Question about WWII German U-boat bow planes

[Gannet]

Yesterday I was watching Stealth Submarine on NatGeoTV. It was about the U-480 which was a Type VIIC U-boat. There was a portion of the show that showed a close-up of the bow plane operating which caught my attention because forward of the bow plane was a fixed vane, which I have never notice before on any other submarine. I do not understand the reason for this fixed vane.

I search the intenet and found that this design was used on subsequent German U-boats, see attachments.

The German U-boats bow planes were not retractable like US Submarines. I am guessing this fixed vane serves some hydrodynamic function such as for surface running.

[Knut Sand]

or just protection? (for the rudder).

(If I understand your question correctly)

[tom28571]

Are you sure that it is fixed?
Looks like it might be movable to me but I'm no expert on UBoats. That arc of holes around the forward vane is interesting. Wonder what that is.

[liki]

My understanding is that they were primarily to prevent tangling in mine cables or submarine nets.

[Gannet]

Are you sure that it is fixed?
Looks like it might be movable to me but I'm no expert on UBoats. That arc of holes around the forward vane is interesting. Wonder what that is.

It appearred fixed on the show when they were showing the operation of the bow planes.

I did noticed the arc of holes on the Type IXC/40 U-boat and not sure of their function.

I think cable protection is a secondary function, because it so close to leading edge of the bow plane. Another fact I found out during my internet search was that the German U-boat's bow planes were electrically actuated instead of hydraulically actuated like the US. Maybe it is a hydrodynamic aid to reduce torque required to actuate the bow plane?

Maybe it is a fixed slat instead of movable ones like those used on fixed wing aircraft to improve lift during takeoff?

Maybe it directs the flow to be horizontal when near the wavy surface?

If it primary function is hydrodynamic, I would appreciate if someone could enlighting me on theory.

[Ad Hoc]

I'm not a sub designer, but a quick review of what the hydroplanes does help to explain, but it is also a function of the hull shape too.

Older UBoats by today's standards are slow. Fwd fins are required for slow speed only. Since the subs were predominantly slow, i am assuming that it was sensible to fix the fins attitude to save weight. Not much point adding lots of weight and more systems to go wrong and take up more internal space, when it wasn't 100% necessary.

Modern sub's for example though, have a common long.t axis, hence their frames (and hull shape) are circular. This makes the "zero fluid force" perpendicular to the direction of travel. Also, since the hull acts as an inefficient lifting surface, it is desirable to reduce the inefficiencies as much as possible. The older Uboats didn't have such luxuries, owing to the presence of the larger "bridge fin" and a not so symmetrical hull shape (by modern designs) - hence their MO was to troll about at slow speed, most efficient way is to have the fwd fins fixed.

[Squidly-Diddly]

as the rear planes weren't retractable. I heard they were for docking, but that seems like a lot of drag to haul around.

You would think once in port they could deal with it, or have a Stand-Off section of dock. Notice the guards are out the water when surfaced.


http://www.westbourne-models.com/images/Model-Boats/Revell-plastic-boat-models/Revell-Gato.jpg

[Gannet]

Older UBoats by today's standards are slow. Fwd fins are required for slow speed only. Since the subs were predominantly slow, i am assuming that it was sensible to fix the fins attitude to save weight. Not much point adding lots of weight and more systems to go wrong and take up more internal space, when it wasn't 100% necessary.

Thanks Ad Hoc for your comments; The WWII German U-boats did have moveable bow planes aft of this fixed fin. However, I found the following statement about WWI German U-boats at http://www.dreadnoughtproject.org/models/ships/SMS_UB_2/

"Rather than having movable bow diving planes, the half-spade shaped fins were fixed at a downward angle and the deck casing limber holes were more closely spaced forward of the conning tower to create a natural bow-down angle and submerge the planes immediately on opening the ballast tank vents. Forward momentum of the boat would further force the bow underwater as the propulsion was shifted from diesel to electric. The movable stern diving planes (sometime referred to as horizontal rudders by the British) were proportionally oversized as compared with the planes on larger U-boats, thereby giving sufficient control authority to adjust the attitude of the boat. The boat could be operated with a slightly positive buoyancy, and as long as the motors provided forward propulsion the fixed bow planes would keep the bow down, but if speed was decreased, the bow would naturally rise even without putting a rise on the stern planes."

