Panzerkampfwagen III Ausf H(U) – Tauchfahig (U-Panzer / Submersible Tank)This U-Panzer belonged to the 18th Panzer Division’s 18th Panzer Regiment. This photo was taken during the crossing of the River Bug at Patulin on 22nd June of 1941. During the preparation for invasion of England – Operation Seelöwe (Sealion), Panzer III and Panzer IVwere converted into submersible tanks able to travel on the bottom of body of water at the depths of 6 to 15 meters.
From June to October of 1940, 160 Panzer III Ausf F/G/H and 8 Panzerbefehlswagen III Ausf E along with 42 Panzer IV Ausf Ds were converted into U-Panzers / Tauchpanzers. After extensive tests and modifications U-Panzer were ready for action. Since Operation Sealion was never realized, Tauchpanzer IIIs and IVs were used during Operation Barbarossa (crossing river Bug at Patulin), in service with 3rd (6th Panzer Regiment) and 18th Panzer Division. It was also planned to use U-Panzers in never realized invasion on the island of Malta.
The Tauchpanzer was developed in mid-1940 for the proposed invasion of England (Sea Lion). The Pz Kpfw III were modified and provided with a submersion kit. Air-intakes were fitted with locking covers, and the exhaust was fitted with non-return valves. The cupola, gun mantlet and hull MG were sealed with waterproof fabric covers.
An inflatable rubber tube surrounded the turret ring. While submerged, the tank drew air through a pipe from a float carrying a snorkel device and radio antenna which remained on the surface. A gyro-compass was used for underwater navigation. The Tauchpanzer could operate in depths of up to 15 metres. A vessel with a hinged ramp was used to disembark the Tauchpanzer at a suitable distance from the shore. With the cancellation of ‘Sea Lion’, the Tauchpanzer were no longer required in quite the same form. At Milowitz near Prague, in the spring of 1941, most of the tanks were modified to make them suitable for river crossing, with a fixed snorkel pipe attached through the commander’s cupola.
From July 1940, four sections of volunteers from existing Panzer regiments were trained on the Island of Sylt, and the Tauchpanzer were to be ready for operations at Putlos by 10 August. In mid-October, three of these sections were attached to the 18th Panzer Division, and the remainder went to the 6th Panzer Regiment of the 3rd Panzer Division. On 22 June 1941, the Tauchpanzer of the 18th Panzer Division crossed the River Bug at Patulin.
At Pratulin, where 17th and 18th Panzer Divisions were to cross the Bug, there was no bridge. At 04:15 hours, the advance detachments leaped into their rubber dinghies and assault boats, and swiftly crossed to the other side. The infantrymen and motor-cycle troops had with them light anti-tank guns and heavy machine-guns. The Russian pickets by the river opened up with automatic rifles and light machine-guns. They were quickly silenced.
Units of the motor-cycle battalion dug in. Then everything that could be pumped into the bridgehead was ferried across. The sappers at once got down to building a pontoon bridge.But what would happen if the Russians attacked the bridgehead with armour? How would the Germans oppose them? Tanks and heavy equipment could have been brought across only with the greatest difficulties in barges or over emergency bridges.
That was why an interesting new secret weapon was employed here for the first time….…In the sector of 18th Panzer Division fifty batteries of all calibers opened fire at 0315 in order to clear the way to the other bank for the diving tanks, General Nehring, the divisional commander, has since described this as “a magnificent spectacle, but rather pointless since the Russians had been clever enough to withdraw their troops from the border area, leaving behind only weak frontier detachments, which subsequently fought very bravely.”
At 0445 hours Sergeant Wierschin advance into the Bug with diving tank No.1. The infantrymen watched him in amazement. The water closed over the tank. ”Playing at U-boats!” Only the slim steel tube which supplied fresh air to the crews and engine showed above the surface, indicating Wierschin’s progress under water. There were also the exhaust bubbles, but these were quickly obliterated by the current.
Tank after tank – the whole of 1st Battalion, 18th Panzer Regiment, under the battalion commander, Manfred Graf Strachwitz – dived into the river.
And now the first ones were crawling up the far bank like mysterious amphibians. A soft plop and the rubber caps were blown off the gun muzzles. The gun-loaders let the air our of the bicycle inner tubes round the turrets. Turret hatches were flung open and the skippers wriggled out. An arm thrust into the air three times: the signal “Tanks forward.”Eighty tanks had crossed the frontier river under water. Eighty tanks were moving into action.
Their presence was more than welcome in the bridgehead. Enemy armoured scout cars were approaching. At once came the firing orders for the leading tanks: “Turret – One O’clock – armour piercing – 800 yards – group of armoured scout cars – fire at will.” From Hitler Moves East–Paul Carell.
During September and October 1940 volunteers of the 2nd Tank Regiment in Putlos were formed into Tank Battalion A and trained for Operation Sea Lion, the invasion of Great Britain. Two other special formations, Tank Battalions Band C, were being raised at the same time and the same place. These units later formed the 18th Tank Regiment of the 18th Panzer Division and adapted the Pz Kpfw III and IV for submerged wading. The following measures were taken. All openings, vision slits, flaps, etc, were made watertight with sealing compounds and cable tar, the turret entry ports were bolted from the inside and air intake openings for the engine completely closed.
A rubber cover sheet was fixed over the mantlet, the commander’s cupola and the bow machine gun. An ignition wire blew off the covering sheet upon surfacing and left the vehicle ready for action. Between the hull and the turret there was a rubber sealing ring which, when inflated, prevented the water from entering. The fresh air supply was maintained by a wire-bound rubber trunk with a diameter at about 20 cm, 18 metres long. To one end of this tube was fitted a buoy with attached antennae. The exhaust pipes were fitted with high-pressure non-return relief valves. When travelling submerged sea water was used to cool the engine and seepage was removed by a bilge pump. The maximum diving depth was 15 metres. Three metres of the air tube’s 18 metre length was available as a safety measure.
These submersible tanks were to be launched from barges or lighters. They slid into the water down an elongated ramp made of channel plates. Directing was achieved by radio orders from a command vessel to the submerged vehicle. Underwater navigation was carried out by means of a gyro compass and the crew was equipped with escape apparatus. The submerged machines were relatively easy to steer as buoyancy lightened them. After Operation Sea Lion was abandoned these vehicles were eventually used operationally during the Russian campaign in 1941 for the crossing of the River Bug.
A short intelligence report on German tanks modified for submersion, from Tactical and Technical Trends, July 29, 1943.