Aktungbby
12-24-20, 08:04 PM
I second this advise. You'll survive much longer.
Good Hunting,
FUBAR295
Not sure how historical always being decks awash is fwiw. Iirc decks awash was actually only done via e-motors ? If so, running awash always would drain them.
If not, then a waste of fuel via the added drag. The tactic was used only at very slow speeds during an attack scenario I believe vs. all the time/high speed.
I believe they never navigate Long distances deck a washed.
It might be just impossible...
Never read any sort of thing. Only for approaching convoys.Probably so; I used Decks awash to mean 1 meter high to still use the UZO and run on diesels In SH V. The sole object is to hasten the divetime in Scapa type scenarios. U-108, commanded by Knights Cross recipient Klaus Scholz, occasionally ran at decks awash:arrgh!:: https://i.pinimg.com/736x/17/b0/95/17b095f0c1276608096d7255d765cda5--german-submarines-decks.jpg Some interesting reading from 2009 for SH IV: DECKS AWASH (DA), as used here, means to operate at the deepest depth that the diesels will run continuously . The advantage in doing this is that, when compared to being fully surfaced, much less time is needed to disappear below the waves. If a threat appears, go to DA early and avoid being pounded (or sunk) as you wait, and wait, and wait, to submerge.
Running DA is mainly useful to avoid air threats. If battery recharging is critical and aircraft might be near you can safely recharge until the aircraft are spotted before quickly diving. Or, if you have radar, you can surface to DA and check for enemy aircraft before coming completely up with the comfort that if aircraft are present, they can still be avoided with a quick dive. With practice you will find other times DA is a lifesaver (rescuing downed airmen with enemy guns nearby, etc).
Two important points must be remembered, to use DA successfully. First, the critical depth for running at DA is often different between classes of submarine. Second, the critical depth for the diesels is usually deeper than that for CO2/O2 exchange and using the deck gun. This means CO2 can build up inside the sub. So there is a second DA to remember, DA(CO2). It, too, varies between sub classes but as a rule, it's 2-3 feet less than DA (diesel). DA(CO2) is always the same as the critical depth for using the deck gun, or DA(Gun), so the two can be combined.
Below is a guideline which lists the critical depths for DA(diesel) and DA(CO2/Gun) for the different classes of sub in SH4. [Measurements were made at flank speed, in calm seas, with 100% battery charge.]
DECKS AWASH DEPTH IN FEET FOR SUB TYPES
TYPE BOAT.........DA(diesel)........DA(CO2/GUN)
GATO.....................28...................26
BALAO....................28...................26
GAR.......................32...................26
PORPOISE...............28...................23
SALMON.................31...................26
NARWHAL...............30...................28
TAMBOR.................33...................25
SARGO...................31...................28
S-42......................26...................26
S-18......................26...................26
As a rule, 28 feet is a good rough guide for DA(diesel) (unless you're in an "S" boat or "TAMBOR", where it's 25 to 26). "SALMON", and "NARWHAL" classes can run slightly deeper (about 30). "GAR" and "TAMBOR" can do 32 feet.
For DA(CO2/Gun), 26 feet is a good guide for getting rid of CO2 for all boats except the "PORPOISE" class, where you must be at 23 feet, and the "NARWHAL", "TAMBOR", and "SARGO" classes, where it's 28.
The time needed to reach periscope depth is affected by 1) the depth at which the "dive" order is given, 2) the dive depth ordered ("periscope depth" vs "CRASH DIVE!"). "CRASH DIVE!" is always faster. But to avoid suicide, remember that ordering "CRASH DIVE!" takes you to 160 feet. Without that much water under you, you will die, unless you can successfully change the order (after submerging) before hitting bottom. Use "CRASH DIVE!" with caution.
Below are dive times (in seconds) between classes of boats for the order "periscope depth", fully surfaced and at DA(diesel). Times to reach periscope depth on ordering "CRASH DIVE!" will be faster. [Times were obtained at flank speed, in calm seas, with 100% battery charge.]
