Each employee on a walking/working surface 6 feet (1.8 m) or more above a lower level where leading edges are under construction, but who is not engaged in the leading edge work, shall be protected from falling by a guardrail system, safety net system, or personal fall arrest system. If a guardrail system is chosen to provide the fall protection, and a controlled access zone has already been established for leading edge work, the control line may be used in lieu of a guardrail along the edge that parallels the leading edge.
The Chief of Naval Operations issued a directive on 7 December 1941 to "Execute unrestricted air and submarine warfare against Japan". The major mission assigned our submarines was the anti-ship (torpedo attack) mission. Early in the war Japanese capital ships were assigned as primary targets. Later, the priority was placed on merchant ships in order to cut off the Japanese supply of critical war materials, fuel, and food to her wide-spread ocean empire and to the home islands.On 13 April 1944, our submarines were instructed to give priority to fleet destroyers. The purpose was to reduce the major defensive strength of Japanese combatant groups and high priority merchant shipping.Later still, the highest priority was placed on tankers. The objective was to cut off fuel to the fleet and the Japanese home islands.U.S. World War II Submarine Operational Summary:Maximum number of U. S. Submarines in the Fleet = 288Number that made war patrols = 263Number of War Patrols made by Submarines in the Pacific = 1,474Number of days at sea by those Submarines = 70,838Number of Japanese ships attacked by submarines = 4,112Total number of Japanese ships sunk by submarines = 1,392Average number of merchant ships sunk/war patrol = 0.80Average number of naval vessels sunk/war patrol = 0.145Average number of all types of ships sunk/war patrol = 0.945Number of airmen rescued by Submarines = 504 by 86 SubmarinesNumber of Submarines lost on war patrol = 41, or 1 out of every 6.41 S/Ms = 15.59%Number lost due all causes = 52 out of the 288 in the Fleet, or 1 out of every 5.54 Submarines = 18.06%Number of U.S. Submarine Commanding Officers = 465Duration of the war = 1,347 daysU.S. World War II SubmarinesFleet Type SubmarinesThe large long range ocean going Fleet Type submarines comprised the major portion of the U.S. submarine fleet used against Japan throughout World War II. All Fleet Type submarines were similar in appearance, although the later ones were slightly larger than the earlier ones. Built in various classes, they had a length of 300 to 312 feet, beam of 23 to 27 feet, and draft of 14 to 15 feet. They were of double hull construction, with surface displacement of 1125 to 1500 tons, and submerged displacement of 1650 to 2400 tons. They were typically equipped with four main diesel engines, and one smaller auxiliary diesel. The latter was generally used for carrying the "hotel" load. They had a surface speed in a calm sea of 20 to 21 knots on four main engines at full power, and a cruising speed on two main engines of about 15 knots. They were equipped for submerged operations with two 126 cell electric storage batteries. A fully charged battery provided4 a maximum submerged endurance of about 36 hours at a creeping speed of about 2 1/2 knots, and a maximum speed of 8 to 9 knots for about 1/2 hour. Oxygen addition and carbon dioxide absorbent was needed after about 12 to 15 hours submerged.Fleet submarines were designed for a patrol endurance of 8 weeks (56 days). Endurance was limited by personnel, weapon, food and fuel consumption considerations. Most patrols were of 42 to 56 days duration. Three boats made patrols of 80 or more days; BLACKFISH (Sellars), THRESHER (Middleton), and GUITARRO (Dabney).The typical fleet boat had six 21" torpedo tubes in the forward torpedo room and four in the after torpedo room. They carried a maximum of 24 Mk. 14 or Mk. 23 steam, or Mk. 18 electric torpedoes, or mixed loads of steam and electric torpedoes, or mixed loads of torpedoes and mines. They were armed for surface offense and defense with a single 3", 4", or 5" gun mounted either forward or abaft the conning tower as desired by the Commanding Officer. In addition, they carried 50 caliber, 20 millimeter, and 40 millimeter rapid fire guns.Early fleet type submarines were designed for a test depth of 250 foot keel depth. This was gradually