Dora I & Dora II

Dora I & Dora II
Bomber command had campaigns to attack U-Boat pens on the Atlantic coast . The pens at Trondhiem escaped relatively unscathed .

Suspected Bomb damage on Dora II

Dora I was the only U-Boat pen that was totally completed in Norway and still survives more or less fully intact today . It was used by the Norwegian Armed forces for many years  after the war  but is now, amongst other things, a bowling alley !

Like an Egyptian temple Dora II towers above its surroundings

Dora II was never completed . Raw materials ,such as cement, ran out and the project ground to a halt .Dora II is now used as a dockyard by a number of small companies . Timber shuttering can still be seen in place around access routes into the huge structure .

The fence around is to keep people away because its slowly falling apart .

Dora I , now with a blue building built by the Norwegian navy upon its roof instead of the 3 anti aircraft positions it had during the war.
Dora I was small for a submarine pen hence the commencement of Dora II . The word small though is reletive.
Its HUGE .
 Its 153m long 105m wide and  there is more underground than above ground . Think of an oversized by a half football pitch with concrete poured upto the hight of the tallest of floodlights , thats how huge the building is !

view of the entrance to the pens

Attacks on these two Pens were sporadic and ineffective .  I have found only two reported  major  attacks  .
The first major attack was on the 23rd July 1943 not long after DoraI came into service . Only very light damage was inflicted .
The second  on  either 12th or the  22nd  November 1944 (there are two reports quoting different dates,which both suffered due to lack of visibility) .
One  of these reports quotes bad weather for the aborted attack the other good use of smoke screen due to local experience with having to defend the Tirpitz which was moored near- by  for a while .
Two Lancasters and a Mosquito were lost during these raids with little damage being caused .
It seems that many smaller attacks took place on Trondhiem  , the port facilities and pens but only minor damage was ever inflicted to the pens.

Looking into a pen . the round columns are new and hold up the present day interior to Dora I

A shot of Dora I just after the war 

Kapitans eye view . This is the view any Kapitan leaving the pens would have had from his conning tower 

The building behind is the Dahl brewery ...quite decent beer for Norway

A conning tower from a  Post war Norwegian submarine adorns one of the pens jetties .
Its from HNoMS ULA S300  , a 207  Kobben class submarine that served the Norwegian navy from 1965 to 1990 . In 1987 this boats name was changed from ULA to KINN .
It was one of 15  207 Kobben class submarines commissioned by the Norwegian navy and built in Emden ,Germany .

Blast doors .
The Dora I pen had blast doors 30mm thick to protect it from bombing . In the shot above can be seen a gantry with Blast doors that perhaps covered doors and windows into the bunker .
To the left a shot of a part of one of the blast doors for the pen U-boat entrances  themselves ....now used as a place to mount an info panel .
Leaning against the building can be seen other segments of the huge blast doors .
The roof itself was made from re-enforced concrete 3.8m thick , the walls of the same up to 2.5m thick .
The energy consumption for the Pens was immense ....just imagine how much power would be needed to shut the blast  doors for instance . The ever pragmatic Germans built a power station between Dora I and Dora II which still stands today (see pic below) . No longer a power station it contains a Jujitsu club within its walls ...a different kind of power :-)