And does your submarine have a dorsal rudder, contra-rotating propellers, no bow/sailplanes, a combined rudder/stem planes, and slippery water outlets? Well, mine did. My submarine was USS ALBACORE (SS 569) and she was a test bed for these and other novel ideas. She had been constructed with a series of major modifications (phases) planned in advance to test different submarine concepts.
Built at the Portsmouth Naval Shipyard, ALBACORE was the yard’s pride and joy and was treated with loving care during her many modifications. ALBACORE was in the fourth and final planned phase of major modifications when I joined her as Ops in 1966. The following paragraphs briefly discuss some of the different features of this unique boat.
The installation of a high capacity silver-zinc battery as part of the Phase 3 modification package gave ALBACORE the capability (at the one-hour rate) to run faster than a Skipjack class SSN, thus making ALBACORE an ideal platform to examine potential high-speed ship control problems. The most apparent problem occurred when rudder movements would induce sudden and significant roll angles. Several different systems were tried on ALBACORE to counter the rudder-induced snap roll. One was mounting a dorsal rudder at the end of the sail. On turns, the dorsal rudder was moved opposite to the conventional rudder. While it was effective in countering the snap roll, the large dorsal rudder created a Jot of drag and greatly slowed the boat. A more effective system was that of limiting the amount of rudder motion. When running at speeds greater than 20 knots, a scaling system was activated that reduced the normal 30-degree maximum rudder angle to 5 degrees. A similar system was installed on later submarines.
Loss of depth control at high speeds could greatly reduce the time available to initiate recovery actions. To improve recovery chances, a series of ten large hydraulically operated doors (dive brakes) were arranged around the hull aft of the sail. Should depth control be lost at high speeds, the brakes would decelerate the boat by rapidly increasing hull drag. Opening like scoops into the water flow, the brakes were fully extended within seconds of activation by the combination of hydraulic system and water pressure. While the concept proved effective, the brakes weren’t considered feasible because the water flowing past the doors at high speeds tended to pop them open.
The four planned phases of modifications introduced some unique systems on ALBACORE. Her bow planes were removed and the conventional cruciform rudder/stem plane combination was replaced by four large control surfaces arranged in an x-configuration. The resulting steering and diving system used two airplane yoke-type controls in place of the old large hand wheels, a great improvement, and was the first integrated version of the airplane cockpit in a submarine. Rudder and stern plane commands were electronically resolved and the four control surfaces were individually positioned to produce the desired rudder/plane effects. The boat was very responsive, even at periscope depth.
As part of the Phase 4 modification, ALBACORE’s single propeller was replaced by two contra-rotating propellers for greater propulsion efficiency. Spacing between the propellers was initially set at 10 feet. After engineering trails, spacing was reduced to 7 .5 feet and later to 5 feet. (ALBACORE’s propulsion arrangement was unusual in that when running on the surface, the boat’s ahead dead slow speed was 7.5 knots!) Only USS JACK (SSN 605) was built with the x-stem and contra-rotating propellers.
The slippery miter project was being set up at the end of my tour in 1968. Special tanks, pumps, and piping were installed in the bow compartment for mixing and distributing a polymer solution out to ejection rings around the hull at the bow and sail. The solution served to promote increased laminar water flow over the hull, thereby reducing drag. Since only a limited amount of the polymer could be carried onboard, its use was viewed as a way to provide a short burst of speed. I left ALBACORE before the trials were run so I am unsure of the test results. I understand that, with this solution, ships’ speeds were reached at lower shaft rpm.
Duty on ALBACORE was highly prized. She was a good boat, had an excellent crew, and did a lot of interesting things with systems that most people never heard of, like the FAB. But that’s another story. To top it off, she was a heck of a feeder. Her major weakness was her high-speed Jimmy pancake engines which treated her dedicated enginemen badly.