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View Full Version : Battery endurance with subs ALL WRONG, maybe.


Jib01
02-24-08, 06:05 PM
I'll relook at this but it sound interesting....

World War II vintage submarines, while diesel driven when on the surface were battery powered once submerged. The ASW units that were able to remain on a contact and keep it under for extended periods could eventually force the sub to expend its valuable battery resources. Prior to Germany's use of the schnorkle (which allowed a U-Boat to remain at periscope depth and use their diesel engines for propulsion) the maximum submerged endurance of a sub was approximately 50 hours. The purpose of the hold-down was to keep the submarine submerged to a point of suffocation, desperation or exhaustion. Once available oxygen and power was down to a critical level, the submarine would have no choice but to surface and duke it out with the destroyers waiting above. Extended depth charging would also have a very powerful effect on the nerves of the submarine crew. In a surface battle, the favor would rest with the destroyers, although many a wily U-Boat commander has escaped after many hours of deep submergence and depth charging under the cover of darkness. That is to say that the destroyermen had to be particularly vigilant at nightfall. A submarine that could surface undetected could engage its diesel engines and quite possibly escape.

Found another one which is better....

BALAO CLASS SPECIFICATIONS

Overall Length x Maximum Breadth: 311 ft. 9 in. x 27 ft. 3 in.
Displacement: 2,010-2,075 tons Surfaced; 2,415 tons Submerged.
Operating Depth: 400 feet.
Watertight Compartments: 8 plus conning tower.
Pressure Hull Plating: approx. 7/8 in. high tensile steel.
Torpedo Tubes: 6 bow; 4 stern; max load = 24
Deck Guns: 1 4-in./50-cal. or 1 5-in./25-cal.
Maximum Speed: 20.25 knots surfaced; 8.75 knots submerged.
Cruising Range: 11,000 miles surfaced at 10 knots.
Submerged Endurance: 48 hours at 2 knots with lowest at 36hrs for S boats.
Fuel Capacity: 116,000 gallons.
Patrol Endurance: 75 days.
Propulsion: Diesel-electric reduction gear with 4 main generator engines,
1 aux. generator.
4 main motors with 2,740 shaft horse power.
2 126-cell main storage batteries.


I have been suspicious of the underwater endurance for awhile and this kinda points this out. And it says batteries endurance of 50 hours. And it could mean combined battery and oxygen endurance but it does not say that but I think that is what it means.

Our subs have an endurance of 9-10hrs at Standard with about 10% left. If someone can point me to a better reference please do so otherwise where do we make the change for longer battery life in the game ??

Regards
jib01
:hmm: :hmm: :hmm: :roll: :roll: :roll:

swdw
02-24-08, 07:46 PM
When reading reference info you need to be careful you don't just jump at every "boo".

These numbers assume normal underwater opearting equipment and do not take into account the extended life you could get by securing as much equipment as possible. For example, running silent where all non-essential electrical equipment is secured, etc

You should look at the sub's sim files. They are in miles per knots. For example, one boat is 84 miles at 4 knots- you do the math.

In addition, this does not include things like coasting in between engine runs to extend battery life. If an electrical motor isn't turning it draws little current.

Sailor Steve
02-24-08, 10:07 PM
Our subs have an endurance of 9-10hrs at Standard with about 10% left. If someone can point me to a better reference please do so otherwise where do we make the change for longer battery life in the game ??
"Standard" is not 2 knots. How long can you go at two knots?

LukeFF
02-25-08, 02:23 AM
Nonetheless, there does seem to be issues with underwater endurance times. Running at flank speed, for instance, in a fleet boat should drain the batteries in 30 minutes (it was known as the "30-minute rule." In SH4 I can run at flank speed submerged for triple that amount of time.

Will be interesting to see if anything has changed with the add-on.

M. Sarsfield
02-25-08, 07:17 AM
Have any of you installed the "surface draft and dive time mod"? They modified the endurance values for surface and underwater operation. I'm pretty happy with the performance that I'm getting from this new mod.

Jib01
02-25-08, 10:07 PM
Have any of you installed the "surface draft and dive time mod"? They modified the endurance values for surface and underwater operation. I'm pretty happy with the performance that I'm getting from this new mod.

I installed it but it was missing mods for the Narwhal boat. Anyway after the install I did some testing and got this for the Narwhal boat.

Crusing under water endurance....

2 Knots = 39hrs
4 knots = 14hrs
6 knots = 8hrs
8 knots = 6.5 hrs

As long as I know I can get this endurance from 2 knots that will be fine. Usually I would be crusing under water at Standard which is 6 knots.

Thanks
Jib01
:up: :up: :up: