Historical crash dive time for fleet boats?

[Ducimus]

Enquiring minds want to know. How long did it take a Tambor, Gato, or similar sub take to get under on a crash dive? Ive looked everywhere, i can't find this info. Making this post is my last resort :88)

[akdavis]

I believe a minute was the "standard" time, but several memoirs (Gato-class subs) note crews training hard to reach 30-35 second dives.

[Ducimus]

So i guess that 1 min and 10 second crash dive in stock is a bit much eh? I toned it down to 58 seconds or so, but was contemplating the feasiblity of shortning it even more. Sort of doing my homework on it as it were.

[OS3 Slickvic]

Well I can understand your frustration. I had gotten so used to ~35 second crash dives in SH3. I do realize that the American boats were not as fast to carry out a crash dive, but Damn......What are you guys doing down there when I issue a crash dive, throwing a keg party or what? :dead: :hmm:

I swear to god you guys are half asleep when you throw the levers to flood the tanks!!
I better start seeing some urgency around here soon or some of you guys are swimming back to Pearl! :nope:

[NEON DEON]

So i guess that 1 min and 10 second crash dive in stock is a bit much eh? I toned it down to 58 seconds or so, but was contemplating the feasiblity of shortning it even more. Sort of doing my homework on it as it were.

It is hard to put an exact figure on a crash dive. Fluckey used to flood negative while surfaced if he was expectiing trouble.

The Narwhal (much bigger than a fleet boat) spotted a japanese aircraft comming straight on them from 7000 yards and crashed dived. She past 50 feet when the bomb hit the water.

The Pampanito web site claims 30 second crash dives for a Balao class.

I have read accounts of boats going to 165 feet and level in 70 seconds.

I have read stories of green crews fresh out of dive school diving in 60 seconds.

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 dont know how much of a factor crew has in effecting dive speed in SH IV. If it plays a part that is effected by crew exp., then I would set it at 60 seconds worst and 30 seconds best with 45 being the average. It really should be crew dependent.

Anyways. That's my story and I am sticking to it.

[AVGWarhawk]

I just read that 50-60 seconds was the average time. This is from the XO of Trigger in his book "Submarine!".

[Bilge_Rat]

From what I read, 60 seconds was the average, fleet boats took longer to dive than U-Boats. Personally, I would not set it at less than that.

[Loaf]

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

[Sailor Steve]

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



*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.

[AVGWarhawk]

http://www.pashnit.com/roads/cal/USSPampanito.htm


Here it shows with practice the sub could submerge in 30 seconds. It might be related to the type of sub as well. Anyway, nice article. Note the picture of the sub going off the dry dock. Looks like the same pic in the game.

[Onkel Neal]

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 :(

[AVGWarhawk]

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 :(

Yahoo! The new CEO of the "2nd Patrol Your Dead Club":up:

[Bilge_Rat]

nice photos. I read an excerpt of a book once, a war memoir of a U.S. submariner who in intensive training with his new crew had gotten the dive time down to, I believe 50-60 seconds, although I don't remember where now, (ed Beach maybe). 30 seconds seems a tad fast.

[Captain_Jack]

My crews are able to crash dive in under 60 Seconds..

The Historical accounts I have read say the same.

[simsurfer]

The USS Nerka dove and sank a Akikaze DD in 32 seconds. :arrgh!:

[Floyd]

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

Put the crew to battle station and the boat should dive way faster. Time might be affected
by fatigue status of crew, but i have no real numbers. I forgot my crew on battle station
once and all were approx. 90-99 fatigue. Had the impression that every command
too very long to be followed. Oh, and the engines stopped.

[NEON DEON]

An excerpt from the USS Pampanito web site.

"A World War II submarine spent most of its time on the surface where it could travel quickly and more easily find its targets. She dove to make stealthy attacks or escapes from the enemy. To make it possible for the crew to walk outside the boat while on the surface, and to protect equipment that is not in the pressure hull, the main deck is built up over the pressure hull. The space between the pressure hull and the deck is the free-flooding superstructure. The many holes that are visible allow air to escape and water to flood this space. Any trapped air would slow down the dive. Pampanito can go from the surface to 60 foot depth in under 30 seconds."

http://www.maritime.org/tour/tadeck.htm

Anyways that's my story and I am sticking to it.

[Sgian Dubh]

I don't have much to add in terms of factual data, but I can tell you that if you travel with 'desk awash' in SH4, the dive time is greatly reduced, mainly because the dive-planes are already run out and (I guess) the boat is already cloaser to neutral boyancy.

I only travel this way on the surface during the day. Even with the short range of the "Plane!" calls, I am under long before the plane can get to me.

[AVGWarhawk]

I don't have much to add in terms of factual data, but I can tell you that if you travel with 'desk awash' in SH4, the dive time is greatly reduced, mainly because the dive-planes are already run out and (I guess) the boat is already cloaser to neutral boyancy.

I only travel this way on the surface during the day. Even with the short range of the "Plane!" calls, I am under long before the plane can get to me.

