USS Salmon - The sub that came within feet of crush depth

Added: 2026-05-05

[00:00:00]Heat up here.

[00:00:34]By late World War II, USS Salmon was not quite yet a decade old, but also was almost a second line vessel. She'd only been laid down in 1936 as the lead ship of her class, which along with the Sargo class that followed, usually compete for the spot of first true fleet submarines of the US Navy. She wasn't entirely without issue, being saddled by extremely unreliable engines that were fitted to half the class, and that created a lot of noise even when they did bother to actually work. She was also technically somewhat more lightly armed than later fleet submarines with four tubes forward and four aft instead of six and four as would be found on a ghetto. Still, despite this, she had been deployed to the Philippines and was in that area when Japan attacked Pearl Harbor on December 7th, 1941.

[00:01:29]She therefore had an active war almost from the start, attacking a couple of Japanese destroyers within a couple of weeks of the US entering World War II.

[00:01:37]Although her first three war patrols somewhat echoed Allied misfortune in the Western Pacific as the first started from the Philippines, the second started from the Dutch East Indies, and the third started from Australia as her unit and its depo ship were forced further and further south by the Japanese advance. Subject to the temperamental nature of early war Mark14 torpedoes as much as any other sub, she did nonetheless manage to open her scorecard with a rather notable kill. On the 3rd of May 1942, she managed to hit and sink the pre- dreadnaugh battleship Asahi, a veteran of the Battle of Tsushima, which was by this point a repair and depo vessel. Two torpedoes that actually worked for a change, and the PR dreadnaugh's almost complete lack of anti- torpedo defenses were enough to seal the surface ship's fate.

[00:02:29]By the end of 1942, Salmon had survived five war patrols and was recalled to Mayor Island, California for an extensive overhaul, which included new and more reliable engines, radar, and some 20 mm oricans. By mid-spring 1943, she was back in action, now based out of Pearl Harbor. And for about a year, she conducted yet more war patrols. By the time she returned from patrol number nine, she had been officially credited with four ships sunk and quite a few more damaged. Most of the latter courtesy of the ongoing issues with the Mark1 14.

[00:03:04]But by this stage, considerable numbers of newer and more capable fleet submarines were in service. The Sargo and Tambbor classes had succeeded the Salmons before the definitive World War II US Navy submarine class, the Gate, had begun to be mass-produced. A large number of the GTO successors, the Balaus, were now entering service. And even the successors to the Balaus, the Tenches, were actually well under construction.

[00:03:31]And so, while still useful, Sammon was temporarily diverted from regular frontline duty to undertake photo reconnaissance work, looking at a wide variety of Japanese-held islands, gathering considerable useful information for upcoming amphibious and air assaults.

[00:03:48]Upon her return, she was then sent back to May Island again for another overhaul. This one saw her receive a brand new conning tower made out of STS steel, new periscopes, some basic armor plating for the bridge, and new, stronger hatches, among other things.

[00:04:05]This greatly improved her capabilities.

[00:04:08]And so she headed back out to sea in early September 1944 in company with USS Silverides and partway to Pearl Harbor joined up with USS Trigger. The three subs began a series of joint training exercises at sea, as the US Navy now had enough submarines and had reduced the area of Japanese control over the Pacific sufficiently that they were now contemplating the use of small wolf packs instead of single submarine patrols, at least in areas where they thought there might be quite a few targets.

[00:04:40]There were a handful of mechanical issues on route, but these were soon fixed once Salmon arrived at Pearl Harbor.

[00:04:46]She then headed out on her 11th war patrol on the 24th of September 1944 accompanied by Silverides and Trigger forming as said a mini wolf pack. They reached Saipan and topped up on supplies from the submarine tender Fulton and on the evening of the 4th Salmon and Silverides headed out to sea. Trigger would head out separately and for the first couple of days sailing was good.

[00:05:11]But then heavy seas from the west hit them so hard that the two subs had to slow to a rate of advance of between 1 and three knots purely to conserve fuel while the crew enjoyed being tossed around by the waves.

