underwater mines approaching scapa

[Bent Periscope]

Paul,
Your answers sound very reasonable, I'll try them if I get lost or have to cross a mine field.
Now, how do you recommend I attack a convoy with 8 destroyer escorts while not being detected?
Thanks,
BP

[Paul Riley]

Personally? I would probably not attack it,that is a very well defended convoy,perfectly capable of annihilating a UBoat in a millisecond.However...and I stress however,it all depends on the player's skill and level of courage.I am a more cautious player that likes to work out carefully my chances.
Don't forget,some of the greatest generals knew when to retreat.
Just a thought,if you are adamant to engage this convoy,how about setting off Bold decoys away from your position,in order to try and pull away some of that muscle from the convoy?
Really though,i'd leave it,extremely hazardous to pull off

[karamazovnew]

On the east coast of Britain I run into lots of minefields. They're usually in water deeper than 50m. I've seen most at 20m deep but also some as deep as 50-60 m. They made me change my tactic when dealing with convoys. I run as little as I can underwater and dive only when I must. However this raised a morality issue. Did the real skippers look through the periscope underwater to dodge mines and sub nets, or to see how far they are from the sea floor? Or even to dodge that pesky DD? Sure, at night that's impossible to do but during daylight, the water seems to be too clear. Didn't they have a maximum depth at which they could raise the perisope without the lens cracking from the pressure?

[Leandros]

Originally Posted by karamazovnew

Sure, at night that's impossible to do but during daylight, the water seems to be too clear. Didn't they have a maximum depth at which they could raise the perisope without the lens cracking from the pressure?

This is of interest to know. Does anybody know...? I have run into mines on the East coast in the early war. They are obviously contact mines - not magnetic since they are not going off when passing them. They are also positioned such that when on PD you shall just pass over them.

On several occasions when leaving Bergen in the late war I have been mined. These were obviously magnetic. When following in the track of the VP-boat out the fjord I was never mined.

[Jimbuna]

The British did lay a large minefield (as well as among other areas) almost the entire length of the east coast.

The North Sea has very dark water, therefore in RL raising the periscope whilst submerged would allow you to see perhaps a few feet beyond the bow of your sub.

Anything else IMO is simply unrealistic.

[_Seth_]

Originally Posted by jimbuna

The British did lay a large minefield (as well as among other areas) almost the entire length of the east coast.

The North Sea has very dark water, therefore in RL raising the periscope whilst submerged would allow you to see perhaps a few feet beyond the bow of your sub.

Anything else IMO is simply unrealistic.

Jim, do you know if it's possible to get a map over the allied minefields of WWII around the islands (GB, Ireland, Orkney & Shetlands) ?
I suppose that the Germans in addition dropped mines from aircrafts around the allied harbours, to destroy allied shipping. But these mines could do damage to a german sub aswell, could'nt it?

[Jimbuna]

Originally Posted by _Seth_

Jim, do you know if it's possible to get a map over the allied minefields of WWII around the islands (GB, Ireland, Orkney & Shetlands) ?
I suppose that the Germans in addition dropped mines from aircrafts around the allied harbours, to destroy allied shipping. But these mines could do damage to a german sub aswell, could'nt it?

I've a few sets of Admiralty Mine Charts but they are of the south, south east and east coasts.

They may also be copyrighted ....I'm not entirely sure

The Germand did indeed drop mines from aircraft, but mainly from subs and Schnellbootes and U-boats, but nothing like in the numbers the Allies did.

[Platapus]

Originally Posted by karamazovnew

O Didn't they have a maximum depth at which they could raise the perisope without the lens cracking from the pressure?

To prevent lens cracking, I don't think so. In looking at the schematics of the Type VII, the objective lens (end that sticks out of the water) is always exposed to the pressure that is exerted by the depth of the submarine.

Even when it is fully retracted, the objective end is in a protective sheath but still exposed to the water and its pressure. This means that the periscope lens was designed to withstand the pressures that the submarine was designed to withstand.

However, that does not mean that the periscope could be extended at any depth. It is not the lens cracking that would be worrisome but the seals leaking. When the periscope is fully retracted, a special heavy-duty seal is engaged to help protect the smaller seals. When extending the periscope at depth, the many small seals may be subject to a pressure they were not designed for.

So from a seal integrity standpoint, I am sure there was a maximum depth in which the periscope could be safely extended. But not one for the lens cracking.

In looking at the design of the periscopes, I would imagine the submarine would crack before the lens would crack.

As for being able to see underwater through the periscope, that would be dependent on the light available. One could see much better looking up through the water against the light background of the sky (during day of course) than one could see looking in front where the background is banal.

At depths of about 30 meters, it gets pretty dark/murky at times. I seriously doubt you could see a tethered mine far enough to be able to take evasive action.

Now if you were on the side of the good guys (Americans) you might have had access to the OL and OLA special purpose sonars which were designed to find underwater objects such as mines.

[Leandros]

Originally Posted by Platapus

To prevent lens cracking, I don't think so. In looking at the schematics of the Type VII, the objective lens (end that sticks out of the water) is always exposed to the pressure that is exerted by the depth of the submarine.

Even when it is fully retracted, the objective end is in a protective sheath but still exposed to the water and its pressure. This means that the periscope lens was designed to withstand the pressures that the submarine was designed to withstand.

However, that does not mean that the periscope could be extended at any depth. It is not the lens cracking that would be worrisome but the seals leaking. When the periscope is fully retracted, a special heavy-duty seal is engaged to help protect the smaller seals. When extending the periscope at depth, the many small seals may be subject to a pressure they were not designed for.

So from a seal integrity standpoint, I am sure there was a maximum depth in which the periscope could be safely extended. But not one for the lens cracking.

In looking at the design of the periscopes, I would imagine the submarine would crack before the lens would crack.

As for being able to see underwater through the periscope, that would be dependent on the light available. One could see much better looking up through the water against the light background of the sky (during day of course) than one could see looking in front where the background is banal.

At depths of about 30 meters, it gets pretty dark/murky at times. I seriously doubt you could see a tethered mine far enough to be able to take evasive action.

Now if you were on the side of the good guys (Americans) you might have had access to the OL and OLA special purpose sonars which were designed to find underwater objects such as mines.

Good info!