One of the great dives you can make on Grand Cayman is on the USS Kittiwake.
http://www.dive365cayman.com/kittiwake-cayman
With the top of the wreck just 15 feet below the water’s surface, and the bottom of the wreck at about 60 ft, both divers and snorkelers can safely enjoy the site. Prior to it’s sinking, large cut outs were made into most of the spaces on board, allowing divers good access to all levels of the ship. Divers can even swim into a hyperbaric chamber as the doors have been removed.
The USS Kittiwake was launched in July of 1945 as a submarine rescue vessel. The naval designation ASR stands for (Auxillary Submarine Rescue). The Kittiwake was the 13th vessel in the series.
On board the ship, you can still see some of the equipment that was used by the Navy to try to recover damaged submarines from the bottom of the ocean.
Any submarine can flood but early submarines were very dangerous to operate and many accidents occurred. Rescue ships like the Kittiwake saved numerous lives.
One key individual stands out as being a great contributor to the science of submarine safety and rescue. His name was Charles “Swede” Momsen and perhaps its a good idea to know something of what he accomplished. Some of his inventions are still in use today and remain onboard the wreck for you to explore.
Momsen graduated from the Naval Academy in 1919, just at the end of WW1. He attended submarine school and then served as the commander of several US submarines in the 1920’s. In 1925, while he was commanding the submarine S-1, another submarine, the S-51 sank after colliding with a surface ship. Momsen found the S-51 sitting on the bottom in just 130 ft of water. But because there was no technology available to quickly bring a downed sub to the surface and no way for the men to escape from the downed sub, he sat by helplessly as all but 3 men aboard the S-51 perished. The 3 that lived had been on the bridge and jumped overboard as the sub flooded and sank. The entire sub did not flood, just enough to give it negative buoyancy and send it to the bottom. Men were trapped behind water tight doors and perished from lack of oxygen.
This event inspired Momsen to think of a solution of how to get men off a sunken submarine. He set about designing a diving bell which could be lowered from a rescue ship. It would attach itself to a hatch on the submarine with a rubber seal so that the pressure in the bell and the pressure in the sub could be equalized. This would allow the submariners to transfer into the diving bell and ride up to the surface. At the time, the Navy rejected his idea as “impractical”. But Momsen would not be deterred.
After another submarine accident in 1927, with his diving bell idea on hold, Momsen came up with another idea. He envisioned a device that an escaping submariner could wear as they slowly swam to the surface from a downed sub. The device contained soda lime which chemically removes C02 from air and replaces it with 02. The user wears nose plugs and straps the bag to their chest. They breathe through a mouthpiece that connects to the bag with 2 hoses. They inhale air from the bag and exhale air with a high C02 level back into the bag. At that point, the soda lime chemically “scrubs” out the C02 and replaces it with 02. The soda lime is consumed in the process so it only works for a short period of time. But this is enough for a submariner to slowly ascend to the surface. It took a few years to get it right but in 1932 Momsen himself tested what he called the Submarine Escape Lung from a depth of 200 ft. One day the Navy brought some reporters in to see the device in action. One of them started calling it the Momsen Lung and the name stuck. Derivatives of the Momsen Lung are still onboard modern submarines. I was in Hamburg, Germany some years ago where a Russian submarine has been turned into a museum ship. Sure enough, even the Russians have their version of the Momsen Lung.
The Momsem Lung
While Momsen was perfecting the device, on his own time he returned to the concept of his diving bell rescue system. It took several versions but finally he and his co-worker, Al McCann, after scrounging parts at the Navy Yard, had a working system. Once they were able to show that it worked, the Navy placed diving bells on all the submarine rescue ships like the Kittiwake. You can see the Kittiwake’s diving bell welded to the deck of the ship with a big hole cut into the side.
In May of 1939, the submarine USS Squalus sank with 33 crew in 250 ft of water off New Hampshire. From an early sister ship of the Kittiwake, USS Falcon (ASR-2), Momsen and McCann made 4 trips down to the Squalus and rescued all 33 men. For the first time, submariners survived a sinking. Using huge air tanks, like those you can see today attached in racks near the top of the Kittiwake, the Squalus was eventually raised from the bottom and put back into service. For this, McCann and Momsen received a letter of commendation from then President Roosevelt.
Momsen’s greatest contribution was yet to come. With the start of WW2, Momsen was sent to Pearly Harbor where he took command of a squadron of submarines. After the attack on Pearl Harbor, the Navy’s submarines set about the Pacific filled with a blood lust to sink Japanese ships. Unfortunately they had all been provided with the new Mark 14 torpedo which had been designed and tested in the 1930’s when military budgets were cut to the bone. As subs started firing the Mark 14’s at Japanese targets they noted that an alarming number of shots appeared to just bounce off the target and never explode. Sadly , the Bureau of Ordinance blamed the submarine captains for lousy shooting. Unbelievably, this debate continued from December of 1941 until the middle of July, 1943.
Eventually a submarine returned from a war partrol to Pearl Harbor with 2 Mark-14’s left over from its original load. Of all the torpedoes fired during this sub’s war patrol, not a single one exploded. Taking the initiative, Momsen took these 2 torpedoes and some others and fired them at a sheer cliff on one of the Hawaiian Islands. It didn’t take long before he had a couple of duds. On is own, he swam down and tied a rope to the unexploded torpedo knowing that it might explode at the slightest touch. After hauling it to the surface and disassembling the contact detonator in the nose of the dud, he realized that there was a fundamental design flaw where the detonator pin was sheering before it could hit the detonator. Armed with irrefutable evidence, the Bureau of Ordinance was forced to agree and subsequently redesign the detonator pin. In September of 1943, some 20 months after the war started, the Navy was finally firing torpedoes that actually functioned properly. As you might expect, the effectiveness of the submarine force dramatically improved and by the end of the war, submarines would account for the majority of sinkings of Japanese ships. (about 1300 out of 2100 Japanese ships sunk)
Momsen made a number of other significant contributions but it was his work on the sister ships of the USS Kittiwake where his diving bell was put to such good use, that really made him famous.
You can read more about Momsen’s life in the book, “The Terrible Hours”.
Charles “Swede” Momsen