To give some examples of todays submarine capabilities check out the following data;

World War II German U-boats had estimated collapse depths of 200 to 280 metres or 660 to 920 feet.

Collapse Depth of a Type XXIII U-Boat is 180 meters or 591 feet with a max speed of 9.7 knots surfaced and 12.5 knots submerged.

Submarines of the 60s - 70s

America - Test Depth of a Permit class submarine is 400 meters or 1300 feet with a max speed of 15 knots surfaced and 28 knots submerged.

Modern Submarines

Modern nuclear attack submarines are estimated to have a test depth of 490 meters or 1600 feet, which would imply a collapse depth of 730 meters or 2400 feet.

Britain - Test Depth of an Astute class submarine is 300+ meters or 984+ feet with a max speed of 18 knots surfaced and 29+ knots submerged.

Britain - Maximum Operating Depth of a Trafalgar class submarine is 600 meters or 1968 feet with a max speed of 20 knots surfaced and 32 knots submerged.

SSBNs

Britain - Maximum Operating Depth of a Vanguard class submarine is X meters or X feet with an estimated max speed of 20 knots surfaced and 25 knots submerged.

Russia - Test Depth of a Typhoon class submarine is 400 meters or 1300 feet with a max speed of 22.22 knots surfaced and 27 knots submerged.

Russia - Test Depth of a Borei class submarine is 450 meters or 1476 feet with a max speed of 15 knots surfaced and 29 knots submerged.

France - Test Depth of a Triomphant class submarine is 400 meters or 1300 feet with a max speed of 25+ knots.

America - Test Depth of a Ohio class submarine is 240+ meters or 800+ feet with a max speed of 12 knots surfaced and 20-25 knots submerged.

http://www.armedforces.co.uk/navy/listings/l0011.html

http://www.royalnavy.mod.uk/The-Flee...Vanguard-Class

http://webarchive.nationalarchives.g...arines-(ssbn)/

http://www.ssp.navy.mil/about/history_facts_5.shtml

http://www.militaryfactory.com/ships...S-Vanguard-S28

http://www.submarineheritage.com/van...ery_pftxt.html

http://www.world-nuclear.org/info/No.../#.Ud8kqkpwbDc

http://www.fas.org/man/dod-101/sys/ship/deep.htm

http://en.wikipedia.org/wiki/Typhoon-class_submarine

http://en.wikipedia.org/wiki/Borei_class_submarine

http://en.wikipedia.org/wiki/Le_Trio...lass_submarine

http://en.wikipedia.org/wiki/Ohio-class_submarine

http://en.wikipedia.org/wiki/Astute-class_submarine

http://en.wikipedia.org/wiki/Permit-class_submarine

http://www.naval-technology.com/projects/astute/

http://www.militaryfactory.com/ships...MS-Astute-S119

http://www.military-today.com/navy/astute_class.htm

http://www.uboatarchive.net/U-570DesignBook.htm

http://www.uboataces.com/uboat-type-xxiii.shtml