The Action in the Oslofjord occurred late on 8 April 1940 in World War II. As ''

Kampfgruppe In military history, the German term (pl. ; abbrev. KG, or KGr in usage during World War II, literally "fighting group" or " battlegroup") can refer to a combat formation of any kind, but most usually to that employed by the of Nazi Germa ...

'' 5 of the German invasion force proceeded towards

Oslo Oslo ( or ; ) is the capital and most populous city of Norway. It constitutes both a county and a municipality. The municipality of Oslo had a population of in 2022, while the city's greater urban area had a population of 1,064,235 in 2022 ...

, it encountered Norwegian defences in the

Oslofjord The Oslofjord (, ; ) is an inlet in southeastern Norway. The fjord begins at the small village of Bonn in Frogn, Frogn Municipality and stretching northwards to the city of Oslo, and then curving to the east and then south again. It then flows s ...

. During a short exchange that resulted in the first Norwegian casualty of the war, the Germans managed to push through down to Drøbak Sound, where they would face more determined resistance.

Prelude

In order to invade

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

, the Germans divided their naval forces into six groups. The fifth of these, "''

'' 5," was to pass through the

and land troops in

. The group consisted of the

heavy cruiser A heavy cruiser was a type of cruiser, a naval warship designed for long range and high speed, armed generally with naval guns of roughly 203 mm (8 inches) in calibre, whose design parameters were dictated by the Washington Naval Treat ...

s and ''Lützow'', the

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. Prior to thi ...

, the

torpedo boat A torpedo boat is a relatively small and fast naval ship designed to carry torpedoes into battle. The first designs were steam-powered craft dedicated to ramming enemy ships with explosive spar torpedoes. Later evolutions launched variants of ...

s , and and eight

minesweeper A minesweeper is a small warship designed to remove or detonate naval mines. Using various mechanisms intended to counter the threat posed by naval mines, minesweepers keep waterways clear for safe shipping. History The earliest known usage of ...

s. The ships were under orders not to open fire unless fired upon. The outer parts of the fjord were guarded by the Oslofjord Fortress, established in 1914, made up of smaller forts at Bolærne and Rauøy. Of the 11 guard ships operating out of

Tønsberg Tønsberg (), historically Tunsberg, is a List of towns and cities in Norway, city in Tønsberg Municipality in Vestfold county, Norway. It is located about south-southwest of the capital city of Oslo on the western coast of the Oslofjord near ...

, would be tasked with patrolling the

on the night of 8 April. Requisitioned by the

Norwegian Navy The Royal Norwegian Navy () is the branch of the Norwegian Armed Forces responsible for naval operations of Norway, including those of the Norwegian Coast Guard. , the Royal Norwegian Navy consists of approximately 3,700 personnel (9,450 in mob ...

in 1939, ''Pol III'' was armed with a gun and two machine guns. The ship had a crew of 15, including its commander Captain Leif Welding-Olsen.

Action

Shortly after 23:00 on 8 April, Lieutenant Hans Bergan of ''Pol III'' spotted the anonymous invasion force at the mouth of the

. The patrol boat fired a warning shot, and closed with the German torpedo boat ''Albatros''. Admiral Oskar Kummetz, having seen the patrol boat to his ships' port sides, ordered ''Albatros'' to intercept it. Captain Leif Welding-Olsen of ''Pol III'' had a short conversation with the commander of the German boat, ''Kapitanleutnänt'' Siegfried Strelow, who demanded his surrender, to which he refused. Realizing that Norwegian neutrality was going to be violated, Olsen radioed a warning to Horten Naval Base: "Alien ships incoming at high speed,"Pearson, Robert
Gold Run: The Rescue of Norway's Gold Bullion from the Nazis, 1940
p. 22 fired flares for their

coastal artillery Coastal artillery is the branch of the armed forces concerned with operating anti-ship artillery or fixed gun batteries in coastal fortifications. From the Middle Ages until World War II, coastal artillery and naval artillery in the form of ...

(one white, two red,Forsvarets museer
Da Pol III møtte overmakten 8.april 1940
(in Norwegian) meaning ''"Enemy ships are forcing the line."''), then ordered ''Pol III'' to ram ''Albatros''. Having just been rammed and seeing the guns manned on the patrol boat, Strelow ordered his ship's anti-aircraft batteries to open fire on the Norwegian ship. Captain Olsen was struck in the leg by machine gun fire and the ship was set ablaze. The order was given to abandon ship. The lifeboat was lowered into the water but overturned, so the crew was forced to cling to its sides. Weakened by blood loss, Olsen let go and drowned, becoming the first Norwegian casualty of the war. The surviving 14 crew were picked up by the invasion force and held captive. At 23:30, ''Kampfgruppe'' 5 was spotted by Rauøy fort's searchlight. The southern battery of the fort fired two warning shots. At 23:32, Bolærne fort fired a single warning shot. At 23:35, Rauøy fort targeted the cruiser ''Blücher'' and fired four live rounds, but missed due to poor visibility. Shortly thereafter the ships disappeared from view in the mist, and contact was lost.

Aftermath

The Germans proceeded down the

fjord In physical geography, a fjord (also spelled fiord in New Zealand English; ) is a long, narrow sea inlet with steep sides or cliffs, created by a glacier. Fjords exist on the coasts of Antarctica, the Arctic, and surrounding landmasses of the n ...

towards Oslo. Rauøy forwarded Captain Oslen's original warning down to Oscarsborg Fortress, which was able to halt the Germans in the

Battle of Drøbak Sound The Battle of Drøbak Sound took place in Drøbak Sound, the northernmost part of the outer Oslofjord in southern Norway, on 9 April 1940. It marked the end of the "Phoney War" and the beginning of World War II in Western Front of World War II, ...

, sinking ''Blücher'' and severely damaging ''Lützow''. Minesweepers and two torpedo boats detached from the main force would land troops in the area the next morning, and the Norwegians would withdraw from their forts over the next few days. Torpedo boat ''Albatros'' ran on shore and sank on 10 April west of Fredrikstad. Following Oscarsborg's capitulation, the remainder of ''Kampfgruppe'' 5 would land in Oslo on 10 April. After signing an oath of non-belligerence, the captive Norwegians were released and allowed to return home. HNoMS ''Pol III'' was left burning and adrift overnight. It rained and the fire burnt out on its own. The next morning the ship was discovered by the Norwegian patrol boat ''Skudd 2'', and towed to

, where it would be captured by the Germans.''D/S Pol III'' (Norwegian Homefleet - WW II)
/ref>

References

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1940 in Norway 1940s in Oslo Norwegian campaign April 1940 in Europe