Nice to know but I love shooting the twin .50's at the planes:yep:

[Sgian Dubh]

you can run 'desk awash' and shoot the gun yourself.

The watch crew is still on the bridge as well.

[AVGWarhawk]

you can run 'desk awash' and shoot the gun yourself.

The watch crew is still on the bridge as well.

Yes, I know but I like staying surfaced and shooting away:yep:

[sgt.weasle]

you can run 'desk awash' and shoot the gun yourself.

The watch crew is still on the bridge as well.

when i run 'desk awash' my computer crashes every time..:D :lol:

(lol jk)

[Bilge_Rat]

just to add more fuel to the fire, I was skimming through the online version of "The Fleet Type Submarine" http://www.maritime.org/fleetsub/index.htm

In chapter 18A dealing with diving, it states:


18A2. Types of dives

Three types of dives are possible: 1) the quick dive, 2) the running dive, and 3) the stationary dive, the choice being dictated by existing conditions. In all dives the ship is placed in the condition of neutral or negative buoyancy; the use of negative buoyancy shortens the diving time. A quick dive is made when the ship is underway on one or more main engines. The bow planers are placed on FULL DIVE and the forward speed results in a maximum downward thrust on the bow planes. As the submarine submerges, the upper surfaces of the hull and superstructure act as planing surfaces and increase the downward thrust. The quick dive is the fastest of the three types and is used in acceptance trials of new submarines, when it must be executed within 60 seconds from standard diving trim.

This seems to imply that the US Navy standard was for the dive to be completed in 60 seconds. Certainly, a crew testing to achieve the quickest time could possibly dive in 30 seconds, but if a boat is surprised and does an emergency dive, 30 seconds from the dive order to periscope depth seems a little tight.

[NEON DEON]

just to add more fuel to the fire, I was skimming through the online version of "The Fleet Type Submarine" http://www.maritime.org/fleetsub/index.htm

In chapter 18A dealing with diving, it states:


18A2. Types of dives

Three types of dives are possible: 1) the quick dive, 2) the running dive, and 3) the stationary dive, the choice being dictated by existing conditions. In all dives the ship is placed in the condition of neutral or negative buoyancy; the use of negative buoyancy shortens the diving time. A quick dive is made when the ship is underway on one or more main engines. The bow planers are placed on FULL DIVE and the forward speed results in a maximum downward thrust on the bow planes. As the submarine submerges, the upper surfaces of the hull and superstructure act as planing surfaces and increase the downward thrust. The quick dive is the fastest of the three types and is used in acceptance trials of new submarines, when it must be executed within 60 seconds from standard diving trim.

This seems to imply that the US Navy standard was for the dive to be completed in 60 seconds. Certainly, a crew testing to achieve the quickest time could possibly dive in 30 seconds, but if a boat is surprised and does an emergency dive, 30 seconds from the dive order to periscope depth seems a little tight.

The boat is moving they flood negative and set the planes. Is that an acceptance trial for the boat done by a civilian crew? Sounds like it is a trial for the boat itself.

[Ducimus]

So far im guessing that from crusiing on the surface at 8 kts, and hitting crash dive, the boat should be completely covered with water with only the little pole on the stern protruding on the surface - in about 45 seconds?

[NEON DEON]

Maybe a test should be run to see how much crew training is factored in.

Hack it a bit with the most elite crew you can come up with and time it till the point that the boat is no longer visible.

Then run the same test with a bunch of Newbies.

Just to see what the extremes are so you have a gauge you can use to adjust it.

[Sailor Steve]

The USS Nerka dove and sank a Akikaze DD in 32 seconds. :arrgh!:
:rotfl:

That's great!

It's true! I saw it too!

[Ducimus]

Maybe a test should be run to see how much crew training is factored in.

Yeah im wondering about that.

[jerryt]

Has anyone done a crash dive in really rough seas? It took forever to get below the surface! :o I didn't time it, but it was way over the usual time.

I'm thinking maybe the dive planes couldn't get a good bite because of the wave action? They were in and out of the water. Anybody know if this would be a realistic behavior?

On another note. Surfacing in really rough weather seems to take a long time to get well above the surface. I notice even in calm seas, it takes a while for the boat to get completely to zero depth, but when its rough I sure can't send my lookouts above deck for a few minutes. I have to use the periscope for safety. :p

[NoLine]

Anybody notice the s-boat crash diving in 15 seconds, which seems a bit short

NoLine

[Prof]

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:

[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



*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.

[DeePsix501]

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.

[Ducimus]

Thanks for the test Prof. :up:

[-Pv-]

"... 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-

[Captain_Jack]

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.


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.

[Ducimus]

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.

[NEON DEON]

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.

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.

[Bilge_Rat]

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;

[Front Runner]

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;

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....

[Faamecanic]

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.

[Bilge_Rat]

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.

[Faamecanic]

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.

[NEON DEON]

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.

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.

[MadMike]

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

[jmjohnson36]

I asked my grand-dad on dive times ( he was a subbie in WW2) he thought it was 90 seconds from bell to 45ft. Hes 89 so....