TIME TO REACH PERISCOPE DEPTH
TYPE BOAT......SURFACED............DA(diesel)
GATO..................120....................32
BALAO..................80.....................29
GAR....................120.....................23
PORPOISE.............85.....................24
SALMON..............107.....................26
NARWHAL............125.....................24
TAMBOR...............123....................26
SARGO.................123....................24
S-42....................72.....................47
S-18....................72.....................47
The difference between dive times is dramatic, and clearly shows the advantage of running at decks awash when a fast dive is important. It should be remembered that the DA strategy for recharging doesn't work in rough seas, where the electric engines will cut on and off, discharging the batteries.
Also remember that you get poor fuel efficiency (fewer MPG) and lower speed when running at Decks Awash since you are, after all, partly submerged.
(Incidentally, "CRASH DIVE!" from DA(diesel) will reach periscope depth for all boat classes in 17 seconds, except the "TAMBOR" class which makes it in just 15. Now that's a fast dive!)
Practical Tips:
To get to a specific depth, use the shallow depth meter (the one with the red needle at periscope depth), put the point of the cursor over the where tick mark should be for the desired depth, and left click the mouse. The "new depth" order will appear in the notification window at top of screen. (A voice will state the "new depth" order too, but often it isn't the same depth as you see printed in the window. ALWAYS go by what's in the window.) You may find the "new depth" you see ordered is not the one you thought you clicked on. If so, just do it again, this time pointing the cursor a tiny bit deeper/shallower on the depth meter from before, and notice the result. Keep doing this in tiny changes until you get the feel of it. Once you do, you should be able to "dial in" 26 feet and get it, or at least within a foot either way.
Again, to successfully run at Decks Awash you must have a sea-state that allows you to maintain constant depth, since you're running the diesels at (or near) the lowest depth they can get air. Boat speed also affects depth control. Faster is steadier.
Overall, it's probably safer to not push the limit, depth-wise, in using DA as a strategy. Give yourself a margin of error. Dive times should not be much affected.
Use the numbers as a guide and remember, they are based on the depth you see ordered as "new depth" in the notification window (top of screen). The depth seen at the bottom right of the controls (next to the "+" of Time Compression) is usually NOT what you dialed in, neither is the audio "new depth".
Versions:
This study was made using Silent Hunter4 (1.4). The later SH4 (1.5) data may, or not be different, but the concept is the same. Modding to Trigger Maru Overhaul (TMO) does not change the depths for DA, but dive time measurements from full surface ARE faster in TMO. But in all cases, starting from DA gives you a much quicker dive.
https://www.uboat.net/allies/documents/usaaf_asw3.htm Perhaps the most important task of the 1st SeaSearch Attack Group was to develop techniques for using Airborne Surface Vessel Detection (ASV) radar to find surfaced submarines. The radar that eventually went into production was 10centimeter wave equipment, known as ASV10. The British had developed a long wave ASV radar and used it to find submarines in 19411942. As early as March 1942, the I Bomber Command had four B-18's outfitted with the long wave radar sets, but the Germans outfitted their submarines with a long wave radar detector that effectively countered the British radar. The United States quickly developed the microwave radar, which the Germans never effectively countered. The first microwave sets were hand manufactured and delivered to the 1st SeaSearch Attack Group in June 1942. By February 1943, a skilled radar operator could identify surfaced submarines at more than 40 miles (64 km) and even the conning tower of a boat running decks awash at 15 to 30 miles (24 to 48 km). I rest my case::D if Uboat.net is even discussing decks awash...then somebody musta did decks awash!!!:arrgh!: platform is a platform... and a B-24 Liberator with 10 centimeter radar and four depth charges set shallow or even an outdated Swordfish torpedo plane(crippled Bismark) is a better platform. https://www.uboat.net/media/allies/aircraft/b24-2.jpg Bad Guy #1- my late uncle (just died 3 months ago; age 95) flew these bad boys!
Aktungbby
12-25-20, 02:06 AM
I use decks awash when the sea is smooth or calm and only during daylight hours and only early war up to early 1942. After that not so much.