increased in later boats to 400 feet.Typical of fleet type submarine crew size in the early days of the war was 55 enlisted men. Of these, 42 were rated men, 7 were seamen, 4 firemen, and 2 mess attendants. Enlisted crew size grew to about 72. The number of officers increased from 5 to 8 or 9. Increases were generally due to added equipment such as radar and new sonar.In 1942 the U.S. Navy commissioned 32 new fleet type submarines. The numbers on patrol grew as newly built submarines were deployed until in November 1944 our submarines made 250 patrols, the most during any month of WW II.S-Class SubmarinesS-class submarines were the oldest and smallest submarines operationally employed by the U.S. during World War II. S-30 was launched on 1 April 1918 at the end of World War I, and was the oldest to make war patrols. The S-boats were built in various classes. They had a length of about 225 feet, beam of 20 feet, and draft of 15 feet. They were of single hull construction, with surface displacement of about 850 tons, and submerged displacement of 1100 tons. They had four or five 21" torpedo tubes in the bow, and could carry 12 Mk. 10 steam torpedoes. For surface action they carried a 4" gun. Their two main diesel engines gave them a maximum surface speed of about 14 knots in a flat sea. A 120 cell electric storage battery was provided for submerged operations. When fully charged, the battery provided a submerged endurance of about 36 hours at creeping speed of about 2 1/2 knots, and maximum speed of 10 knots for about 1/2 hour. They were designed for a test depth of 200 feet.5 At the start of the war the S-class submarines inflicted significant damage on Japanese combatant and merchant ships. Six S-boats of Submarine Division 10 were attached to the Asiatic Fleet and based at Manila. The base was lost inthe first month of the war, and these S-boats were sent south to be based on the east coast of Australia. S-boats based at Submarine Base, Coco Solo, Panama, were also sent to Australia. Still others were used for training officers and crews at the Submarine Base, New London, CT, and early in the war some S-boats were sent on patrol off the Aleutian Islands. By 1944, most of the active S-boats were based at the Naval Repair Base, San Diego, California. They were used as targets for training anti-submarine sonar operators from the West Coast Sound School at Point Loma, and pilots of Fleet Air Wing 5 based at North Island, Coronado, California.U.S. Submarine Command OrganizationsBefore the war all our submarines were attached to the three U.S. Fleets; Atlantic, Pacific and Asiatic Fleets. In the Pacific, 16 fleet type and 6 S-Class submarines were under the command of Commander Submarines Scouting Force, Pacific Fleet, based at Pearl Harbor. In the Far East 23 fleet type and 6 S-Class submarines were under the command of Commander Submarines, Asiatic Fleet, with staff in the submarine tender CANOPUS.Shortly after the Japanese attack, submarines of the Pacific Fleet at Pearl were placed directly under the command of Commander-in-Chief, Pacific Fleet (CinCPac) rather than under the command of the Scouting Force. The new organization was entitled Submarines, Pacific Fleet. Within a year the title was changed to Submarine Force, Pacific Fleet.In the Far East the Asiatic Fleet submarine command became Commander Submarines, Southwest Pacific (ComSubSoWesPac). Later, all naval units operating in the Southwest Pacific were designated the 7th Fleet, and the submarine command became Commander Submarines, Seventh Fleet.Each of the submarine administrative commands functioned as separate entities under its Fleet Commander. No official ties bound them all together. The geographical boundary between the operating areas assigned ComSubPac (or ComSubForPac) and ComSubSoWesPac was subject to slight revisions as time passed, but finally was stabilized at a line drawn along the 20° north parallel from the coast of China to a line just a few miles east of the Philippine Archipelago, then directly south to the equator, and then eastward along the equator. Temporary revisions were made to meet specific operational situations, but normally waters north and east of the line were patrolled by Pacific Fleet submarines, and waters south and west by submarines of SubSoWesPac.Individual submarines were organized into squadrons and divisions for administrative purposes. A squadron consisted of two divisions of 6 submarines each, and each squadron was assigned to a tender or base. Squadron and division6 commanders served wholly in an administrative capacity. The Force Commander controlled all combat operations and dealt directly with the Submarine Captains.Japanese Ship Losses To SubmarinesMerchant ShipsU.S. Submarines attacked 4,112 Japanese merchant ships* during 1,474 war patrols. Of these, the number of ships sunk was:
