Similar to Were German WWII-era U-Boat crews allowed on deck? except for the USN. There's a whole lot of ocean between the mainland and Hawaii, and between Hawaii and the Imperial Japanese Navy, and later there just weren't many targets or IJN hunters around.

EDIT: to clarify, I'm asking about regular crewmen, during non-combat conditions, not the gun crew.

  • The US Navy lost 1 in 5 submariners over WWII - almost all of them in the Pacific or the seas to its west - en.wikipedia.org/wiki/… - the same reasons for the German's limiting numbers on deck during a cruise/patrol would apply to the US and other navies.
    – user13123
    Nov 16, 2017 at 3:19
  • @HorusKol, nevertheless there were considerable differences between the Pacific and the Atlantic-Mediterranean theaters. The Japanese had no radar (until some 1944, as I remember), they did not used a convoy system (until approx. 1944, and even since then the convoys were no match to British ones)
    – d.k
    Nov 16, 2017 at 20:03
  • @HorusKol, by the way, the figure 1 of 5 lost submarines does not seem large. For instance, the Japanese, while planning the initial stage of the war (to take Dutch East Indies, Burma etc.), expected to lose 1 in 3 of all their naval ships. It turned out to be much more favourable for them, but the point is, that in terms of WW2 20% losses were comparatively acceptable for many sides.
    – d.k
    Nov 16, 2017 at 20:16
  • 1
    @user907860 considering the US Navy as a whole only had a 1.5% casualty rate, the 20% in the submarine service is a lot. wikipedia
    – user13123
    Nov 16, 2017 at 21:18
  • @HorusKol, I regret, I cannot undo the comment upvote, since those figures in Wikipedia seem to be something of a different matter. They are about personnel, not ships, I'm sure, figures for ships would be higher. Because in the US there was no total mobilization, so many people were enlisted and discharged during the war (I heard once, that the pilots in the Pacific were supposed to complete a certain number of missions, after which they were removed from the front line). So men were enlisted and discharged, but ships continued to serve, you cannot compare losses in men and materiel.
    – d.k
    Nov 16, 2017 at 21:28

3 Answers 3


Long ago I read a book "Undersea Victory: The Influence of Submarine Operations on the War in the Pacific" by Wilfred J. Holmes, but it was in Russian translation and I'm unable to find its available English version now. So there may be some discrepancies because of re-translation.

The author himself was a pretty distinguished submarine officer of the US Navy, with enough authority to regard his opinion as significant.

In the book there are first two chapters, which were written in style of novel and cover the first missions of the USS Gudgeon and USS S-38 in December 1941-January 1942, and they give some impression about everyday life on board of a submarine during the war, while the submarine was on a combat mission.

I don't remember all the details in the book, but there are some quotations I was able to find in a minute, which pertain to the subject (note, this is a re-translation from Russian):

In the high seas a submarine must be ready for an emergency dive in case of any surprise. All the hatches on the deck, except the conning tower one, must be closed and tightly battened down until a moment, when the mission was over and the Gudgeon, while returning to her base, passed that entrance buoy in the fairway [the author is describing a moment, when the Gudgeon was leaving the Pearl Harbor naval base and is talking about a buoy which seems to be marking the entrance to the base or something like that — my note]. After the submarine was ready for a dive, she and everyone, who was on her board, became as if an autonomous particle, separated from the world.

I suppose this corroborates the opinion that there usually were no leisure sun-basking or fresh air breathing sessions on the deck.

And this was true even for subs, which patrolled Japan's coast and were based at Pearl Harbor, even during their voyage from Hawaii to Japan and back, because of many dangers: enemy surface ships, submarines, but especially aircraft, as Holmes describes:

During several days the submarine could move on the surface both at night and day, without exposure to significant danger and incessantly closing on a remote combat zone designated to her; but as she closed to the Japanese waters, surely it would be necessary to exercise more caution. The Gudgeon crossed the time demarcation line and entered the Eastern hemisphere.

As she entered waters in the 500-mile radius of the Japanese air base, she, in accordance with an order of the Commander of the Submarine forces [I'm not sure, if the title was back-translated correctly — my note], had to dive at dawn and move submerged until the full darkness, so that the enemy could not spot her. It was believed, that Marcus island, located at 1000-mile distance from Japan, was a Japanese naval air base. In order to reach the designated zone of patrol, the Gudgeon had to move 1500 miles through the waters, above which Japanese aircraft were patrolling.

Regarding life of board a submarine, there are several other excerpts, which touch many aspects, but no one mentions any crew members on the deck "to stretch their legs and get some fresh air", as was asked in the referenced question:

The routine of submerged move during day time exhausted the crew.