Squidly-Diddly - Thanks also for your comments I have that model

[Ad Hoc]

Gannet

Having an aft and fwd fin is the only way to maintain constant depth with an even keel, since the aft and fwd fins enable the sub to find its common long.t axis.

These two fins create a vertical or rather a force perpendicular, to the long.t axis. The result force must be applied at the hydrodynamic centre of the hull, or neutral point. However for fwd motion at constant velocity the hydroplanes (fwd and aft fins) may be adjusted so that the resultant force is fwd of the neutral point.

It then gets a bit messy, as there is a location called the "critical point", call it C. This varies with the speed. At low speeds this position is well aft, at high speed it is well fwd.

At low speeds, there is a 'critical speed', below this speed C's position is abaft of the aft fin. Therefore the fwd fins are used for maximum rate of rise.

At high speed, the location of C is far fwd, hence the aft fins provide the control.

Hence having both fwd and aft fins, the hydroplane provide both trim and depth control at any speed.

As i said before, i'm not a sub designer, i design surface boats/ships. However a quick review of my old notes suggests it is not so straight fwd and is rather complex, since there are many different 'forces' acting with or against the hull in its desired motion to maintain stability.

[apex1]

The fins simply provided a lifting force at the bow. Due to the fact that the pressurized compartement was well behind the bow, there was no (or not enough) lifting force when the boat operated at the surface. But that was the standard operation mode for all submarines until the 50ies.
So, Ad Hoc got it right!

Regards
Richard

[Gannet]

Thanks Ad Hoc for the refresher on diving planes mechanics.

My question is about the Fixed Fin directly forward of the moveable bow plane, see attachment.

As I stated in previous post
I think cable protection is a secondary function, because it so close to leading edge of the bow plane. Another fact I found out during my internet search was that the German U-boat's bow planes were electrically actuated instead of hydraulically actuated like the US. Maybe it is a hydrodynamic aid to reduce torque required to actuate the bow plane?

Maybe it is a fixed slat instead of movable ones like those used on fixed wing aircraft to improve lift during takeoff?

Maybe it directs the flow to be horizontal when near the wavy surface?

[Ad Hoc]

Im not sure if you are just making a statement or asking a Q?

[Gannet]

Im not sure if you are just making a statement or asking a Q?

I am asking a question about the Fixed Fin just forward of the Moveable Bow Plane on WWII German U-boats. I have not see this arrangement on any other submarine.

I was wondering if anyone would know why the Germans would use this configuration over the normal moveable bow plane only which have been around since the Hunley.

Thanks again for your comments

[wardd]

early war u-boats had net cutters on the bow, so i would assume they were to keep the bow planes clear of obstructions and as the bow planes were not retractable they would have protected them when docked

the type XXI had retractable planes and didn't have the fixed protrusions

[Squidly-Diddly]

Ad Hoc: All the sub novels I've read include lots of references to trimming the ballast tanks(fore and aft) after all sorts of events(launching torpedoes, etc) and that even minor out of balance becomes noticeable (although it can be corrected with movable planes). Sort of like you CAN force a car to go in a straight line with the steering wheel even if the front-end(or rear end) has been smacked way out of whack in an accident.

Any overall trim imbalance of even very small amounts would cause the sub to sink or rise. Almost all the submarining was done with very minor trim adjustments rather than the planes except for diving and surfacing or dodging depth charges.


Apex: Are you saying that when a U-boat was under way on the surface it needed the bow planes to keep the bow up? Never heard that one. I'm sure you could remove the bow planes and the boat would cruise on the surface just fine, as their hull shape is very similar to American subs that cruised with bow planes retracted.

I'm pretty sure you could remove either bow or stern planes, or both, and just use fore and aft trim tanks for everything and you would only lose a little quickness in diving or surfacing or otherwise changing depth.

[apex1]

Thanks Ad Hoc for the refresher on diving planes mechanics.
My question is about the Fixed Fin directly forward of the moveable bow plane, see attachment.
As I stated in previous post

I was referring to the FIXED part only!

And the reason is NOT mainly related to net preventing. At least the information at the U 995 a Type IIV C boat in Kiel Laboe says so. That info board was made by ex crew, so I assume that it is correct.

Regards
Richard
http://upload.wikimedia.org/wikipedia/de/8/82/U995_0.jpg

[Squidly-Diddly]

U-boats with only two tubes, not what is normally thought of as a U-boat such as Type-VII, which had moveable planes fore and aft, with guards on both.