Interestingly, I found no mention of decks wash in the Uboat Commanders Handbook, so not sure how often it was used in real life.
Good hunting,
FUBAR295Neither did I and I've spent Christmas eve looking! THe 1943 edition when Germany knew it's Atlantic war effort was not keeping up: https://maritime.org/doc/uboat/index.htm 1.) In war, only submarine commanders who possess distinctive tactical knowledge and ability will be successful in the long run. In order, however, to understand and master the tactics (i.e., of submarine warfare), it is necessary to be thoroughly familiar with the weapon, and its characteristics and peculiarities; for it is on these that the tactics depend.
In addition, complete success as a result of a thorough exploitation of the possibilities of the weapon can only be achieved if all the officers in charge of it are trained to think along the same tactical lines.
The theoretical knowledge of the weapon, and of the appropriate tactics, must be supplemented, in the last resort, by the decisive requirement of a war-like spirit and an audacious outlook. The essence of submarine warfare is the offensive! For the commander of a submarine, therefore, the maxim: "He who wants to be victorious on the sea must always attack!" has special meaning.
2.) The following instructions, in which the experiences gained in the present war have been used, are concerned with the characteristics and uses of the submarines at present at our disposal, namely of submarines for torpedo attack.
The formulation of tactical rules for other types of submarines (artillery-carrying submarines, mine-laying submarines) will only be possible when some experience has been gained of these types of vessel.
Section
General
A. Essential Characteristics and Uses of the Submarine.
3.) The chief characteristic and strength of the submarine is its invisibility due to its ability to submerge. As a consequence, the submarine is distinguished, at the same time, by another special feature, the advantage of surprise.
4.) The characteristic of invisibility serves both as a means of attack and a means of protection, and thus forms the basis for the naval use and suitability of the submarine:
a) The underwater torpedo attack without warning, in daylight and on light nights during a full moon,
b) The underwater night torpedo attack
c) The gunnery action and bombardment at night (only directed against unescorted single vessels in remote sea areas),
d) the laying of mines (undetected),
e) in short, the carrying out of independent operations in parts of the sea dominated by the enemy, where our own surface ships cannot operate.
5.) The most important naval task of our existing type of submarine is the undetected torpedo attack. This task imposes the upper limits of the size of the submarine on the one hand because of the need for good general maneuverability, and on the other - having regard to the requirements of underwater warfare because of the need for easy steering below the surface. In contrast to other types of naval vessels, it is therefore not necessary to increase the size of submarines, to give them superiority over enemy vessels of the same category, since the attacks of submarines are directed against surface ships, usually much more powerful, whose offensive power is applied in a different way.
6.) If the size of the submarine is increased above these limits, in order, for example, to substitute for its proper use a greater suitability for minor (additional) operations, such as gunnery operations, its underwater fighting power is proportionately reduced. In that case, the ability of the submarine to go below the surface serves only as a protective measure, to enable it to evade the counteraction of the enemy.
7.) Compared with surface vessels of equal size, the submarine can stay a very long time at sea. In addition, its seaworthiness is unlimited, and it is in this respect in a stronger position than surface vessels of equal size. Both these considerations are of special importance in regard to its use in naval operations.
8.) As a result of the element of surprise by which it is characterized, the submarine - apart from direct naval successes which it is sought to obtain by its use - exercises a great influence on the military and strategical position, because the enemy must everywhere reckon with its appearance, and is influenced in a correspondingly high degree in his strategical decisions and military operations (detours, defensive measures, safety patrols, zigzag course).
9.) It must be required of the submarine that it shall be able to travel both on the surface and under water. For this purpose it requires two different systems of propulsion, the diesel motor for surface propulsion, and the "E" engine: electric motor for underwater propulsion. The need for this dual propulsion system doubles the weight of the engines which the submarine is forced to carry, and entails a corresponding reduction of the performance of the individual propulsion unit. This is the cause of the relatively slow surface and underwater speeds of the submarine as compared with surface warships. This is the chief weakness of the submarine, which is of fundamental importance for its tactical use.
