A submarine snorkel is also a device that allows a
submarine to operate submerged while still taking in air from above the
surface. It was invented by the Dutch just before
World War II and perfected by the Germans during the war for use by
U-boats. Its common military name is
snort.
Until the advent of nuclear power, submarines were designed to operate on the surface most of the time and submerge only for evasion or for rare daylight attacks. In
1940, at night, a U-boat was safer on the surface than submerged because
ASDIC could detect boats underwater but was almost useless against a surface vessel. However, with the continued improvement in methods of detection and attack, as the war progressed, the U-boat was forced to spend more and more time underwater running on electric motors that gave speeds of only a few knots and with very limited endurance.
The
1940 defeat of the
Netherlands by the
Wehrmacht was a stroke of luck for the
Kriegsmarine. The Dutch had been working on a device that the Germans called the
Schnorchel. The Dutch navy had been experimenting as early as
1938 with a simple pipe system on the submarines
O-19 and
O-20 that enabled them to travel at periscope depth operating on its diesels with almost unlimited underwater range while charging the propulsion batteries.
The
Kriegsmarine, at first, gave some consideration to the snorkel as a means to take fresh air into the boats but saw no need to run the diesel engines underwater. In
1943, however, as more U-boats were lost, it was retrofitted to the
VIIC and
IXC classes and designed into the new
XXI and
XXIII types.
The first boat to be fitted with a snorkel was
U-58 which experimented with the equipment in the Baltic during the summer of
1943. Boats began to use it operationally in early
1944 and by June
1944 about half of the boats stationed in the French bases had snorkels fitted.
On
Type VII boats the snorkel folded forward and was stored in a recess on the port side of the hull while on the
IX Types the recess was on the starboard side. The
XXI and
XXIII types both had telescopic masts that rose vertically through the conning tower close to the periscope.
Snorkels created several problems for their users. A U-boat with a snorkel raised was limited to six knots to avoid breaking the tube and its sound detection gear was deafened by the roaring of the air being sucked down the tube. A submarine that stayed underwater for more than a few hours encountered various disposal problems and had to store garbage internally, further fouling boats already infamous for their odors.
Most dramatically, snorkels were equipped with automatic valves to prevent seawater from being sucked into the diesels, but when these valves slammed shut the engines would draw air from the boat itself before shutting down, which was extremely painful to the ears of the crew and sometimes even ruptured eardrums. This last problem still exists in modern submarines, though their larger internal air volume mitigates the pain somewhat.
Ouch lol and IIRC the British had access to the snort when Dutch uboats sailed to England to avoid being caught in port in 1940 but the British decided they were too dangerous to use and took them off the Dutch boats
REAL early schnorkel use
http://uboat.net/articles/index.html?article=63