You can see aft guards on Apex's pic, they also guard the prop.

[Submarine Tom]

Gannet,

Great post, thanks.

Just an idea, but why not ask the poster who prompted your question?

I don't know the definitive answer to your question but I'm going with

protection, hydrodynamic aid (sometimes a benefit can be had by "slatting"

in front of a hydroplane), trim capability (you thought they might have been

adjustable), stability (snap roll) and perhaps even redundancy to some

extent. That's all I can think of right now.

apex1: Where is the beach photo from, do you know?

Tom

[Ad Hoc]

It does indeed seem logical that they are guards of some type. Since they are some distance fwd of what is the leading edge of the fin, hence the lift contribution is negligible., other than itself as a lifting surface, since planar.

The use of ballast, is ostensibly for getting down to the depths, by making her 'heavy', or getting to the surface, by making her buoyant. The secondary function is to alter/correct the CoG. The location of the CoG is very important and affects the forward motion and as such influences the effects of the hydroplanes.

The hydroplanes, provide heave and pitch control. They cannot alter the CoG, nor make the sub more or less buoyant for rapid rise and/or descent.

You must remember that a sub, unlike a torpedo, is not axially symmetrical. Consequently the sub has both a force and moment acting upon it about its CoG. Hence these perturbations, vertical, heave, and angular, pitch, are controlled by the hydroplanes.

[wardd]

they would have the crew run forward and pitch the forward planes down and use the screws to drive the boat down

[JohnTT]

Knowing nothing about subs but something about sailboats, the VIIC drawing seems to be not really meant as a fin but as a streamlined skeg to support the diving plane. Just like a traditional skeg hung rudder on a sailboat, this would allow a smaller shaft, simpler bearings, and much less reinforcement at the inboard bearing.

The planes also look to have a long chord and be set very close to the hull - even a tiny flexing of the shaft would jam the plane. Perhaps the close fitting to the hull is intended to create an end plate effect to improve the plane's lift.

I've experienced a jammed rudder when a sailboat's spade rudder was bent by a collision with a log. I would expect that a jammed diving plane would be even less fun.

John

[JLIMA]

Having served on submarines, albeit US nuclear missile subs the only thing those projections could be is what John said they are, something similar to a protective skeg, they are to small to have an effect on handling at the submerged speeds at which these boats were capable of (less than 7 knts usually, although some later types could get up to 12) so the actual plane surface angle would have more effect on the attitude of the boat. Even on the boats i'm used to we would only switch to the stern planes when doing "high speed operations" because it would become to easy to over plane at the higher speeds with the bow planes causing a depth excursion. Considering the speeds these boats opperated they would use both bow and stern planes to maintain depth and attitude (bow planes to maintain depth and stern planes to maintain the boats angle).

[Gannet]

Thank you everyone for your comments

As mentioned by JohnTT, on the Type VIIC U-Boat the fixed fin provided bow plane shaft support, see attachment. However, it is my opinion that this is secondary function because if you look at the Type IXC/40 and Type XXIII it is clearly seen that there is no attachment between the fixed fin and the moveable bow plane.

One thing I notice between German U-Boats and the US & British Submarines is that the bow plane waterline for German U-Boat is lower than the others. In other words, even when running on the surface they would be submerged and therefore would be effective as soon as they were inclined. A thought I am having is that moveable bow plane without a fixed fin would be an abrupt transition whereas with the fixed fin it would be a smooth transition. An abrupt transition would increase the likelihood of over or under control.

Thanks Apex 1 for the great photo and what was written by the crew about the fixed fin primary function not being net preventing.

I wonder if any of the Allies during the war analyzed the German approach.

[bntii]

Gannet- you must have been to visit the USS Torsk by now?

http://www.usstorsk.org/history/423lnch.jpg

I find this passage in G. Williamsons Wolf Pack - The Story of the U-Boat in World War II on use of the forward bow planes:

"Once at the required depth below the surface, the boat would level off and hydroplanes would be used to keep the boat stable and stop it from rising to the surface. U-boats normally had a slightly negative trim, so that if fully stopped they would slowly sink. In order to stay at the required depth, some forward movement was therefore needed and this, in conjunction with skilled use of the hydroplanes, kept the boat level. Although compressed air could shift water fore and aft between bow and stern trim tanks to adjust the balance of the vessel, the simple expedient of moving unoccupied crew members from one end of the boat to the other was often used instead."
http://www.scribd.com/doc/13729308/Wolf-Pack-The-Story-of-the-UBoat-in-World-War-II
This title has many period photos of all aspects of the program.