# There were 60 other fatalities in subs that were not lost. They include 26 lost in the BASS battery explosion, three in GROWLER (prior to her loss), two in MINGO and PARCHE, and one each in BILLFISH, BLUEBACK, BUGARA, CABRILLA, COBIA, COD, CREVALLE, GUDGEON, GUITARRO, HAKE, HALIBUT, LAGARTO, MUSKALLUNGE, POLLACK, PUFFER, S-31, SCORPION, SEADRAGON, SEAROBIN, SEGUNDO, SILVERSIDES, SKATE, SNAPPER, SUNFISH, TAUTOG, TULLIBEE, and TUNA. These made a total loss of 350 officers and 3,194 enlisted personnel for a total of 3,544.Torpedo ProblemsU.S. steam torpedoes Mk. 14 and Mk. 23 commonly fired in World War II had a number of faults. One was that the exhaust valves often leaked causing the after-body to flood if firing was delayed too long when the torpedo tube was flooded for firing. A corrective step in "routining" torpedoes was to seal the exhaust valves with wax. This was partially successful. A more serious problem was that too many of those which should have been hits were adjudged to be misses. At the start of the war they ran deeper than set causing them to run beneath the target. Tests showed that they ran 10 to 11 feet too deep. By August 1942 the depth problem was corrected by setting the torpedoes to run at shallower depths than originally designated for various types of ships. Also many torpedoes did not explode when seen to hit a target broadside. This major problem with the Mk. 14 and Mk. 23 torpedoes was identified on July 24, 1943 in the war's twentieth month by TINOSA's Commanding Officer, Lieutenant Commander L. R. (Dan) Daspit. He spotted the unescorted TONAN MARU No.3 west of Truk in broad daylight. She was Japan's largest tanker, rated at 19,262 tons. Daspit initially fired at long range on a large track angle and put two hits into her stopping her dead in the water. He then hit her with two more torpedoes causing her to settle slightly by the stern. Next he closed to less than a thousand yards and fired eight more fish at the tanker's broadside. Although he witnessed eight more hits, none of the warheads exploded. The problem was obviously in the exploder. Tests conducted by the Submarine Force at Pearl immediately thereafter finally pinpointed the problem with the exploder mechanism.12 Other problems were that a few made circular runs, on occasion hitting the firing submarine and some exploded prematurely on their way to the target. In addition, the Mk. 6 magnetic exploder was unreliable. On June 24, 1943, Admiral Nimitz sent a message to all submarines and destroyers directing them to deactivate the magnetic exploder and fire all torpedoes for impact hits.Production of steam torpedoes early in the war did not keep up with expenditures. The MK. 18 electric torpedo, copied from a German torpedo that ran up on the beach, was put into production as a step in correcting this problem. The Mk. 18 had a top speed of about 30 knots compared to 45 of the Mk. 14 (in high speed) and the MK. 23. Its speed was not consistent, and it had shipboard maintenance problems.Due to the steam torpedo shortage in late 1942 and in 1943 it became necessary to send some submarines on patrol with mixed torpedo loads, as well as mixed mine and torpedo loads. The higher speed Mk. 14s and Mk. 23s were generally preferred by Commanding Officers when there was a choice.Submarine Building YardsThe four primary fleet class building yards were Electric Boat Company at Groton, Connecticut; Portsmouth Naval Shipyard at Portsmouth New Hampshire; Mare Island Naval Shipyard on San Francisco Bay; and Manitowoc Shipbuilding Company on Lake Michigan. Submarines built at Manitowoc were barged down the Mississippi to the Gulf of Mexico. The Cramp Shipyard in Philadelphia also launched 12 fleet class submarines which were commissioned during the war. Two each of these were completed at Boston and Portsmouth Naval Shipyards.Fleet Type submarines commissioned during the war years were: 2b1af7f3a8