[00:05:24]Eventually about a week after leaving Saipan they reached their operating area near the Ryuku Islands. But all they saw for several days were a wide variety of Japanese aircraft and the odd flight of US Navy types.

[00:05:40]Things did begin to change on the 16th, though. Some radar jamming was detected, and as the sun rose that morning, a patrol craft was spotted just 2,000 yards away. The patrol craft must either have spotted a periscope or detected a radar transmission as it soon turned away from the submarine and began accelerating.

[00:06:00]Salmon began to dive, and it was just as well because another patrol craft now popped up even closer, bearing down on the sub directly. It seemed that the first patrol craft was potentially acting as a decoy to draw their attention. Salmon dropped down to 150 ft below the surface as a blast rang out across the surface of the sea, but the crew never spotted what exactly that blast was. In any case, the patrol craft seemed to have given up after a while and salmon resurfaced and headed off to swap intel and movie reels with Trigger.

[00:06:33]One of the ship's officers now came down seriously ill and they were ordered to proceed southwest to rendevous with USS Barbble which was on its way home and to transfer the officer to the said sub before resuming their patrol.

[00:06:48]Toward the end of the month the battle of Lee Gulf was in full swing and Salmon Silverides and Trigger were ordered to deploy in a skirmish line to intercept potential retreating Japanese survivors.

[00:07:00]Trigger did briefly report spotting a pair of large ships, but that was about all the patrol line got for their efforts. The Japanese vessels still afloat after the debacle, evidently not crossing this particular picket line.

[00:07:15]And then on the 30th of October at about 0400 in the morning, Salmon's radar spotted a very valuable target, a now rare enemy oil tanker with four escorts making their way roughly east.

[00:07:30]The tanker, well aware of its status as a prized target, was zigzagging randomly, as well as changing its speed.

[00:07:37]Salmon attempted to get into a position from which to launch her torpedoes, but the tanker's random evasive actions were random enough to keep her safe from the submerged approach. And so Salmon took a risk and surfaced herself, using her radar to keep an eye on the target through various rain squalls. as this was an effort to get into a better firing position since the sub was more than twice as fast on the surface as she was underwater. While she did this, she also broadcast regular updates to her compatriots, and this brought results as Trigger came in from an unseen angle and managed to put a torpedo into the tanker, leaving it circling and slowing down. Salmon then got a front row seat as the four escorts saturated the area with depth charges. But Trigger had pulled off the submarine equivalent of a driveby and was merrily on its way out of danger. However, the pursuit had taken all day and it was now approaching evening. A full moon began to rise and it became immediately apparent that this might well highlight the submarine to the escorts. Salmon thus took a longrange shot with its four forward tubes using electric Mark18 torpedoes, but three out of the four decided to cosplay as dolphins, or perhaps more accurately, porpuses, and began leaping out of the water. Whether the moon or the leaping torpedoes betrayed Salmon remains unknown, but two of the three escort ships on the engaged side of the tanker soon turned towards the submarine at full speed. Salmon was in the middle of trying to come about to deliver a second salvo from the aft tubes if it was necessary, but as it was, a couple of the Mark 18s somehow still managed to find their way to the target. Although once the explosions cleared, the tanker remained stubbornly afloat.

[00:09:19]By this point though, Salmon had bigger things to worry about. And at 202, the order was given to go deep, stand at a head speed, and left full rudder. They were just passing through 310 ft of depth when a series of small explosions were heard, followed almost immediately by four much louder explosions as depth charges began to explode all around them. According to the official report, a total of about 30 depth charges were dropped, each of the four separate patterns consisting of from six to eight charges. The first and second patterns were received almost simultaneously, and one or more of these charges detonated very close aboard over the engine rooms, causing the collapse and flooding of the engine air induction piping and possibly some or all of the pressure hole deformation between the tank tops over the engine rooms. The final two patterns followed a short time later, but were not close enough to have serious effects. Although the boat was shaken up considerably, all of the 30 or so depth charges detonated aft in so far as could be determined on salmon. The commanding officer reported that severe flexural vibrations of the ship as a whole occurred during close detonations, stating that the conning tower vibrated up and down so violently I thought the ship was going to shake herself apart. I remember bending my knees to ease the shock. Damage to the ship was severe and widespread. Unattached gear and many inadequately secured small fixtures were hurled about during close detonations and presented an appreciable missile hazard to personnel in some areas. End quote from the official report. However, the worst effect was felt as the submarine suddenly began to drop like an elevator with the wires cut. Not only was there a loss of buoyancy due to the collapse and flooding of the external main engine air induction piping, but three of the deckside access trunks had been breached and numerous small leaks all along the ship's hull were reported, usually where fixtures and fittings pierced the hole. All of this added water and thus weight to the sub and made it severely negatively buoyant.