10.) Other weaknesses of the submarine are its restricted underwater radius of action, its low position in the water, and its great vulnerability.
11.) The weaknesses of the submarine must be offset by clever tactics, unscrupulous use, and obstinate persistence even when the chances of success appear slender.
12.) Fundamentally, the part of the submarine in naval tactics is to operate alone, in accordance with its character and its principal task of carrying out, unseen, its annihilating attack on an adversary of considerably superior fighting strength.
13.) Consequently, there is no such thing as a concentration of submarines for the purpose of cooperating, and supporting one another, in a collective naval action.
A concentration of submarines can only have the object of a common tactical employment, but always without any distinct, close formal-tactical connection.
From the time the concentration goes into action, however, each submarine carries on the fight, as before, separately and individually, although, in such circumstances, reciprocal indirect support, as, for example, by simultaneous attack, is possible.
14.) The principal task of the submarine, which is strong in attack and weak in defence, is the undetected, and therefore surprising, underwater or surface torpedo attack.
In no circumstances must the commander of the submarine allow his attention to be diverted, by lesser tasks, from this chief purpose, unless priority is expressly ordered to be given to other than offensive operations.
15.) During every attack, situations may develop in which a continuation the attack appears to the submarine commander to be hopeless, or impossible. Only if the submarine commander, imbued with the determination to win, and unrelenting toward himself, conquers these feelings, will it be possible for him - in view of the few opportunities of attack which the war at sea will provide - to achieve any success at all.
16.) In all operations against the enemy, the commander of the submarine is entirely independent, and free to make his own decisions, unless special cooperation is called for.
Do not see danger everywhere and in everything, do not overestimate the enemy, do not always seek to place yourself in his position, do not assume that everything that is going on in the theater of war applies to yourself-these internal reservations and scruples are a sign of uncertainty, and of a negative attitude, which impairs your ability to reach a decision, and endangers the success of the operations.
Audacity and a readiness to take responsibility, coupled with cool, clear thinking, are the pre-conditions and the basis of success.
17.) Free [Paragraphs marked "free" are those left open for future additions under the particular subject heading where they are found.]
18.) Free
B. How to Prevent the Submarine from Attracting Attention.
19.) The chief value of the submarine is its characteristic ability, which it possesses in an exceptional degree, to attack without being seen, and thus to achieve the element of surprise. The precondition of success is surprise. If the submarine is seen by the enemy, it is deprived of almost every chance of success. The commander of the submarine must therefore make every effort to preserve the paramount advantage of surprise, as far as it is at all possible.
20.) In order to remain undetected, before and during the attack, the submarine must be neither sighted, nor sound-located, nor detected by ASDIC.
I. Action to be Taken by the Submarine, in Order not to be Spotted.
21.) In every situation, both on passage (or approach) and in launching the attack, the submarine must be guided by the motto: "He who sees first, has won!" Untiring vigilance of the look-out involves success and safety of the submarine, and is, therefore, at one and the same time, a means attack and defence.
Consequently, when operating on the surface, a sharp lookout should always be kept, systematically organized in sectors (examination of the horizon for ships, of the surrounding surface of the sea for periscopes, and of the sky for aircraft). The most dangerous enemy of the submarine is the aircraft, by reason of its great speed. Consequently, during daylight and on moonlit nights, the sky should be watched with special care.
22.) To keep a conscientious lookout tiring; consequently, the look-out should be punctually and frequently relieved. Sunglasses should be held in readiness for all members of the watch.
Particular attention should be paid to the sun sector, in order to be safe sudden air attack.
23.) The periscope should not be used in daylight, on the surface, except special circumstances (for example, in remote sea areas; also as under No. 24). It is the raised periscope on the surface that makes the typical submarine silhouette. Similarly, on submerging in daylight, the periscope should not be raised until the submarine is well below the surface. In the same way, the submarine should not surface during the day, before the periscope has been lowered.
