SUBSIM Radio Room Forums - Historical crash dive time for fleet boats?

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OK, I just did a test in career mode with a Balao class in 1945.

Dive 1: Best crew I could get in port (particularly 'engines' and 'command'). Went to flank on surface (19 kt) and sent crew to battle stations. Crash dived and started stopwatch.
The shears went underwater after 48 seconds and the boat was pretty much level after 1:50.

Dive 2: Emptied the submarine of all except one recruit in each watch in each section. I filled the watch crew with recruits so that there would be the same number of crew having to 'get down the hatch'. Sent sub to flank (18-19 kt) and crash dived.
The shears went under at 46 seconds.
After that I got the FPS-killing bug so I don't know how long it took to get down deep.

Anyway, it would seem that the crew efficiency makes no difference :down:

Quote:

Originally Posted by Sailor Steve

Quote:

Originally Posted by NEON DEON

Since fleet boats are true diesel electric boats they dont lose all power to the screws like a direct drive U boat or S class. So once the planes are down and they have neutral bouancy or less they now are flying in the water and speed takes over.

I went to the Fleet-Type Submarine Manual looking for a hint about dive times; didn't find any, but this section indicates that they did lose power to the screws momentarily:
http://www.maritime.org/fleetsub/chap18.htm#18A

Quote:

*a. Stop all engines, shift to battery, set annunciators on "All ahead standard," open engine room doors and air locks.

*b. Close outboard and inboard engine exhaust valves, close hull ventilation supply and exhaust valves, close inboard engine air induction flappers, and close conning tower hatch.

*c. Open bow buoyancy vents and all main ballast tank vents, except the group or tank designated to be kept closed until pressure in the ship indicates that all hull openings have been closed.

*d. Rig out bow planes and place on FULL DIVE. Use stern planes to control the angle on the ship.

*e. Diving officer checks hull opening indicator light panel for condition of hull openings. Air is bled into the ship when green lights show all hull openings closed. Watertight integrity is assured when the internal air pressure remains constant.

f. The following operations are performed by direction of the diving officer, who is guided by the existing conditions:

1. At 45 feet, shut the vents and slow to 2/3 speed.

2. At 15 feet short of desired depth, blow negative tank, shut its flood valve, and vent the tank.

3. Level off at specified depth, slow to 1/3 speed, cycle the vents, and adjust fore-and-aft trim and over-all weight.
4. Diving officer reports to conning officer when trim is satisfactory.

Of course that might explain why it took so long to dive.

Steve, the stop all engines they refer to are diesels that are shut off. The props are not run by engines but by motors. Electric motors not engines. The diesels are not connected to the prop shafts. The power source is transferred at the switchboard by means of a lever. The switchboard itself regulates the transfer while the motors are still running. You will get a drop in rpm when on battery but the props don’t stop.

I've run practice drills on my sub and I can get her under in about 30-32 secods. I'm pretty sure that is accurate timing, as i'm reading Take Her Deep by I.J. Galantin and I think he says that he got his ship under in thirty seconds or so. If I find a direct quote, i'll post it.

Thanks for the test Prof. :up:

"... On another note. Surfacing in really rough weather seems to take a long time to get well above the surface..."

It takes less time to flood the main ballast then to pump out the remaining water again on the surface. The sub stays water loged for a little while.
-Pv-

Quote:

Originally Posted by DeePsix501

Same findings here. And down to periscope depth within 60 Seconds...From what I have read and from what is discussed by Veterans in the Silent Service series that is accurate.

After you dive, and resurface the game models water being in the ballast tanks. During this time you can make some fast dives. However after about an hour or two game time, your ballasts are bone dry again. So unless you plan on doing trim dives every couple hours, i woudlnt bet my boats survival on that effect. Its only handy if your surpised while surfacing.

Quote:

Originally Posted by Ducimus

Maybe thats why Fluckey flooded the negative tank in enemy territory.

I did some dives today in a Balao and the first dive took about 45. The second one was 30. I even got one dive where the shears dissappeared in 25 seconds.

flipping through Silent Victory, I found some more info:

- the P-class and Salmon class could dive "within 60 seconds";

-the Tambor class could dive to periscope depth (60 feet) in 35 seconds;

-no info on Gato or Balao class;

Quote:

Originally Posted by Bilge_Rat

It would be nice to be able to "drill" the crew to improve
1. Dive times. (with green crews slower than vets, but able to improve before arriving on station.)
2. Battle Stations Surface and Submerged
3. Deck Gun Accuracy
4. AA Gun Accuracy
5....

Quote:

Originally Posted by Neal Stevens

Quote:

Originally Posted by Loaf

Does anybody know if crew experience affects dive times in SHIV?

That's what I was wondering... anyone timed crash dives with a green crew and with a vet crew?

I keep starting new careers so I have yet to get more than 2 patrols with one crew :(

Green crew on a GATO type sub (Patrol 2) and was 75 seconds from Crash dive order to the whole sub being submerged at 40 feet (antenna just under the water) on a clear day.

one more thought:

- I presume the best times of 30-35 seconds were achieved under ideal conditions, namely sub at best speed, best sea conditions, fresh crew specificallly training for quick time.

-but in a more typical battle scenario, for example a lookout spots an airplane/ship and the OOD orders a dive, the sub is moving at cruising speed, the sea conditions are probably less than ideal, the crew is not at battle stations and is probably a bit tired from a few weeks/months at sea, 45-60 seconds is probably more typical.

I can buy 45-60 seconds....but 75 seconds!!! And those Dead Eye Dick Jap bombers almost NEVER miss. Needless to say the only way to avoid the aircover is to stay submerged during the day and only run on the surface at night.

Quote:

Originally Posted by Faamecanic

It is the first dive that will get you killed. The second dive should get you under in about 30 to 40 seconds. Of course, you have to dive every two hours to get the benefit. No proplem if you are in japanese home waters. The air cover should force you down a lot.

George O. Jones writes in his online memoirs as an S-boat crew member that riding the vents they could dive in 30 seconds (!).

http://www.geocities.com/goliverjones/home.htm

Yours, Mike