Depthkeeping during attacks (?)

Luno · 02-29-12, 06:55 PM

Hi Kaleuns,

I've read that it's really difficult for a sub to maintain a precise depth, and this is especially critical at periscope depth and while making attacks.

Apparently, the sub had to be moving at all times in order to have enough water-flow over the dive-planes and rudder to keep the depth and heading constant.

Is this a valid concern, and is there a mod which addresses this? At what speed, historically, did subs move in order to make a submerged attack?

This would certainly add an interesting element to TDC calculations...

PappyCain · 02-29-12, 07:39 PM

A very good question! Yes, to maintain neutral buoyancy and not use the ballast to trim constantly one had to keep the boat moving as you well state. As to speed it was slow to avoid the periscope making a noticable wake and best done with the sun at your back. That made it harder to spot too.

(Side note: when a torpedo is launched, the weight of the boat had to be immediately balanced with ballast, as the launching of a torpedo caused more than a ton of positive buoyancy. If this was not offset by ballast, the boat could pop to the surface, giving away its position. Many U-boats were caught and abruptly attacked due to this simple error.)

Luno · 02-29-12, 08:09 PM

The player doesn't really have control of the ballast...is the game's ballast-man just that good? (Kinda like how the weapons officer makes no mistakes if you enable him in the difficulty)

Considering that the maximum periscope-up speed is about 4-5kts (due to wake and vibrations), I would image that 1-2kts is sufficient to help keep a boat at the right depth...

If this is so, I may end up imposing this restriction on myself as I play

Kapt Z · 02-29-12, 09:33 PM

I try and always stay at 2kts or below when I raise the scope.

Sailor Steve · 02-29-12, 11:17 PM

NYGM has the "anti-hummingbird" mod built in. Two knots or less and you start to slowly sink.

Harald_Lange · 03-01-12, 05:12 AM

I usually find the track of the target , and plot a course to 5-700m off the track at 90 degrees, and sit there, periscope just under the surface, listening on my hydrophone until the angle is right, then peek and fire at the last moment.

After reading this, it seems what I'm doing is wholly unrealistic.

andwii · 03-01-12, 07:27 AM

ya ive noticed on the boats like IIA that depth keeping at periscope depth is a pain if your not going more then 2 knots, which really isnt all that bad of a speed, its not to loud but it sure is loud enough to give you away in 1942-1943 lol.

u crank · 03-01-12, 07:34 AM

I have often wondered about depth keeping also in regards to realism in SH3/GWX. There are some very detailed explanations of this in Edward Young's great book 'One of Our Submarines'.

http://www.amazon.co.uk/One-Submarin.../dp/1844151069

After reading those sections again I realize that this was not the Captains job. He would tell his officer in charge of this task if the sub was not at the proper depth, but he didn't actually do it himself. This is very well simulated in SH3/GWX. Your helmsman is doing his job very well. No need to yell at him.

Good hunting.

andwii · 03-01-12, 07:40 AM

Quote:

Originally Posted by u crank

I have often wondered about depth keeping also in regards to realism in SH3/GWX. There are some very detailed explanations of this in Edward Young's great book 'One of Our Submarines'.

http://www.amazon.co.uk/One-Submarin.../dp/1844151069

After reading those sections again I realize that this was not the Captains job. He would tell his officer in charge of this task if the sub was not at the proper depth, but he didn't actually do it himself. This is very well simulated in SH3/GWX. Your helmsman is doing his job very well. No need to yell at him.

Good hunting.

wish we could do this more things in SH3, like not having to do the TDC your self, just ordering off the AOB, distance, speed, bearing excreta.

Luno · 03-05-12, 02:30 AM

Quote:

Originally Posted by u crank

I have often wondered about depth keeping also in regards to realism in SH3/GWX. There are some very detailed explanations of this in Edward Young's great book 'One of Our Submarines'.

http://www.amazon.co.uk/One-Submarin.../dp/1844151069

After reading those sections again I realize that this was not the Captains job. He would tell his officer in charge of this task if the sub was not at the proper depth, but he didn't actually do it himself. This is very well simulated in SH3/GWX. Your helmsman is doing his job very well. No need to yell at him.

I totally agree, but I'm just wondering if the helmsman could actually keep the sub at a specific depth if the sub wasn't moving. I don't necessarily want to do his job, I just want to know if it was necessary to keep moving to help maintain depth.

Quote:

wish we could do this more things in SH3, like not having to do the TDC your self, just ordering off the AOB, distance, speed, bearing excreta.

You can turn on the "Weapons Officer" or some other feature in the difficulty menu. He does all the calculations for you, if I remember correctly.

I think it's more rewarding to do it yourself though. However, and I don't mean to boast, I am finding that lining up a shot at "full difficulty" is really easy in this game. At 100% "realism" I've already sunk 8 ships in my career in a Type II (This puts me in the top 7 U-boat aces for the time period).

Sailor Steve · 03-05-12, 10:29 AM

Quote:

Originally Posted by Luno

I totally agree, but I'm just wondering if the helmsman could actually keep the sub at a specific depth if the sub wasn't moving. I don't necessarily want to do his job, I just want to know if it was necessary to keep moving to help maintain depth.

Yes it was possible, with a very good man on the pumps. Much easier today with computer controls. On the other hand it requires using the pumps, which make just as much noise as the propellors at flank speed, so even if you had a guy that good it wasn't practical. Moving at two knots is much more effective.