From what I am seeing the definitive treatise is Rossler's

The U-Boat: The Evolution and Technical History of German Submarines
Expensive...

I think I am gathering correctly that the more important design difference between the two forces is the upper placement of Allied craft compared to the low fins of the German ships?
Functionally the higher planes are not submerged when run on top.

More history this thread- fascinating though also tragic..:

"The attrition rate of somewhere between 70 and 80 per cent is the highest casualty rate of any of the armed services in any of the combatant nations of World War II."

and the "Laconia Order" (http://www.uboat.net/ops/laconia.htm)[/URL]

[Ad Hoc]

Gannet

Another, in hindsight, rather obvious reason for the fixed "fins" is that image the sub coming along side her berth. It wouldn't be parallel, it would be slightly off, hence the bow would come in first. As such, how does the Capt. know where the ends of the fins are?....the fixed "fins", or rather guards, do just that. Protect the fins from damage when coming along side.

[apex1]

apex1: Where is the beach photo from, do you know?
Tom

Tom there is some text at the picture!!! How would I know about the info board?........:idea:


bntii
got the right hint too: U-boats normally had a slightly negative trim in case of the German boats that was a pretty noticeable one. As I mentioned above, the bow had no buoyancy, the fixed fin provided a lifting force at the usual surface operation speeds around 10 to 12 kn. The "Tiefenruder" exactly translated "depth control rudder" (what you call plane here), was out of duty at surface.

Thats all I know from a visit in the late 70ies and some talks with former crew.

Regards
Richard

[wardd]

Authority

The design studies, of which this report is a part, have been made under the authority of the Chief of Naval Operations restricted letter Op-23C-1-Serial 217423 of 28 May, 1945. This letter directs the Naval Shipyard, Portsmouth, to prepare design studies, perform tests and to compile reports on each type of submarine.

The bow plane guards are relatively heavy horns which are of streamlined section, and extend out and aft away from the hull in a horizontal plane forward of the bow planes, with the extreme end of the horn outboard of the outer edge of the plane, on the axis of the plane shaft. There is no connection between the outer edge of the plane and the end of the horn.

http://www.uboatarchive.net/DesignStudiesTypeIXC.htm

http://www.uboatarchive.net/index.html

[Submarine Tom]

Richard,

I see no "text at the picture". What info board do you speak of?

I simply asked "Where is the beach photo from, do you know?"

Is it from your personal collection, the Internet, if so where.

I'm sorry if this is too taxing a question for you but I think it reasonable to

ask. Do you know where the photo was taken? Do you know what ship it

is? Let me try and simplify it for you:

Do you have any further information on the photo you posted.

Thanking you in advance for your response regardless of how defensive it

may be.

Tom

[apex1]

Richard,
I see no "text at the picture". What info board do you speak of?
Tom

Hello Tom, no need to loose your good manners.;)

there is a text above my picture saying that the boat is in Laboe! That is near Kiel (Kieler Woche, Volvo Ocean Race) in northern Germany.
The boat is open to the public and there is a info board aboard (thats two boards).
And the rest was all in my post above the picture! And still is!

I´m not defensive!
Sometimes it would be good to remember that many of the contributors here are not native English speakers, and we are fiddling here with complex subjects (well not in every thread).
Some need about five times longer to type (and often retype) a text than average joe, though their educational level is ten times higher than his!

Hope I could answer your questions sufficiently.

Regards
Richard

[Submarine Tom]

Richard,

Now I understand, thank you for clarifying.

Regards,
Tom

[Gannet]

wardd Great discovery. I going to review it now and probably be back with more comments.

bntii - Have not been to the Torsk yet, but now that I am retired it will give me something to do. I have been to the Submarine Muesem in Pearl Harbor. Also, The Wolf Pack Book how big is the downloaded pdf?

I have been going through all my Submarine Books.

