Trying to stick to real life practices: What is the purpose of the daily trim dive?

Konovalov · 02-26-08, 08:15 AM

Having a great time having returned to SHIII with GWX 2.0. On my 9th patrol mid 1940 now operating out of Lorient, still using Type VIIb.

Anyway I have started reading the book Iron Coffins by Herbert A Werner and I'm trying to implement as many real life procedures and tactics as I can into my in game experience.

I have noticed in the book constant reference to 'the daily trim dive' that was performed by the U-boat while on patrol. Can someone tell me why this was done on a daily basis and what was the point of this practice?

Grayson02sept1980 · 02-26-08, 08:40 AM

I think it was a daily routine to check if everything is ok for diving; check if the depth ruder and trimming tanks/vents... whatever worked

I am by far not an expert and I know little but I am just guessing.

PhantomLord · 02-26-08, 09:57 AM

Quote:

Originally Posted by Grayson02sept1980

I think it was a daily routine to check if everything is ok for diving; check if the depth ruder and trimming tanks/vents... whatever worked

I am by far not an expert and I know little but I am just guessing.

Correct so far.

Boats behaviour under water is affected by many things

- water density and temperature - affects the amount of water to flood the tanks for a designated depth

- fuel and food consumption over the last day - it affects the weight

Chief engineer has to watch all these things and has to calibrate the boat every day. It´s all a matter of mathematics

If the boat is trimmed wrong you´ll stay too long on the surface or go deep much too fast.

PhantomLord · 02-26-08, 11:09 AM

Quote:

Originally Posted by Mikhayl

Quote:

Originally Posted by PhantomLord

Quote:

Originally Posted by Grayson02sept1980

I think it was a daily routine to check if everything is ok for diving; check if the depth ruder and trimming tanks/vents... whatever worked

I am by far not an expert and I know little but I am just guessing.

Correct so far.

Boats behaviour under water is affected by many things

- water density and temperature - affects the amount of water to flood the tanks for a designated depth

- fuel and food consumption over the last day - it affects the weight

Chief engineer has to watch all these things and has to calibrate the boat every day. It´s all a matter of mathematics

If the boat is trimmed wrong you´ll stay too long on the surface or go deep much too fast.

I'd add that if the boat isn't trimmed properly it can be "heavy" on the bow or on the stern and thus very difficult to sail underwater

Right, thanks

Jimbuna · 02-26-08, 11:26 AM

Initially it was also used as a means to check no sabotage had ocurred if the boat had been subject to shipyard maintanance.
As an example, it had been known for rope to be inserted in a seam to look like welding had been carried out.

PavelKirilovich · 02-26-08, 11:40 AM

Other common forms of sabotage were "forgetting" tools or other hard objects in the ballast tanks and other sealed spaces after maintenance. This would create noise upon diving, helping ASDIC operators.

PhantomLord · 02-26-08, 11:43 AM

...crosspost...

Yep.. some boats were lost without a clear reason. In some books i have you can read about many ways to sink a sub in the later years.
From bast shoes in the conning tower hatch, over to loose screws on the exhaust caps and flood tank caps and so on...
Afaik it was U123 (Hardegen) who returned to Lorient after one day. Boat was far away from being watertight!

flag4 · 02-28-08, 02:47 PM

Quote:

Originally Posted by jimbuna

Initially it was also used as a means to check no sabotage had ocurred if the boat had been subject to shipyard maintanance.
As an example, it had been known for rope to be inserted in a seam to look like welding had been carried out.

THAT is unbelievable - and believable too....

the people who did that sort of thing were brave beyond imaginable.

i think my only form of sabotague would be to not sweep up very well or dont empty the bins - drop litter, that sort of thing.

that example is really shocking - my god, you would test everything before heading out to sea. and then the thought of 'well, im probably not coming back anyway...'

Laufen zum Ziel · 02-26-08, 10:51 AM

For more realisim go to the below link under Authentic Photographs tab and you will see over 250 photos of U-boats and their crew, Chances are that your U-Boat will be there and is downloadable and printable. While your in that carreer you will have a photo of the actual boat and crew.

