1 meter per 20 seconds!?

[applesthecat]

What is a normal descent/ascent rate for a type vii sub? I find that my sub goes up or down by about 1 meter every 20 seconds and perhaps only a little faster with blow tanks or crash dive.

Is this normal? The sub had a nose down attitude of only about 5 degree when descending. Also, is there a way to manually manipulate the dive planes, like on silent hunter I to dive faster?

I also found I could not rise with my engines off. Shouldn't blowing ballast rise the sub regardless of forward speed? Don't subs rise by positive buoyancy?

I had no damage to my dive planes.

Thanks

[Firebird]

I can only say that it's way too slow . When crashdiving it should probably be more like 1m/1s.

It's not possible to manually manipulate the dive planes.

Yes, you should be able to rise without engines... and blowing ballast should get you to the surface fast.

[Paul Riley]

I find blowing just half the tanks in an emergency surface is that fast,the sudden blast of oxygen at the surface into the boat almost knocks the men out

[Schroeder]

You have to use some speed to make your sub respond to dive-plane inputs. No speed = no pressure on the planes = no changes in depth.

[Jimbuna]

The way the game is coded means speed is the key I'm afraid....the faster the speed, the faster the descent.

[PappyCain]

I find blowing just half the tanks in an emergency surface is that fast,the sudden blast of oxygen at the surface into the boat almost knocks the men out


Hypoxia is a pathological condition in which the body as a whole (generalized hypoxia) or a region of the body (tissue hypoxia) is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise. A mismatch between oxygen supply and its demand at the cellular level may result in a hypoxic condition. Hypoxia in which there is complete deprivation of oxygen supply is referred to as anoxia. When there is flatulence in a sub when under pressure, the men will experience euphoria a condition that is overcome by flatulence with particulate which is to be avoided. A rush of salty clean AIR (not oxygen)will cause the inner ear to pop causing a distress on the knee joints and a relaxed bowel movement on those seated. This was a known issue and was never treated in the training manuals. Notice all the men stand up when opening the hatch (in all movies).

[Paul Riley]

Interesting pappycain
Farting causes euphoria eh,not after a hard night at the pub it doesnt :rotfl:

[PappyCain]

Yes. and remember sauerkraut gas with particulate can cause stitching in pants to dissolve. That is why monofilament was created. Most people think it was the sport fishing industry. Nope. Another technology transfer from WW2. I myself developed offgassing expertise in hyperbaric chambers. One can appreciate a euphoria when one's intended target cannot escape.

[Bent Periscope]

Has anyone tested speed of dive versus speed of descent?

I'm wondering how fast you'd get to 70 meters a crash dive as opposed to a 2 knot silent descent.

Also, how much slower would you descend if you are also turning to present a smaller target or trying to throw off a DD?

BP

[Jimbuna]

The difference would be considerable....the faster the speed, the faster the descent rate.

[PappyCain]

Imagine yourself in a pool. You want to pick up a quarter on the bottom. Will you get there faster if you kick your way to the bottom? or if you just exhale and sink? Jimbuna (who has many quarters) is on the mark. Test it out in the sim. Time it and give us a report!



I usually run a crash dive test with every boat and crew to see what it can do under best circumstances. My memory on my IXB at 17 knots, calm sea conditions, both screws turning, I can get to 50m in about 60 seconds (and 70m fully trimmed in about 120 seconds). I am always running at max speed when on the surface at this date in the war (1944 Fall) so I can dig down fast as possible.

[Sailor Steve]

Wait wait wait hold on just a second!!!

1 meter every 20 seconds is too slow? When crash diving 1 meter per second should be right?

17 knots = 31,852 meters per hour. That's 524.7 meters per minute. That's 8.7455 meters per second. That's the sub's forward motion. That would be it's dive speed if it was going straight down at flank speed. I'm not real good with math, but it looks to me like 15-degrees on the planes would give you 17% of that, which is about 1.46 meters per second.

What's the maximum angle available on the planes? If it's 30 you're only going to get about 3 m/s. And that's at 17 knots!

These aren't airplanes, they're 800-ton ships.

Also, as to the running complaint about not being able to man the dive planes yourself, it wasn't like a modern sub where one guy has an aircraft-style yoke and can both steer and control dive angles. Two guys manned the fore and aft planes, and they could only move them as much as they were told to, and that wasn't much. Eight hundred tons carries a lot of momentum. The game crash dives you to 70 meters because once they started down in an emergency it took them that long just to pull out again. You want to go down faster? Not me, thanks.

[applesthecat]

Steve, are you saying that 1 meter in 20 seconds is correct? If you blow your ballast tanks in any sub, you rocket to the surface. Even diving at standard speed should get you to 100 meters in a few minutes. It's not just your forward speed in the equation - there is gravity - you are flooding and sinking. Nonetheless, it takes me over half an hour to get to 100 meters! Something is not right.

[Jimbuna]

Originally Posted by Sailor Steve

You want to go down faster? Not me, thanks.

Me neither...thanks

[PappyCain]

Boot ist nicht zu halten!

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