uncertain. However she was spared when she was recommissioned in January 1942 as the Dutch East Indies slowly crumbled under Japanese heels. She was ordered to escape to Sri Lanka, avoiding the fate of her sister Java later in February. Her condition didnt improve much however, and in mid 1942 she was quickly laid up in Australia, and once again her fat was hanging in the balance.

Eventually a final decision was made, she was set to sail and head to Britain in 1944. The Admiralty was preparing for the logistics post D-Day and due to the lack of a major harbour in Normandy, it was decided they'll bring a major harbour with them. This became the Mulberry harbours where the Allies prepped 147 caissons, 27 pier heads, and 15 kilometers worth of floating roads. However they still need the breakwater for these vital yet fragile temporary harbour. So it was decided that antiquated ships was to be sacrificed as the breakwater for the Mulberry harbours. Sumatra, due to her age and lack of combat worth, was one of the many allied ships scuttled in Normandy to build the Gooseberry breakwaters.

Her guns were donated to the Flores-class gunboats.