The first expedition

Departure was at 06:00 hours the 7^th of April 1940 from Swinemünde in northern Germany with a course set for Oslo. On board were 2202 men, 822 of which were in addition to the crew.  These included Generalmajor Engelbrecht, parts of group XXI, parts of the 163rd infantry division, staff and music corps from infantry regiments 307, sevral battalions of infantry regiments 307 and 163, mail personnel, radio technicians, war reporters and the propaganda company.

The battles commence

On April 8th 23:30 hours the ships had reached the area around Færder in the outer Oslo fjord and 23:55 hours were discovered there by the small Norwegian patrol vessel Pol III. The man in charge of the Norwegian guard boat, Captain Leif Welding Olsen, immediately went on the attack, and, with the help of signal flares, warned the forts of Rauøy and Bolærne.

Fort Bolærne had not seen the signal from Pol III and the German torpedo boat Albatross, and as a result the fort did not open fire. At Fort Rauøy the signal lights were seen and the crew were manning the cannons.

There was a short and dramatic exchange of fire between Pol III and the German torpedo boat Albatros, which later the same day sank herself by running aground at the southern tip of Isla South-søster in Hvaler. Captain Leif Welding Olsen on the Pol III was mortally wounded and died at sea when Pol III at 00:45 hour capsize and sank. 14 menn from the crew of 17 was prison taken. Leif Welding Olsen was the first Norwegian who died in battle with the Germans.

The German fleet continued North at 12 knots toward the Outer Oslo fjord Fortress. This fortress consisted of four forts, but only three of them were manned and no minefields had been lain. Måkerøy, Bolærne and Rauøy were the manned forts. The German ships were observed by Måkerøy and Bolærne, but the watchmen at Rauøy saw them a little sooner.  Because of the fog and the darkness of the night they had trouble identifying the ships' nationality. But after a slight hesitation the chief of Rauøyfort gave the order to fire. Visibility was bad and the fort's searchlights were ineffective in the fog. One could just glimpse the two foremost ships, however, and two warning shots were fired; first a load with blank ammunition, and then one with live fire. The vessels gave no sign of stopping, and four more shots were fired from Rauøy's 15 cm cannons. None of the shots connected. The Germans did not return fire, and visibility was so bad that the north-bearing ships could no longer be seen from the fort. The firing ceased and the ships had passed by. Later that night, the Germans went ashore at Rauøy which attempted to defend itself in vain.

The morning of the 9th of April 1940, the Norwegian fort commander received orders to cease firing. Reluctantly, the commander obeyed and Rauøy was thereby under German control. Måkerøy and Bolærne were not involved in the firefight that night. The Germans had penetrated the outer Oslo fjord without significant problems. But it wouldn't be so easy later that morning when they attempted to pass the Drøbak channel where the Oslo fjord's inner fortresses lay.

Around three in the morning, German warships were observed outside Filtvedt in Hurumlandet peninsula. There were three large ships and a number of smaller ones sailing north. A half hour later the same ships were observed by Norwegian watch vessels sent from Oscarsborg fortress, which had been alerted in the Drøbak channel. The warships sailed toward the Oscarsborg fortress. Blücher's top speed of 32.5 knots was one of the strengths of what was meant to be a surprise attack, and therefore did not have any smaller ships ahead of it as it normally would in this type of situation. Blücher was at the head of the squadron in the fjord.

Moses... the cannon !

Oscarsborg Fortress was very well situated, but outfitted with very out-of-date equipment. Most of the crew on duty had received almost no training and there were far too few of them. The commander of the fortress, Colonel Birger Eriksen, was faced with great difficulties. The Drøbak channel had not been laid with mines either.  The fortresses biggest battery had been placed at Søndre Kaholmen (the southern islet). The largest weapons were two old 28cm Krupp cannons from 1892. The first of these was popularly known by the nickname "Moses".   It got this name after it fell in the water while it was being unloaded for installation in 1892 and was raised back up from the sea. Its twin cannon was, naturally enough, called "Aron". In their time they had been the Norwegian defense's proudest new recruits, but were now quite antiquated. On the northern islet stood a torpedo battery under the command of Commander Captain Anderssen, and on the Drøbak side two smaller cannon batteries were placed on Husvik.