In 1940, a conspiratorial organisation of sailors was established in Warsaw and Gdynia to conduct anti-German naval intelligence. In 1941, this group found its way to the Commander-in-Chief of the Union for Armed Struggle, General Stefan Rowecki “Grot”. Thanks to this, the armed unit of the Polish Underground State in the General Headquarters launched the Marine Division, code-named ‘Alfa’.

Naval groups initially conspired within the Union for the Reconstruction of the Polish Republic. Their unquestionable leader was Lieutenant Commander Antoni Gniewecki “Witold”. The organisation was concerned with observing the German navy. Information was sent to the ‘base’, which was located in one of Warsaw’s shops at Trzech Krzyży Square. Secret correspondence was transported on ships via river routes.

When, in 1941, the sailors managed to contact the Commander-in-Chief of the then Union for Armed Struggle (later the Home Army), were incorporated into the official structure of the Polish underground. In April 1942, the Naval Division of the Home Army Headquarters with the cryptonym “Alfa”, and later “Oyster”, headed by A. Gniewecki, began to operate. Organisationally, it was subordinated to the Commander of the Western Area of the AK. The tasks of “Alfa” were to conduct continuous naval intelligence and to prepare sailors for actions on the coast and in the ports during the national uprising, and to create naval detachments.

“Alfa” in 1944 comprised 51 officers, 153 non-commissioned officers and sailors, eight civilian employees and 18 women, totalling in 230 employees. The Division was divided into the following departments: organisational and mobilisation, intelligence, and it also had a health department, which oversaw preparing the “Alfa” hospital, collecting medicines.

During the Warsaw Uprising, the Marine Division planned to occupy Czerniakowski Port on the Vistula. To this end, it succeeded in forming a combat unit codenamed “Pike”, commanded by Władysław Macioch “Mizio”. It also included the crew of the workshops of the River Shipyard on the Vistula, which numbered more than 50 people. Also fighting during the uprising was the initiator of “Alfa”- A. Gniewecki. The unit’s task, in addition to capturing the port, was to enable the insurgents to cross the Vistula.

The Polish navy, like the Home Army air force, did not manage to recreate their structures during the occupation. The sailors fought mainly in infantry structures, in intelligence services and in communications.