Terje Langoy wrote:.
Now this is not particularly related to the photo in question though I must admit her history point towards a few places of some interest (Gotenhafen and Brest) with regards to the mole seen in the background at this photo. As far as your estimates of this photo goes (length and height of the object) a few thoughts has surfaced. My knowledge of naval architecture is indeed a modest one but I believe we may have a stability issue here to consider as well. If we take the raised tube to be a conning tower then I´d suspect it would be a pretty unstable vessel once manned. With such a sleek hull it would be rolling terribly in the seas and this even worse if you add the weight of a man at its highest point. It is indeed an intriguing photo. I will try to dig up some info on the submarines of the smaller navies, as you suggested.
Thanks for the inputs, Hammy. It is very much appreciated.
It's a pleasure old boy , really .
As regards stability in submarines , you are actually dealing with the most stable and sea-worthy ship on the oceans when looking at diesel/electric submarines . This is because the lower part of the hull contains the batteries , which are extremely heavy , and the fresh water tank , various other tanks to do with trimming the boat fore and aft ( so she is neither nose heavy nor tail heavy ) compensating tanks ( which you flood to make up for the weight of the torpedo you fired , otherwise the boat would lose weight and therefore gain bouyancy ) , and there are also tanks for fuel and sewage down there , the magazine for the guns ammo , the hold for supplies and stores , and all kinds of other heavy stuff like pumps and ranks of big compressed air bottles.
All that has a deck laid over it , and that is what all the crew is standing on , when you see the inside of a sub in the films .
That makes a D/E sub very " STIFF " which is a technical term meaning a ship with a low centre of gravity . Such a ship will roll easily and quickly , possibly as far as 90degrees ( ie she's laying over on her side with the deck vertical ) But she wont go bottom-up , ie capsize , because the weight low down in the hull will whip her back upright again .
Sailing yachts , for example , can mostly do this , ie " come back " from a 90degree roll , and our rescue service Lifeboats can self-right , ie you can roll them upside down and they'll come back .
(The opposite case is a ship which is " TENDER " by which is meant a ship with a fairly high centre of gravity .
Imagine one of those modern big square truck ferries overloaded , or a modern "high-rise" cruise liner with a rock concert on deck and all her bottom tanks empty and you get the idea .
That ship will roll reluctantly and slowly and will be sluggish in a moderate or worse sea state . Pushed far over , she will capsize .)
Ship designers try to get between these extremes usually , for the stiff ship is exhausting to her crew , as she throws them
( and anything loose inside ) about , while the tender one is liable to drown everyone in her . You can add various "cheats" as well , like anti-rolling tanks , bilge keels , stabiliser systems and so on , to quiet down a lively ship .
As you know , surface warships need to be as stable as possible but at the same time be extremely seaworthy , so this is where the naval Architect earns their money !
So your short answer is , you could balance a 3 ton truck on top of that tower and she'd just rock a bit from side to side .
The sea-worthiness bit is simply that the sub , divided into numerous watertight compartments and actually DESIGNED to be sunk deep under water , can go through anything Nature can throw at her on the oceans , even silly things like those waves in the films - "Perfect Storm" , "Posiedon Adventure" , "Day after Tomorrow" . You just get inside and close the hatches . If you were on the surface you'd get thrown about but you would plunge straight through .
You are actually better off than you would be in a tanker , the next hardest thing to sink through weather .
Im going to have a "Google earth" around the Baltic/France and see if we cant pin this down - by the sun shadows its either calm still morning , in which case we are looking North ( ish ), or its calm still pm/evening and we are looking South ( ish )
Those moles were generally made of best Granite , so It'll still be there .
I'll have a look for old captured coastal subs candidates as well , and see if there are some possibles .
" Relax ! No-one else is going to be fool enough to be sailing about in this fog ."