The following are applicable excerpts on diving planes and bow planes from Friedman, Norman; Submarine Design and Development; Conway Maritime; London; 1984:

Diving planes perform three very different functions; diving, surfacing, and depth and trim control. The latter must be quite precise at or near periscope depth.
At greater depths, it is more important for maneuvering, so that the rate of changing depth is more important than the ability to maintain a particular depth.
Bow planes were initially added to permit submarines to dive on an even keel, although that has not been the standard practice for many decades.
Bow planes located underwater (when the submarine was fully surfaced) would be effective as soon as they were inclined, and so would (in theory) make for fast submergence, but they were also a source of resistance, making for reduced surface speed. Planes above the waterline would not slow a submarine, but they would not take effect until it reached the awash condition; i.e., until some considerable flooding had occurred.
Bow planes were also notoriously subject to damage when coming alongside or docking. One compromise was folding planes employed by many navies. However, it was argued that the extra mechanism increase their chance of failure.

[bntii]

Good morning Gannet,

I see you are in Baltimore, MD. I am just down the road in DC. I had a chance to board the Torsk some years back.

I don't know how large the download is. I reviewed the text in the on-line browser & the download is limited to members. Do you have a copy of Rossler's book?

Yeah- that site wardd posted is remarkable.
I spent some time going over the accounts & period photos.

http://www.uboatarchive.net/U-595JuniorEnlisted.jpg

Some happy faces among these German kids captured after their sub was destroyed. No surprise given how rare it was to have survived.

[Gannet]

Yes I am right up I-95 from you. Lived here all my life except when I was in the Marine Corp and when I was Marine Engineer on a Merchant.

I am member of Scibd, when I tried to download the pdf it was up to 30 Meg when I got a runtime error.

I remember reading that 4 out of 5 German U-boat sailors perish during WWII.

I don't have Rossler's book.

I have been reviewing the design study and the statement they make in it "complete entity present little of interest" does not sit well with me. I hope they were not "jumping to conclusions." But as wardd mentions it does call what I've been calling "fixed fins," "Plane guards for bow planes."

Also apex 1, I notice that at the site wardd provided http://www.uboatarchive.net/index.html
they are looking for translators. IMHO you would be ideal

Another thought I was having is that having the bow planes always underwater even when on the surface provided any hydrodynamic lift like hydrofoils to reduce wetted area.

I really enjoy this discussion it is nautical, technical, and historical:)

[wardd]

also having the planes fixed eliminated some complexity and expense and as the type vii was small, space and weight

http://www.navweaps.com/index_tech/index_tech.htm

is full of neat info

[Submarine Tom]

I toured the HMCS VICTORIA in dry dock last week.

www.naval-technology.com/projects/ssk_victoria/

She has retractable (not folding) bow planes. They are surpisingly small

and not used very often. They would be submerged while surfaced.

Tom

[apex1]

I remember reading that 4 out of 5 German U-boat sailors perish during WWII.

That is true....


Also apex 1, I notice that at the site wardd provided http://www.uboatarchive.net/index.html
they are looking for translators. IMHO you would be ideal

Thank you for the flowers, but, no thank you. Being abroad for 8 month a year or more, I´ve lost my knowledge of the English (and German) language almost completely. I would have to stay in GB for some month to do that.



I really enjoy this discussion it is nautical, technical, and historical:)

Me too.

[Gannet]

Wardd still going through the design study you found and also the other index which has an article on the "The Working Environment for German Submarine Design in WWII" You are like a hound dog finding these great sites!

One thing I noticed in the design study is that on the Type IXC-40 the bow planes are rigged at a 7 degree rise (design was for a 5 degree rise) and because it is submerged while the submarine is running on the surface would provide lift such that it would reduced wetted area. I am thinking that the reduction in skin friction drag maybe significant enough to offset the drag associated with the bow plane being submerged.

Another thing I noticed in the report is that all the control surfaces: rudders, stern planes, and bow planes were electrically actuated.

Also there is mentioned "Further with respect to rudders, the vertical center of area is relatively higher on the vessel than it is in current U.S. Naval practice, thereby reducing the tendency for the vessel to take a list when turning." I am also thinking that having the bow planes permanently rigged also reduces this listing during turns

Submarine Tom She has retractable (not folding) bow planes. They are surpisingly small and not used very often.