Luno · 03-05-12, 01:36 PM

Thanks for all the help guys. I'll be incorporating this element into my attacks from now on.

02-29-12, 06:55 PM	#1
Luno Ensign Join Date: Mar 2011 Posts: 234 Downloads: 123 Uploads: 0	Depthkeeping during attacks (?) Hi Kaleuns, I've read that it's really difficult for a sub to maintain a precise depth, and this is especially critical at periscope depth and while making attacks. Apparently, the sub had to be moving at all times in order to have enough water-flow over the dive-planes and rudder to keep the depth and heading constant. Is this a valid concern, and is there a mod which addresses this? At what speed, historically, did subs move in order to make a submerged attack? This would certainly add an interesting element to TDC calculations... __________________ Career: Feb. 13, 1942 "Cpt. Johny Goodwood" Porpoise class: USS Shark, SS-174 Patrols: 2 Victories: 1 Merchants (4519 GRT), 0 Warships (0 GRT), 0 Aircraft Sunk with all hands lost.

02-29-12, 07:39 PM	#2
PappyCain Samurai Navy Join Date: Aug 2008 Location: on the Atlantic Ocean Posts: 559 Downloads: 10 Uploads: 0	A very good question! Yes, to maintain neutral buoyancy and not use the ballast to trim constantly one had to keep the boat moving as you well state. As to speed it was slow to avoid the periscope making a noticable wake and best done with the sun at your back. That made it harder to spot too. (Side note: when a torpedo is launched, the weight of the boat had to be immediately balanced with ballast, as the launching of a torpedo caused more than a ton of positive buoyancy. If this was not offset by ballast, the boat could pop to the surface, giving away its position. Many U-boats were caught and abruptly attacked due to this simple error.) __________________ DID, no cheats, no shortcuts, no non-historic equipment deviations. Boat and crew safety is integral with my immersion style! Follow the historic events during your patrol: http://www.uboat.net/today.html

02-29-12, 08:09 PM	#3
Luno Ensign Join Date: Mar 2011 Posts: 234 Downloads: 123 Uploads: 0	The player doesn't really have control of the ballast...is the game's ballast-man just that good? (Kinda like how the weapons officer makes no mistakes if you enable him in the difficulty) Considering that the maximum periscope-up speed is about 4-5kts (due to wake and vibrations), I would image that 1-2kts is sufficient to help keep a boat at the right depth... If this is so, I may end up imposing this restriction on myself as I play __________________ Career: Feb. 13, 1942 "Cpt. Johny Goodwood" Porpoise class: USS Shark, SS-174 Patrols: 2 Victories: 1 Merchants (4519 GRT), 0 Warships (0 GRT), 0 Aircraft Sunk with all hands lost.

02-29-12, 09:33 PM	#4
Kapt Z Grey Wolf Join Date: Aug 2007 Location: ...somewhere in the swamps of Jersey. Posts: 909 Downloads: 157 Uploads: 0	I try and always stay at 2kts or below when I raise the scope. __________________ ...I fought in many guises, many names, but always me. Patton

02-29-12, 11:17 PM	#5
Sailor Steve Eternal Patrol Join Date: Nov 2002 Location: High in the mountains of Utah Posts: 50,369 Downloads: 745 Uploads: 249	NYGM has the "anti-hummingbird" mod built in. Two knots or less and you start to slowly sink. __________________ “Never do anything you can't take back.” —Rocky Russo

03-01-12, 05:12 AM	#6
Harald_Lange Ensign Join Date: Jan 2012 Location: NY Harbour, Periscope depth. Posts: 235 Downloads: 160 Uploads: 0	I usually find the track of the target , and plot a course to 5-700m off the track at 90 degrees, and sit there, periscope just under the surface, listening on my hydrophone until the angle is right, then peek and fire at the last moment. After reading this, it seems what I'm doing is wholly unrealistic.

03-01-12, 07:27 AM	#7
andwii Frogman Join Date: Sep 2011 Location: Bridge of U-123 Posts: 300 Downloads: 76 Uploads: 0	ya ive noticed on the boats like IIA that depth keeping at periscope depth is a pain if your not going more then 2 knots, which really isnt all that bad of a speed, its not to loud but it sure is loud enough to give you away in 1942-1943 lol.

03-01-12, 07:34 AM	#8
u crank Old enough to know better Join Date: Dec 2011 Location: Prince Edward Island Posts: 11,744 Downloads: 136 Uploads: 0	I have often wondered about depth keeping also in regards to realism in SH3/GWX. There are some very detailed explanations of this in Edward Young's great book 'One of Our Submarines'. http://www.amazon.co.uk/One-Submarin.../dp/1844151069 After reading those sections again I realize that this was not the Captains job. He would tell his officer in charge of this task if the sub was not at the proper depth, but he didn't actually do it himself. This is very well simulated in SH3/GWX. Your helmsman is doing his job very well. No need to yell at him. Good hunting. __________________ “Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” ― Arthur C. Clarke

03-05-12, 01:36 PM	#12
Luno Ensign Join Date: Mar 2011 Posts: 234 Downloads: 123 Uploads: 0	Thanks for all the help guys. I'll be incorporating this element into my attacks from now on. __________________ Career: Feb. 13, 1942 "Cpt. Johny Goodwood" Porpoise class: USS Shark, SS-174 Patrols: 2 Victories: 1 Merchants (4519 GRT), 0 Warships (0 GRT), 0 Aircraft Sunk with all hands lost.