HDMS Dykkeren was the first Danish submarine built by FIAT San Giorgio for the Royal Danish Navy and commissioned in 1909.

[1] In 1910, Dykkeren was equipped with radiotelegraphy equipment, thereby becoming one of the first submarines in the world to have this.

[2] In 1916, Dykkeren collided with a ship, causing the submarine to sink, everyone apart from the chief, First Lieutenant Christensen, is saved.

[3]