From Friedman, Norman; Submarine Design and Development; Conway Maritime; London; 1984; p124 he states:
Bow planes far forward provide a more effective movement for low speed control when submerged and can therefore be made smaller to reduce drag. To further reduce drag, and noise, at high speed they can be retracted - at a cost in mechanical complexity. Paradoxically, at high speed they need to be kept extended if they are to counteract any stern plane jam. This is a captain's decision, depending upon the circumstances.

Apex1 The only people I give flowers to are the wife or dead people. I was just bringing it to your attention.

Thanks again

[apex1]

Apex1 The only people I give flowers to are the wife or dead people. I was just bringing it to your attention.Thanks again

You ruined my day. :mad:
I was so happy I´ve given the right explanation and to receive a bunch of pansies.
And then that...............

[Knut Sand]

About history;

ships:
In many instances; sunk by submarine and type/ date.

http://www.warsailors.com/search.html


Submarines:

http://uboat.net/index.html

[wardd]

people often get caught up in the weapon itself as though it acted alone

case in point was the panther and tiger tanks, yes they were big and mean but that brought on a whole set of problems such as getting them to the battlefield and being so expensive and labor intensive that few were built

same as for subs the Germans had the wrong equipment for the second half of the war for the area of combat and the enemy's capabilities where as the american subs succeeded against the Japanese because the had the right mix of capabilities for their environment

[apex1]

case in point was the panther and tiger tanks, yes they were big and mean but that brought on a whole set of problems such as getting them to the battlefield and being so expensive and labor intensive that few were built

same as for subs the Germans had the wrong equipment for the second half of the war for the area of combat and the enemy's capabilities where as the american subs succeeded against the Japanese because the had the right mix of capabilities for their environment

The Tiger Tank was too heavy and overly complicated to be a good tank. Thats true, but the Panther was far better. The Tiger was designed by Ferdinand Porsche btw.

The Type VII boats were almost a perfect weapon (far better than any allied sub) but the German Admirality did not understand some problems.

1- The tactic was deadly:
the so named "wolf- pack" tactic required a radio signal sent by the first boat in contact with a target (mainly convoy), to bring more boats in contact. These signals were easily located by British and US forces and the "surprising moment" was gone gone. Quite often this first boat was attacked and scuttled.
But there was no possible solution, due to the fact that the "Luftwaffe" had no (or no sufficient) control over the most important area in the North Atlantic.

2- The lack of understanding the abilities of Radar.
Though the technology was used by themselves (and in the years 1937 `til 39 the German "Radar" was even better than the British), the German Military did not understand that it could be possible to "see" a target as small as a periscope! They did not get it until the war was over.
So, many boats have been far away from being invisible.

3- The German Enigma code was cracked in Bletchley Park after the British forces had brought up a damaged U-boat and salvaged the Enigma machine. From that day on, almost all German Navy operations were well known by the Allied forces.

4- Last: the sheer amount of Allied battleships was by far too much to make most of the attacks "successful", from 1943 on.

The situation in the Pacific was a completely different one.

Regards
Richard

[wardd]

i see the weapon as part of a system, if any part of the system is deficient then you are not going to get the best out of the weapon.

radar as a point, no matter how good the sub was with out good radar and radar detection they went to the bottom despite the quality.

the ability of the allies to pinpoint the location of uboat radio transmissions no matter how short the burst was is another point that negated the quality of the build

failure of the high command to take corrective action in the face of mounting loses negated build quality

the type xxi while being innovative wasn't really technology that couldn't have been introduced earlier, but the attitude that the war wouldn't last that long came back to bite Germany in the ass.

all these and probably more canceled out the quality of the build

the Sherman tank was inferior in its weapon and armor and had mistakes made during the design phase , in that it was thought a high velocity gun would wear out too fast, they didnt grasp the fact that the tank wouldnt last that long in combat anyway, but the big advantage of the sherman was automotive quality (it was highly reliable) it was cheap and many thousands were made and shermans could be replaced from the supply chain, while late in the war they were waiting for tigers being repaired to put back into combat, they couldnt make enough

[Gannet]

More history this thread- fascinating though also tragic..:
[COLOR="DarkRed"]
"The attrition rate of somewhere between 70 and 80 per cent is the highest casualty rate of any of the armed services in any of the combatant nations of World War II."


From http://www.navy.mil/navydata/cno/n87/history/fullhist.html
Out of 16,000 submariners, the force lost 375 officer and 3,131 enlisted men in fifty-two submarines, the lowest casualty rate of any combatant submarine service on any side in the 1939-1945 conflict.

