Quadruple your speed in a decade
(first posted 1/8/2012) In the very early twentieth century a submarine was a surface craft that could be submerged. If it had to transit oceans to join a fray it was done on the deck of another ship (therefore, they called them boats). Sixty years later they were able to transit oceans submerged at speeds approaching President Nixon’s speed limit (excess of 40 knots). The speed was mostly developed between 1945 and 1953.
What sort of innovations were needed to make this change? That’s easy you say. Nuclear Power. Nope. Nuclear power allowed them to stay out longer but I am talking about the diesel electric submarines that we discussed in an earlier article.
Hint: It’s the same thinking that took us from the Stanley Steamer breaking through the 100mph mark to the current land speed record. It didn’t hurt that we stole a bunch from the Germans.
The Gato was the first fleet boat. It is the sub class that did the most to win WW2. It was called a fleet boat because it was designed to operate with and keep up with the fleet. It was to be a scout for battleships. The job was to find the enemy, report on the speed and composition of enemy forces, and whittle away at the opposition. Then they were to operate in support of the battleships during the massive gun battles that were to follow. This strategy was developed over the two decades following WW1. Something happened on 07 Dec 1941 that rendered this strategy obsolete.
On 08 December we were essentially left with no battleships to support. Lucky us, however, the same traits that allowed subs to support battleship groups were the traits that allowed us to roam alone or in groups and destroy japanese shipping.
There were two failures of the Japanese attack.
The first was timing. The attack was launched while the three pacific carriers were at sea. This was known by the attackers but thought not important. The result was the development of strategy that favored the carrier over the slower battleship.
The second was ignoring the submarine base. That base was important to all salvage operations immediately following the attack. It was about all we had that wasn’t severely damaged. Also that base was the nerve center that launched pacific submarines throughout the war. That gets us back to this boat. It was the primary boat used during WW2.
This boat could carry the fuel and provisions for roughly 75 day patrols. She could go from surface to fully submerged in 45-50 seconds. The superstructure was free flooding and caused the boat to hang momentarily before submerging. When full of water it would submerge. To shorten that time large limber holes were cut into the superstructure and by the middle of the war the time was reduced to 30-35 seconds. That was truly important because they were not heavily armed for the surface even then. To fully appreciate how fast that was you would have had to be there.
If you think there is little difference between these two boats you are wrong. However, you would be excused because they certainly look the same. Don’t change a winner. The biggest difference between them is the thickness and composition of the pressure hull which added about 100 feet to the operating depth of the boat. The Tench class had very little change as well. Most of the boats of the tench class were cancelled because the war was winding down. The engineering plant had little change between the three classes. So what after all, does that leave us with.
We have a surface ship that can submerge. For simplicity I chose to use the Balao statistics. It is capable of going perhaps 20 knots on the surface. Submerged it could make 8-9 knots. Probably 90% of it’s travels were done on the surface. Even attacks made at night were on the surface. At two knots submerged it could go for 48 hours but without fresh air the crew could make it less than 20. It could travel for 11,000 nautical miles on the surface if you kept the speed to 10 knots. That was the fleet boat. What happened to change it to the submerged high capacity weapons system it is today.
This German type XXI boat was constructed from 1943 to the end of the war. The changes were many but the thing I consider most important is that it was the first boat capable of making more power underwater than on the surface. Obtaining possession allowed us to skip through several evolutions allowing us to reach speeds with diesel electric subs that apparently, are still classified.
If you were expert at aerodynamics (and what gearhead isn’t) you would probably have already noted that the bow of the Gato and Balao are designed like that of a surface craft. That would tend to force the bow up while slowing the boat down. I am sure that none of us think the deck guns or masts resembling an antenna farm add to the submerged speed. Sonar that we took from the Germans allowed us to better operate submerged. The GUPPY conversions were so that the physical plant could better operate in these same depths. GUPPY means Greater Underwater Power Propulsion with the Y to be cute.
Fleet Snorkel boats. Because we were not yet so adept at spending money we didn’t have, there was a shortfall of funding to modernize the whole fleet under the Guppy program. For those boats that were left out the new sail was installed, covering among other things, a snorkel. As you can see the bow is unchanged from the basic fleet design.