… The crew was divided to three shifts: one was being on duty, while the two others relaxed, made small repairs, tuned torpedo mechanisms, read or worked with documents.

… The radar, water-distiller and air-conditioning system — were three big advantages of the American submarines, but the Gudgeon was dispensing with the first two.

With the air-conditioning life was acceptable on board of the boat. On older submarines, without the conditioning system, heat and humidity, as the boat was submerged during all day, exhausted the crew, slacked them and caused skin diseases. As soon as the Gudgeon surfaced and her engines cooled, the air-conditioning system, which regulated temperature and humidity in the range most comfortable for a human body, started to work. On board there were chemicals to remove CO₂ from the air … Nevertheless, when the day ended, it had become pretty stuffy in the compartments and when the boat surfaced, fresh was meaning for men the same, as a drink of cool water for one suffering from thirst. Air pressure increased during the day, but it was possible to decrease it with an air-compressor. Still in certain cases the crew tried to avoid its use, since it created high noise.

I think, this answers the question to a certain extent. I cannot recall now an example pertaining to other periods of the war (the one provided describes only its initial stage), but I don't think that instructions regarding "strangers" on the deck could have changed significantly.

  • 1
    Excellent. One question: since the US wasn't in the war in "December-January 1941", is this a typo?
    – RonJohn
    Nov 16, 2017 at 20:05
  • @RonJohn, I added one more excerpt about air-conditioning etc.
    – d.k
    Nov 16, 2017 at 21:09
  • Absence of mention is NOT mention of absence. It is usual for the mundane to be omitted. Nov 16, 2017 at 22:58

According to "U.S. Pacific Submarines in World War II" by William P. Gruner,

Normal practice when on the surface was to have five men on the bridge at all times. The Officer-Of-The-Deck (OOD) had the conn, and was assisted by the Junior OOD. Two lookouts were normally stationed in the periscope shears to cover the forward sectors to the horizon, and one lookout was stationed aft on the bridge deck.

That was it. At all times, out of the harbor, they operated in war time conditions, which meant submersed most/all of the daylight hours, and at night, 5 men above decks.


A secondary weapon system on both German and American submarines in WWII were deck guns which required sailors to man them above deck. Typically 3 man gun crew, with more men running shells. deck gun

So not only were sailors in both navys permitted on deck, they would have been on deck significant time, given submarines only were designed to be submerged for limited times (attacks and evading). Mostly they were surface ships. The deck gun would have to be maintained every day to be in working order, just like surface ship guns. So sailors would be on deck even in peaceful waters to do this. Also u-boats threw their trash in the water and conducted navigation with sextants.. all of these things would occur on deck. Any time on the surface watches on the conning tower would be placed too.

Given that for the beginning of WWII the US navy didn’t even have a working torpedo (mark 14 torpedo) the deck guns importance would have been even more important as their most effective offensive threat. Submarine captains often considered the deck gun as their main weapon.2 [German commanders favored deck guns over torpedoes because they were more reliable.]2 The German torpedoes at least worked, which is more than we can say for US torpedoes early in the war, which the navy declined to test preWWII because of the expense. . Even later in the war when torpedoes would become more reliable deck guns would remain favored due to a submarines limited supply of torpedoes when on patrol.

The frugal, Depression-era, peacetime testing of both the torpedo and its exploder was woefully inadequate and had not uncovered many serious design problems. Torpedoes were so expensive that the Navy was unwilling to perform tests that would destroy a torpedo.

Toward the end of the war, as allied convoy tactics became more sophisticated U-boats deck guns became less effective, more dangerous and were eventually left unmanned.

  • I'm asking about regular crewmen, during non-combat conditions.
    – RonJohn
    Nov 16, 2017 at 9:07
  • 3
    @RonJohn: This answers the actual question, as phrased at its time of writing. If you meant to ask a different question, ask that. Nov 16, 2017 at 11:03
  • @PieterGeerkens the original, unedited question says, "There's a **whole lot of ocean between the mainland and Hawaii, and between Hawaii and the Imperial Japanese Navy, and later there just weren't many targets or IJN hunters around.*" To me, that refers to non-combat situations.
    – RonJohn
    Nov 16, 2017 at 15:01
  • 3
    @RonJohn if they had to be on deck in combat situations, then they would have to be on deck for drills, preparation, maintenance etc. A lot of the examples in this answer (disposing trash and navigation) as explicitly non-combat. The answer to your question is a resounding 'yes'
    – JeffUK
    Nov 16, 2017 at 16:19
  • 2
    Yes Submarines in WWII were basically surface ships 99% of the time. And as surface ships they had the similar on deck duties as any other surface ship in the Navy. Lookouts, maintenance, navigation, weather, etc.
    – user27618
    Nov 16, 2017 at 16:24

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