I am thinking the main reason for this disparity in casulties ratios is because the Germans U-boats were up against American, British, and Canadian Allied Forces whereas, the United States in the Pacific were only against the Japanese. Also, the Pacific battlespace was immensely larger than the Atlantic battlespace.

[wardd]

From http://www.navy.mil/navydata/cno/n87/history/fullhist.html


I am thinking the main reason for this disparity in casulties ratios is because the Germans U-boats were up against American, British, and Canadian Allied Forces whereas, the United States in the Pacific were only against the Japanese. Also, the Pacific battlespace was immensely larger than the Atlantic battlespace.

the best weapon for the environment isn't always the best weapon technically possible

and contrary to what some believe the Japanese military wasn't on par with the then modern western militarys , they were just better prepared at the beginning of the war

[apex1]

I am thinking the main reason for this disparity in casulties ratios is because the Germans U-boats were up against American, British, and Canadian Allied Forces whereas, the United States in the Pacific were only against the Japanese. Also, the Pacific battlespace was immensely larger than the Atlantic battlespace.

Do´nt forget there have been just very few allied submarines in the Atlantic, operating as excessive (in terms of sea days) as the Germans.
Then, the war was half won when the US entered!
Other than the German U boot bases, the US and Canadian were not under aircraft attack!
And there has been no tonnage battle (convoy´s) in the Pacific.

That makes some statistics become quite clearer.

And of course, wardd, weapon is a system, not just the "gun" and the system on the German side had one major fault from 1936 on, Hitler!!! He did not leave his generals decide, he was the superior leader in his idiotic sight, and every single one of his decisions was wrong.
One can say in all seriousness, that Hitler alone has lost that war. (which was´nt to win anyway after the hughe economy of the US became part of it)
That started in Dunkerque and ended in a storm of fear, blood, steel and violence in Dresden and Ostpreussen 1945.................

The Sherman tank btw was really scrap, a lousy car. If there would have been a serious opponent and not one already conquered, I doubt one would have survived. The Russian T34 was a real enemy for the German tanks, due to his extreme robustness.

Sorry for the aside, there was not really any relation to the "fins".:rolleyes:

Regards
Richard

[Gannet]

I just searched history in Title and there's very few threads that have history in the Title

My opinion is that Design is to fill a need which is usually a result of History.

I thinking about proposing to the administrators a Nautical & Naval History Sub-Forum.

[wardd]

The Sherman tank btw was really scrap, a lousy car. If there would have been a serious opponent and not one already conquered, I doubt one would have survived. The Russian T34 was a real enemy for the German tanks, due to his extreme robustness.


Regards
Richard

i admit the sherman was not the equal of the panther or tiger and the loss rate was say 3-4 to 1 in favor of the german tanks in tank on tank combat bu the 4th or 5th sherman would prevail, there were simply so many of the damn things

but i dare say that probably most german tanks were lost to air attack


i bet most generals and admirals like playing soldier and don't want their toys broken in some nasty war, there are exception i know

[apex1]

Nice idea Gannet!

[apex1]

probably most german tanks were lost to air attack


Most were just blown by own crew! Not enough spare parts, no fuel, no ammunition.
When the US troops were in combat with the Germans the war was completely over, there was nothing to win for the Reich. Except a honorable surrender, but that was refused by the allied.
That your guys got the hide spanked in the last battle in the Ardennes was a nonsense from a tactical point of view. And it weakened the russian front.
But of course it has shown what would have happened if, say, that would have been one or two years earlier! You would have lost millions of soldiers, as the Soviet did.
Do´nt get me wrong please, I´m not a Nazi, quite the opposite! But both world wars i´ve studied in deep for some 25 years or so. And I started to study what the British and Dutch authors said, before I had the hand on German material.

Regards
Richard

[bntii]

Amazing that fisticuffs are still possible- coming on 70 years later...

[wardd]

1 person subduing 10, a problem

10 people subduing 100, good possibility

100,000 people subduing 1,000,000 no problem

[apex1]

Agreed Richard,

I subtract the statements - you understand the reason for them.