[00:11:28]Less obvious at the immediate time was fuel tank number seven, which had been ruptured, leaving thousands of gallons of fuel to float away and the mild buoyancy of the oil being replaced by yet more seawater. And to cap it all off, the pressure hole had been dented inwards in numerous areas, but this included particularly a section of the aft engine room adjacent to the manual controls for the aft dive planes. This dent knocked and locked the manual dive plane control into the hard dive position. The powered control shaft to the after dive plane was also broken by the explosions, leaving them seemingly permanently wedged in the hard dive position. All of this, plus, of course, the shock waves from all the depth charges being from above and around them rather than below, meant the sub was dropping rather rapidly stern first.

[00:12:19]Well, not only is this generally bad, but the test depth for the Salmon class was actually only 250 ft. They'd already been 60 ft below that when the depth charging started. And the crush depth, based on the US Navy standard of test depth being about 2/3 of crush depth, would be somewhere around 375 ft, meaning they'd only had about 65 ft of grace depth when they'd started to drop.

[00:12:45]And by the time anyone was able to look at a depth gauge, the stern was moving past that point with considerable enthusiasm.

[00:12:52]The crew were also left trying to solve all of these problems in the dark as power breakers had started to trip, some from short circuits and others from overload as power rerooed itself. Soon, not only were men having to play whack-a-ole with various circuit breakers, but when the main lights went out, it was found that a bunch of the emergency light systems bulbs had been broken by the depth charging, and so there was only patchy areas of the sub with any light whatsoever.

[00:13:20]The various air systems also began to spring leaks, and the hydraulic system locked up for good measure, leaving another party of sailors to try and shift the steering controls over to manual. Water continued to rise from leaks pretty much everywhere, but especially through the broken valves from the ruptured fuel tank. Broken glass and various other bits of debris were clogging the BGE pumps, and the fall only accelerated. Leaks in the conning tower meant that the command crew was also subject to a continuous shower of water while they tried to recover the situation.

[00:13:52]With all that said, the crew reacted quite fast with what they still had that was operational.

[00:13:58]Noticing that they were bow up. The motors were ordered to emergency speed ahead. The still functioning forward dive planes were set to 20° up angle and the auxiliary tanks were blown. This stabilized the situation somewhat, leaving the sub with its bow pointing up at a rather jaunty angle as the depth gauge reported that the stern was somewhere around 400 ft below the surface.

[00:14:22]Gradually, salmon began to rise. She was still negatively buoyant, but with the force of the propulsion system straining, it was just enough of a counter. The depth gauges showed the sub clawing back up until they got to around 300 ft in depth. But when the bow planes were ordered down to level the boat out and speed was reduced to standard ahead, the problem of still being increasingly negatively buoyant became rather immediately apparent as without the considerable upward thrust from the propulsion system, the sub began to sink rapidly once more. The safety tank was now ordered to be blown, the bow planes ordered back up, and emergency speed rung back up again. But having leveled the sub and taken on more water through the various leaks, all this meant was that they were now falling somewhat forward as well as down. The sub plunged still deeper, reaching a somewhat worrying 500 ft, over 100 ft deeper than the sub should theoretically have been when it should theoretically have imploded before the heavier weight of the flooding stern managed to result in the bow being high enough uh once more for the motors to provide upward as well as forward force and the sub began to rise slowly once again. Conscious that they were still less than 10 minutes since the first depth charging had occurred and the escorts would surely still be in the area. The salmon was coaxed up to 150 ft before another attempt to level off was made. However, this had similar predictable results to the last effort, only somewhat worse as continued water ingress meant the sub was even heavier now and soon they're on their way back down again, except now even faster. The same counter measures were tried, but this time before they stabilized their plunge, the control room depth gauge read 578 ft, 200 or so feet below theoretical crush depth, and the hole was groaning with the effort of not turning from a roughly cylindrical shape into a rather flattened rectangle. And that was the control room depth gauge. Who knew how deep the stern was?