24.) If, for urgent reasons, such as overhauling, it should become imperatively necessary to raise the periscope by day when the submarine is on the surface, the additional height of the raised periscope can be used in suitable weather to send up a look-out with binoculars, provided that surprise attacks by hostile airplanes are not to be anticipated. If the weather clear and the sea calm, advantage can be taken of the raising of the periscope, for an all-round view. On account of the relatively week magnification of the periscope, however, and of the almost inevitable vibrations and movement of the vessel, this seldom serves a useful purpose. The danger of betraying oneself by the raised periscope is greater.
25.) In clear weather, do not allow yourself to be seen on the dip of the horizon. Submerge, at the latest, when the top of the funnel of the sighted ship is visible in the dip of the horizon. Some warships, besides having lookout posts with binoculars on the mast, have range finders of great optical efficiency in the foretop. In clear weather, therefore, one should never be able to see more of the enemy than the tops of his masts. Anyone who can see more - i.e., who approaches nearer - automatically runs the danger of being sighted, himself, by the enemy.
It is better to submerge too soon than too late, and thus lose one's chance altogether. The limits of what is possible in various kinds of weather can only be learned by experience.
The look-out on merchant ships, and the danger of being sighted at night, are easily overestimated.
26.) If there is a danger of surprise attacks in sea areas efficiently patrolled hostile planes and warships, and especially if the submarine is engaged operations there that require it to be stationary, it must remain underwater from dawn to dusk.
27.) It may also be advisable to remain submerged in misty or foggy weather. In poor visibility, the approach of ships can be more easily detected underwater [from the sound of the ships' engines] by means of the hydrophone, than on the surface by the look-out.
28.) This possibility of using the hydrophone to help in detecting surf ships should, however, be restricted to those cases in which the submarine is unavoidably compelled to stay below the surface. The hydrophone must not lead to inactivity [passivity] underwater, which would be wrong; it is an auxiliary instrument and no more, and can never be a substitute for ocular perception and surface viewing. As soon as visibility allows, the, place of the submarine is on the surface. Otherwise valuable opportunities of attack are lost.
29.) The danger of a surprise attack exists, in particular, when the submarine comes to the surface, especially after traveling long distances at considerable depth. When coming up from a considerable depth, an all-round sound location should therefore be carried out at a safe depth, where the submarine cannot be rammed; i.e., at a depth of approximately 20 m, at "sound-location speed." Next, the submarine should go rapidly through the danger zone at periscope depth, with the periscope raised; careful all-round look-out with and without magnification - submersion up to 9 m, depending on the weather, then lower the periscope altogether (see No. 23) and surface at high speed. The manhole of the conning tower is opened as quickly as possible, and the commander - with, at the most, one man who is especially good as a look-out - goes up. It is not until the surface of the sea has again been examined with binoculars, in every direction, that the compressed air cells can be completely emptied of water.
30.) By careful supervision, the submarine should be prevented from leaving traces of oil (leaking oil tanks, etc.). Patches of oil may also be left behind when submerging, as a result of a residue of air in the compressed air cells. Consequently, the submarine should not remain near the place where it has submerged.
31.) After the submarine has submerged, the periscope can be shown in a low position, and left there, up to a distance of approximately 4 to 5,000 m from the enemy, according to the state of the weather.
At lesser distances, the "sparing" use of the periscope begins, that is to say, the periscope is frequently and intermittently shown, each time for a little while, in a very low position where it is almost always awash, while the submarine travels at low speed.
For rules for the use of the periscope when attacking, see Section II, C, No. 125.
32.) For the color of the periscope, a dull, dirty grey such as is used for the body of the submarine itself should be chosen, as this color is the least easy to detect in all conditions of light. Green paint, or stripes or checkered patterns, are very conspicuous in a poor light.
33.) Every aircraft sighted should be regarded as hostile until the contrary is proved.
34.) Submarines on the surface are not easily detected from an aircraft when the sea is rough, unless seen in their characteristic outline against the dip of the horizon. If the sea is calm, the track (wake) of the submarine is usually seen first from the plane, especially if the submarine is moving at speed.