All of these modifications from Guppy 2 to Guppy 3 included snorkel pipework. This system allowed inlet air to be dumped into the submarine atmosphere and exhausted directly from the engine to a diffuser plate a few inches under the surface of the water. Atop the inlet was a snorkel head valve that operated much like the epiglottis at the top of your trachea. It allowed you to move under diesel power, charge batteries and give the crew much needed fresh air. In my opinion it was exceeded in importance in the development of a true submarine only by the nuclear reactor.
The Guppy conversions were in several stages but anyone who claims to be an expert will find himself tripped up. The Guppy 1 would have looked much like this. The bow would be cleaned up. The batteries would have been doubled. One of the four engines was removed in most of the Guppy 2 boats. That obviously reduced power production. The masts would be hidden under this aerodynamic (hydrodynamic really) sail. The Guppy one reportedly did not have a snorkel. All others did. The reduction gears would have been removed and the electric motors attached directly to the shafts to reduce noise. The Bang as pictured here is not a Guppy 1 and probably is a guppy 2.
Guppy III:Because of the increased battery capacity there was no room left for the crew and equipment. Although not all boats were identical a 15 foot section was added to the hull of the Guppy III. This allowed the boat to retain all four engines and still have a crew. The sail was not a step sail. It was very tall and designed to keep lookouts above the waves. It also provided a lot of adventure when my first capatin ordered a battle surface. The sail was full of water and keeled over until that water drained. That caused a great deal of unanticipated and unappreciated excitement.
The three humps on the deck were a passive ranging device that worked on triangulation much like your visual depth perception. If you had these sonar devices you were assured of spending time at sea. I was a sonar watch stander on my boat and qualified on this gear. I spent a lot of time at sea.
Tang class: This is the boat that was designed to incorporate all the Guppy features when built.The engines were a departure from the past two decades. Instead of a v design or opposing pistons, these were General Motors diesels that were of a pancake design with vertical cranks. The cylinders were radial and the generators were under the engines. The idea was to place four engines in one engine room. The engines leaked. The generators shorted out. The system was a failure.
The design was changed to conventional engines and the boats immediately developed reliability. This class was the last diesel electric design to resemble the WW2 boat.
Admiral Rickover got all the ink. He was insufferable but he deserved a batch of credit. There were people working on a parallel design that deserves more credit for the speed of today’s boats. Rickover’s legacy should be for the endurance of the boat. The David Taylor Model Basin in Carderock, Maryland deserves the credit for how fast they go. For those of you who can appreciate the “used bar of soap” design of the Taurus this will be easy to understand.
I don’t know how fast the Albacore would go. They completed it in 1953. We were told it was in excess of 25 knots. I do know that it was faster than the first nuclear boat, the USS Nautilus. I really don’t want to know how fast it was. As an experiment I don’t think it ever stopped during it’s lifetime. As an operational unit it never existed except for a competition target, however, there were some in the fleet that were very similar.
This class contained three submarines. It had the last operational diesel in the fleet. They could snorkel very fast. If they needed to dive they could go very fast….. for about half an hour. They were used as a template for the fast attack nuclear submarine that saw through to the end of the cold war.
This is the first nuclear powered sub. If you think it looks much like the postwar Guppy and somewhat like the WW2 Fleet boat we would all agree. However, it was capable of going fast (not as fast I am told as the Albacore or it’s descendants) for much more than a half hour. This boat and the first generation nucs that followed were capable of going under the ice pack and staying there for a while. They generated their own oxygen and scrubbed the CO2 continuously.
Now you may be thinking: Why didn’t those guys just put the stuff from the Nautilus inside the hull of the Albacore. Good idea. Then you are probably wondering – Why not name it after a fish and make a batch of them. Excellent choice.. This picture is of the Scorpion because of personal association. Virtually all submarines manufactured from that time were similar.
BTW… if you noticed the guppy2 in the background, pat yourself on the back. Some of my friends asked me about some of these things after the first article. I don’t think some of them knew I had even been on the boats. I am generally reluctant to write about the boats but finding most of this information online has convinced me I won’t get locked away. I know there is more to say and you can feel free to say it. I hope you enjoyed the story and found it worth the read. I haven’t said this much about the boats since 1969. I am about tapped out.