[00:16:27]As the sub hovered in the void of the ocean, it was realized that they really only had a few minutes left unless they took some rather radical action. The batteries were now almost entirely depleted from the constant emergency speed power draw. The sub was getting heavier by the second and water was reaching the level of the motor casings anyway. And then somebody helpfully pointed out that even with the last of their battery power straining, the depth gauge was still showing a gradual increase in depth.

[00:16:56]It was clear that trying to stay below the surface simply wasn't viable. Salmon would not survive another plunge, and so they were decided it was better to take their chances with a gun battle on the surface.

[00:17:09]Thus, all remaining tanks were ordered to be blown, and the crew stood by for a surface action as the sub rose once more from the depths.

[00:17:17]It turned out at this point that the stern dive planes being stuck in full dive position was actually helping, weird as it sounds. This is because on a sub with four and a half dive planes, if you want to dive quickly, you want the sub to be angled downwards so that your propellers can help. The exact inverse of what Salmon had been using to try and stay up. Thus, the aft dive planes were pointing up as this would make the stern rise relative to the bow so that the bow could dive. Of course, if you were actually trying to dive, the bow planes would also be pushing the bow down.

[00:17:53]What this meant for Salmon at the moment was that as Stammon's stern had grown so heavy that it was dragging the rest of the sub down with it, as long as she had forward momentum, the after dive planes were in fact constantly trying to make the stern rise, giving just a little bit of lift, which might just have kept it high enough to avoid those last few feet that would surely have led to an implosion.

[00:18:20]With that said, the aft end of the pressure hole was distorted enough that you could be forgiven for thinking that salmon had run into a Kraken armed with many, many large hammers. As the pressure had come so close to breaching the hole that permanent indentations either side of pretty much every frame had occurred, resulting in a rather wavy shape to a pressure hole that should have been nicely cylindrical.

[00:18:44]At 2030 hours, just 17 minutes after the first plunge, salmon popped to the surface. Not like a cork, but more like a recalcitrant teenager being dragged out of bed. To say that she was afloat was stretching the term somewhat. The sub was listing drunkenly at about 15° to starboard. The decks were pretty much a wash instead of being well clear of the water, and there was precisely one small charge remaining in one bank of air flasks. All the rest had been expended or leaked. Oh, and the air compressors had all flooded and shorted out, so refilling those air flasks wasn't happening anytime soon. There was also a low pressure air system to complement the shorted out highpress air system. And while it couldn't refill all the air flasks quickly, it could at least in theory be used to write the list. That is if the low pressure pump wasn't also full of water and the electrical system that controlled it hadn't shorted out. As the crew contemplated possibly having to fight it out on a lurching barely a float and listing submarine, they also realized that until they actually got out there and looked around, they also had no idea if the hatches would even open or if they'd been bent and distorted inwards, if the diesels would fire up at all, or if the deck guns were even still there, let alone in working order.

[00:20:05]Luckily for Salmon, she'd surfaced about 7,000 yd away from the nearest Japanese escort ship on the far side from the moon and thus in the area of most darkness. The large oil slick from the initial rupture of fuel tank 7 was attracting the escort's attention, and they were still dropping depth charges on the area, which was fortunately now some distance away from the sub's troop position.