35.) The submarine must endeavor to keep a sufficiently sharp look-out to be able to see the aircraft before it is spotted by the latter. It is then master of the situation, and will soon learn to decide whether it must submerge, or can remain on the surface; if it is not certain that the latter can be done, it is better to reduce the chances of success by a premature temporary submersion, or a retreat to greater depths to avoid being spotted by the aircraft, than to spoil the chance altogether by being spotted.
36.) In good visibility, it is possible to sight the plane in time. It is consequently right to remain on the surface in areas threatened from the air, and to keep the area under observation. More can be seen above water an below. In addition, by remaining below, valuable opportunities of attack may be lost.
37.) Conditions are different, in particular, in areas threatened from the air, when the submarine is engaged in operations that cause it to remain stationary in misty weather, with poor visibility and low clouds. In such circumstances it is right to remain submerged during the day, because, if it has surfaced, the submarine may easily be surprised by aircraft suddenly appearing in near sight, without being able to submerge in time, and reach safety.
38.) The submerged submarine is most difficult to spot from the plane when all its horizontal surfaces are painted very dark. All other bright objects on the upper deck, as, for example, the insulators of the net wire, must have a coating of dark paint. In case of need, paint which has crumbled, or been washed off during the operations, must be replaced; for is purpose, a quantity of dark paint should always be available during operations.
39.) A submarine painted in this way can only be spotted by an airplane, if the submarine is submerged,
a) when the sun is shining, and the sunlight penetrates the water below the surface; without the sun, the water is a dark mass, which hides all objects from view;
b) when the surface of the sea is not so rough - approximately from motion [sea] 2 to 3 upwards - that the continuous refraction makes it impossible to see below the surface, even when the sun is shining;
c) when the airplane is almost vertically above the submarine. Because of the high speed of the airplane, it is very difficult to spot a submarine moving under water.
The conditions described above - sun, rough sea, position of the aircraft in relation to the submerged submarine - are relatively more favorable or unfavorable for the airplanes in sea areas with exceptionally clear, or exceptionally turbid, water, for example, in the Mediterranean, and in the Baltic at the mouths of rivers. In sea areas where the water is clear, so that it is correspondingly easier to look into it from airplanes directly above, the submarine must therefore submerge, in good time, to a greater depth, in order not to be spotted.
40.) Even when the submarine is not traveling at speed, if the sea is smooth, the tracks [wake] of the screw [propeller] of the vessel, and of the periscope, may betray the submarine to the airplane. When there is a danger of air attack in such conditions, the submarine should therefore submerge in good time, diving to a considerable depth, except when the sky is kept under observation through the periscope.
41.) What to do in case of air attack: see Nos. 266 to 270....C. What to do in Case of Enemy Air Activity.
266.) For general rules of action in case of enemy air activity see Nos. 33 to 41.
In areas specially threatened by enemy air activity; the lookout should always be taken by the best members of the crew, the A.A. weapons should be ready for action, and manned, and the serviceability of the weapons should be ensured by frequent replacement and trials (firing tests).
267.) On passage, the safety of the boat is the chief consideration during operations, the attack. On passage, the submarine should therefore dive as soon as it is known that the enemy planes are trying to locate it (by radar or visual search; when attacking, it should not allow itself to be diverted from its purpose to every reconnaissance operation of enemy planes.
268.) Enemy planes which have located the submarine by radar or visual search, attack, wherever possible, out of the sun, or on the course of the submarine or the direction of diving, and turn on their headlights at night shortly before attacking.
269.) Fundamental rules: When an aircraft not flying in the direction of the submarine is sighted in the distance, do not in general submerge, but turn away, show the narrow outline, and reduce speed, so that the line of foam in the wake of the submarine disappears.
If an aircraft sighted in the distance is flying toward the submarine, submerge at once.
If a plane is sighted at night only when its lights go on in flying over, or passing near the submarine, so that it must make another run in order to attack, the submarine should submerge immediately.
If an aircraft flying toward the submarine is sighted so late that the submarine cannot get down in time, do not submerge, but fight off the plane with A.A. weapons. After the first attack, submerge at once, before the plane can make another run.
270.) After submerging during an attack, always go down at Once to depth A, and double.
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