SUBSIM Radio Room Forums - View Single Post - Diving Depth- how common do modern subs go really deep- and how useful is it?

ACR · 08-28-13, 05:20 PM

the actual depth ratings for current nuclear subs are classified so we can only use general information .

and we have to clarify what exactly depth rating we are talking , maybe also available data mixes the different depth ratings .

basicly we have :

test depth which has a big margin to the actual crush depth, the margin depends on the different navies . afaik thats the maximum depth which is approved for normal peacetime operations .

maximum operating depth : the maximum depth a sub can operate in extreme combat conditions. afaik this depth results in a high stress and wear on the hull and systems and is so only approved on wartime scenarios otherwise the life expectancy of the hull would be very low.

design depth : the calculated maximum pressure the hull will cope with , but without quarantee the systems on the boat will work and pipelines/ fittings etc will make it . there is also a small margin to the crush depth to cope with hull wear when the boat gets older.
this depth is not approved for any situation

crush depth : well, the depth the hull will be crushed when stressed beyond any limits , also calculated and never ( intentionally ) tested.

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

further i think we talk wrong numbers and the actual depths current subs go are way less.

we can learn from tresher accident. the hull was build from HY-80, so the same like the 688I . and the hull crushed finally at 1300-2000 feet .

http://en.wikipedia.org/wiki/USS_Thresher_%28SSN-593%29

assuming the 1.5 safety factor of the US navy it would push tresher to roughly 800 feet test depth and maybe 1000-1200 feet maximum operating .

with the construction of the los angeles class rickover wanted speed at any cost and finally due to the weight of the massive powerplant he had to reduce hull thickness for saving boat mass to keep the boat floatable at all. he accepted it to keep speed because depth was not that important in his eyes.

build from the same material like the tresher i do not see any chance the 688 can dive deeper and with the hull thickness reduction there are good chances the dive depth of the 688 is lower .

how deep ? its classified , but you see on the internet depth ratings like here :

The U.S. Navy gives the maximum operating depth of the Los Angeles class as 650 feet (200 m),[9] while Patrick Tyler, in his book Running Critical, suggests a maximum operating depth of 950 feet (290 m).[

you also see in some sources a statement "max depth 800 feet"

so what ? what if all these depth numbers have some value but were mixed to different ratings ?

my best guess for the los angeles class is the following :

650 feet test depth ( this implies with the 1.5 us navy factor a design depth of 975 feet and crush of 1000-1200 )

800 feet maximum operating

950-975 feet design depth and maybe 1000-1200 feet crush depth .

when we see the HY-80 AND thicker hull tresher crushed at about 1300-2000 feet it seems plausible the crush depth of the 688 might be in the area of 1000-1200 as a rough guess.

when i,m roughly correct the 1475 feet max operating in dangerous waters of the 688 is only a myth . lets also rember max operating is still a good margin away from crush .

there were good statements made that deep diving has nearly no use in military sub operations and the silent and fast 688i is even with a low diving depth a powerful submarine .

best regards !

08-28-13, 05:20 PM	#7
ACR Seaman Join Date: Dec 2008 Posts: 42 Downloads: 19 Uploads: 0	the actual depth ratings for current nuclear subs are classified so we can only use general information . and we have to clarify what exactly depth rating we are talking , maybe also available data mixes the different depth ratings . basicly we have : test depth which has a big margin to the actual crush depth, the margin depends on the different navies . afaik thats the maximum depth which is approved for normal peacetime operations . maximum operating depth : the maximum depth a sub can operate in extreme combat conditions. afaik this depth results in a high stress and wear on the hull and systems and is so only approved on wartime scenarios otherwise the life expectancy of the hull would be very low. design depth : the calculated maximum pressure the hull will cope with , but without quarantee the systems on the boat will work and pipelines/ fittings etc will make it . there is also a small margin to the crush depth to cope with hull wear when the boat gets older. this depth is not approved for any situation crush depth : well, the depth the hull will be crushed when stressed beyond any limits , also calculated and never ( intentionally ) tested. http://en.wikipedia.org/wiki/Submarine_depth_ratings further i think we talk wrong numbers and the actual depths current subs go are way less. we can learn from tresher accident. the hull was build from HY-80, so the same like the 688I . and the hull crushed finally at 1300-2000 feet . http://en.wikipedia.org/wiki/USS_Thresher_%28SSN-593%29 assuming the 1.5 safety factor of the US navy it would push tresher to roughly 800 feet test depth and maybe 1000-1200 feet maximum operating . with the construction of the los angeles class rickover wanted speed at any cost and finally due to the weight of the massive powerplant he had to reduce hull thickness for saving boat mass to keep the boat floatable at all. he accepted it to keep speed because depth was not that important in his eyes. build from the same material like the tresher i do not see any chance the 688 can dive deeper and with the hull thickness reduction there are good chances the dive depth of the 688 is lower . how deep ? its classified , but you see on the internet depth ratings like here : The U.S. Navy gives the maximum operating depth of the Los Angeles class as 650 feet (200 m),[9] while Patrick Tyler, in his book Running Critical, suggests a maximum operating depth of 950 feet (290 m).[ you also see in some sources a statement "max depth 800 feet" so what ? what if all these depth numbers have some value but were mixed to different ratings ? my best guess for the los angeles class is the following : 650 feet test depth ( this implies with the 1.5 us navy factor a design depth of 975 feet and crush of 1000-1200 ) 800 feet maximum operating 950-975 feet design depth and maybe 1000-1200 feet crush depth . when we see the HY-80 AND thicker hull tresher crushed at about 1300-2000 feet it seems plausible the crush depth of the 688 might be in the area of 1000-1200 as a rough guess. when i,m roughly correct the 1475 feet max operating in dangerous waters of the 688 is only a myth . lets also rember max operating is still a good margin away from crush . there were good statements made that deep diving has nearly no use in military sub operations and the silent and fast 688i is even with a low diving depth a powerful submarine . best regards !