[00:20:28]This bought precious time for damage control efforts to kick in. Soon, one of the main engines was engaged, and 20 minutes later, another one was brought up to speed after various exhaust valves were persuaded to open by force. Another 10 minutes, and the low pressure air system was drained of water, dried out, and initiated. This managed to clear the list and added a little bit more overall buoyancy to the sub. A few of the compressed air tanks, those that didn't immediately leak like saves, started the process of repressurization, or at least as best as the low pressure system could do. At this point, one of the escort ships seems to have noticed salmon, or at least noticed something off in the dark and opened fire at about 5,000 yds range with its deck guns, but otherwise made no particular effort to close.

[00:21:15]Salmon elected not to draw further attention to herself, and at 21:15, another 15 minutes later, a third diesel was coaxed into life. Unfortunately, when they tried to get the fourth engine running, which was actually number one engine, it turned out that this engine was completely flooded and one of its drive shafts snapped as a result.

[00:21:34]Although this left them with a top speed of 16 knots instead of their normal 21, it was good enough. Judicious use of hammers reset the stuck after dive planes, and the power steering was also restored, as were the billagege pumps after somebody found some thick gloves and cleared the debris that was clogging their intakes.

[00:21:53]All of the radio antenna had been destroyed and so an emergency antenna was brought up and wired in. And at 21:30, she was able to radio her condition and location while also dodging fire from one of the escort ships who had resumed taking long-range pot shots as salmon was making large circles to try and keep the range open.

[00:22:12]Half a dozen nearby US subs began sending open voice radio messages to the salmon in an apparent effort to demoralize the Japanese. While the Japanese ships didn't flee, the other three escort ships certainly kept patrolling and pinging away as if they were looking for other submarines that might be closing in on them, which left just the one to keep harassing Salmon.

[00:22:34]By midnight, the other three escorts had formed a skirmish line, but not really moved to assist their fourth ship, and Salmon had occasionally been trading fire with the more aggressive escort.

[00:22:45]But with everything, including the gun sights on the guns, broken, they were left lobbing shells into the darkness and hoping for the best. with the loader looking for shell splashes and manually calling the results to the gun trainers.

[00:22:59]However, the first escort decided it was fed up of this chase and decided to try and close in directly for better gun accuracy. As the range closed to 2,000 yd, Salmon then turned towards the escort and countercharged, opening up with all her available weaponry, including the anti-aircraft guns. This seems to have had a marked effect as the escort ship, after having been badly shot up, drew away without attempting to re-engage or even continue firing.

[00:23:27]Salmon headed for a rain squall for cover as the other three escorts bore down at last to try and avenge their compatriate. A scattering of fire from Salmon's guns managed to persuade them to stay at range just long enough that she was able to get get into the cover of the rain squall.

[00:23:43]Once clear of the immediate area, Salmon set course for Saipan and radioed for further assistance. The following night, her packmates Trigger and Silverides appeared along with USS Sterlet, which had taken the opportunity to finish off the tanker on its way. The trio of intact subs escorted Salmon all the way back to Saipan, where she was patched up as best they could, and then she was sent on to Pearl Harbor. Pearl took one look at the mangled sub and declared she was going to Hunter Point, San Francisco. They surveyed her damage and declared, "Well, actually, no, she's going to the Navyyard in Portsmouth, New Hampshire, patching her up just enough to survive the trip through the Caribbean and the Atlantic." It was decided that she was far too badly battered to be made fit for frontline duty again, and so she would instead be made into a training and experimental submarine. She eventually arrived in New Hampshire in late February 1945.

[00:24:36]But after over half a year of work there, there was still a lot to do. And with the war now over and many fully operational submarines being made available for training and testing work without needing extensive refits, it was decided that further work to Salmon just wasn't worth it. She'd managed to bring her crew home, but there was no further use for her in the Navy, and so she was decommissioned in April 1946, just 11 days before the 10th anniversary of her keel laying. And then she was sent off for scrapping.

[00:25:07]Salmon ended her career officially credited with sinking seven ships for a total of 31,800 tons and damaging 11 more for a total of 56,400 tons, as well as receiving a presidential unit citation for the action and of course bringing her crew safely home through one seriously nerve-wracking roller coaster. That's it for this video.

[00:25:30]Thanks for watching. If you have a comment or suggestion for a ship to review, let us know in the comments below.