We should delete all our last posts I think, it gets a bit irritating for others.
And I would like to focus more on technical questions. Though quite often a political background has to be understood in correlation to tech. questions.
And be sure, I´m not pro or contra any of the parties involved. I have a father with British roots and a German mother. No, no predecessors from Russia or the US............:D

[wardd]

http://www.combinedfleet.com/kaigun.htm

[Knut Sand]

And I would like to focus more on technical questions. Though quite often a political background has to be understood in correlation to tech. questions.

War is politics in action, sort of... A history teacher asked my class once;

"Name technical improvements that have changed the world"
The class said;
wheel
bow/arrow (hunting)
fire
bronze
iron
plough
Then he asked what have been used in war (he was i bit into warhistory...)
We excluded only the last one (the plough, a bit impractical, but possible).
Then he asked is there somewhere a minor (another) thing/ improvement that we normally don't consider to be that useful that it can't really matter, but when thinking closer, it will?

We were tired, lazy, wanted home....

Then he said; Stirrups. (as an example).

I've never forgotten that one.... the difference that detail makes in "a political discussion"... Small difference, but may cause a change in leaders.... History is full of those small details...

[wardd]

war is that last argument of kings

[apex1]

War is the father of all things...............Heraklit
„Πόλεμος πάντων μὲν πατήρ ἐστι.“
Polemos pantōn men patēr esti.

Though that is misquoted since centuries, because Heraklit said not "war" he said "dispute", "aggro".

And the plough, at least figuratively, IS a weapon. No food, no fight.

Thanks for the contribution mate!

Richard

[Gannet]

War is the father of all things...............Heraklit
„Πόλεμος πάντων μὲν πατήρ ἐστι.“
Polemos pantōn men patēr esti.
Though that is misquoted since centuries, because Heraklit said not "war" he said "dispute", "aggro".
And the plough, at least figuratively, IS a weapon. No food, no fight.

And what I learned in the Marine Corps:
"anything can be used as a weapon"
"war is hell"
"the first casualty in war is the truth"
"everything is fair in hand-in-hand combat"
"make the enemy die for their country"
And what we said in Vietnam "the unwilling being led by the unqualified to do the unnecessary for the ungrateful."

Any thoughts on the use of bow planes as hydrofoils?

[Submarine Tom]

I don't understand the question Gannet.

Dive planes are hydrofoils aren't they?

Mine are...

Tom

[Gannet]

I don't understand the question Gannet.

Dive planes are hydrofoils aren't they?

Mine are...

Tom

Hi Submarine Tom

One thing I did notice is the German WWII submarines had their bow planes always submerged even when the sub was surfaced; whereas, the US and British submarines bow planes were either at the waterline or above the waterline when not retracted. From what I had read this was done by the US and British to reduce drag while running on the surface.

I was referring to my thoughts back in Post #33

Another thought I was having is that having the bow planes always underwater even when on the surface provided any hydrodynamic lift like hydrofoils to reduce wetted area.

And what I stated Post #37

One thing I noticed in the design study is that on the Type IXC-40 the bow planes are rigged at a 7 degree rise (design was for a 5 degree rise) and because it is submerged while the submarine is running on the surface would provide lift such that it would reduced wetted area. I am thinking that the reduction in skin friction drag maybe significant enough to offset the drag associated with the bow plane being submerged.

[Submarine Tom]

The bow planes I saw last week on our British made subs are just below

the surface and they're small. Not a lot of lift from them. This sub is

about 20 years old and about 70 meters long.

I think the idea an interesting one but consider the wetted surface area

(both sides) and the drag of a plane large enough to produce enough lift at

a drag inducing angle compared to the reduction in wetted hull area due to

raising the sub up out of the water.

I'm not convinced the cost / benefit is advantageous...

Tom

[apex1]

One thing I did notice is the German WWII submarines had their bow planes always submerged even when the sub was surfaced; whereas, the US and British submarines bow planes were either at the waterline or above the waterline when not retracted.

As mentioned already, the fixed fin had to produce lift when surfaced.
As far as I know the British and US boats had not such a sharp bow (less buoyancy), as the German boats.
Apart from that, I think the fin below WL was the better idea anyway, due to the much faster reaction when diving.

[wardd]

us subs had to range the pacific and the added drag of the planes would have cost fuel

[apex1]

us subs had to range the pacific and the added drag of the planes would have cost fuel

That should be valid for the German boats and the Atlantic too. But diving fast was the more important feature than some 0,2 kn better speed.