Wenn es mehr Waffen, dann laufen wie die Hölle

http://silent-hunter-addict.com

Brag · 02-26-08, 11:03 AM

Quote:

Originally Posted by Laufen zum Ziel

For more realisim go to the below link under Authentic Photographs tab and you will see over 250 photos of U-boats and their crew, Chances are that your U-Boat will be there and is downloadable and printable. While your in that carreer you will have a photo of the actual boat and crew.

Wenn es mehr Waffen, dann laufen wie die Hölle

http://silent-hunter-addict.com

That's an excellent site, I like the today in history page.

02-26-08, 08:15 AM	#1
Konovalov Ocean Warrior Join Date: Sep 2002 Location: High Wycombe, Bucks, UK Posts: 2,811 Downloads: 9 Uploads: 0	Trying to stick to real life practices: What is the purpose of the daily trim dive? Having a great time having returned to SHIII with GWX 2.0. On my 9th patrol mid 1940 now operating out of Lorient, still using Type VIIb. Anyway I have started reading the book Iron Coffins by Herbert A Werner and I'm trying to implement as many real life procedures and tactics as I can into my in game experience. I have noticed in the book constant reference to 'the daily trim dive' that was performed by the U-boat while on patrol. Can someone tell me why this was done on a daily basis and what was the point of this practice? __________________ "In a Christian context, sexuality is traditionally seen as a consequence of the Fall, but for Muslims, it is an anticipation of paradise. So I can say, I think, that I was validly converted to Islam by a teenage French Jewish nudist." Sheikh Abdul-Hakim Murad (Timothy Winter)

02-26-08, 08:40 AM	#2
Grayson02sept1980 中国水兵 Join Date: Jan 2008 Location: Germany-Bayreuth Posts: 276 Downloads: 6 Uploads: 0	I think it was a daily routine to check if everything is ok for diving; check if the depth ruder and trimming tanks/vents... whatever worked I am by far not an expert and I know little but I am just guessing. __________________ SH3 Commander GWX 2.0 OLC GUI

02-26-08, 11:26 AM	#5
Jimbuna Chief of the Boat Join Date: Feb 2006 Location: 250 metres below the surface Posts: 190,473 Downloads: 63 Uploads: 13	Initially it was also used as a means to check no sabotage had ocurred if the boat had been subject to shipyard maintanance. As an example, it had been known for rope to be inserted in a seam to look like welding had been carried out. __________________ Wise men speak because they have something to say; Fools because they have to say something. Oh my God, not again!!

02-26-08, 11:40 AM	#6
PavelKirilovich Machinist's Mate Join Date: Nov 2007 Location: Canadian Coast Posts: 123 Downloads: 28 Uploads: 0	Other common forms of sabotage were "forgetting" tools or other hard objects in the ballast tanks and other sealed spaces after maintenance. This would create noise upon diving, helping ASDIC operators. __________________ Winter Garden on the North Atlantic Currently: U128 (Type IXC), U180 (Type IXD2), U198 (Type IXD2) operating in the I.O. Previously: U48 (Type VIIB), U568 (Type VIIC) [Completed 1940-1945 career in Type VIIs, in the Atlantic] Running: SH3 v1.4b w/ GWX 2.1

02-26-08, 11:43 AM	#7
PhantomLord XO Join Date: Sep 2006 Location: Berlin, Germany Posts: 408 Downloads: 124 Uploads: 0	...crosspost... Yep.. some boats were lost without a clear reason. In some books i have you can read about many ways to sink a sub in the later years. From bast shoes in the conning tower hatch, over to loose screws on the exhaust caps and flood tank caps and so on... Afaik it was U123 (Hardegen) who returned to Lorient after one day. Boat was far away from being watertight! __________________ ~^~ War does not determine who is right - only who is left. ~^~

02-26-08, 10:51 AM	#9
Laufen zum Ziel Eternal Patrol Join Date: Jan 2008 Location: Hiding on the bottom Posts: 1,783 Downloads: 853 Uploads: 457	For more realisim go to the below link under Authentic Photographs tab and you will see over 250 photos of U-boats and their crew, Chances are that your U-Boat will be there and is downloadable and printable. While your in that carreer you will have a photo of the actual boat and crew. Wenn es mehr Waffen, dann laufen wie die Hölle http://silent-hunter-addict.com __________________ RIP Laufen zum Ziel