Two separate and distinct methods of navigation were employed in the Nautilus on her transpolar voyage from the Pacific to Atlantic Oceans in mid-summer 1958. After we emerged from under the ice, obtained a celestial fix, and could again depend on our normal navigational procedures, we knew that either method or system by itself would have been sufficient to ensure a successful passage from the Chukchi Sea, north of Bering Strait, to the Greenland Sea.
The close agreement at all times between positions obtained from each system during the transit gave us a great deal of confidence, ensured that failure to one type of equipment would not in itself endanger the success of the transit and, probably what is most important now, made the hydrographic data obtained much more reliable than would a one system track. At the time, however, as need not be pointed out to those who go to sea, the most important result of this coincidence of position data was the number of gray hairs that it saved our skipper and perhaps all of us on board. Throughout this article I would like the reader to bear in mind that praise of the performance of one type of equipment is not meant to take credit away from another system.
Dead Reckoning
More than anything else, the navigation department aboard a nuclear submarine must be able to dead reckon. Conventional navigation procedures aboard the Nautilus in transit involved dead reckoning with a fix being obtained once a day at the most and occasionally once every three or four days. This practice is made possible by the fact that we transit in the open sea and with highly accurate gyrocompass and underwater log equipment. On one transit from Panama to San Diego, we traveled about 3,000 miles in 65 days without a fix. When the transpolar passage was proposed in January, 1958, we had only our conventional navigational equipment on board. With our knowledge of its capabilities coupled with our experience in northern latitudes last summer, we determined that we could make the trip with installed equipment. More than any other single instrument, the Sperry MK 19 gyrocompass gave us this surety. We had seen it operate at 86°N and 87°N before, and we had observed its reliability and accuracy for a half a year. As long as we had the MK 19 we could make the trip.
With the above in mind, we held a conference with representatives of the Sperry Marine Division. Hypothetical problems were presented to them. With their answers, plus our previous experience in the Arctic, we drew up a sequence of events for compass operation while crossing the Pole. This deliberate casting of events was designed to make use of the high latitude capabilities of the MK 19. The MK 19 was used in its north-seeking mode during the approach to and the crossing of the Pole. Some seventeen miles after crossing the Pole it was turned off, slewed 180°, and restarted. At latitude 86°N it had settled on the meridian and was again used for steering. Operated in this manner, the north-seeking force, even though small, was used to its maximum to ensure that the Pole was attained. As the horizontal component of “earth-rate” approached zero, the compass would gradually lose its north-seeking capability but would remain an excellent directional gyro. The compass stayed on the true meridian at least to 88°N and possibly 89°N. From this time until we secured it after crossing the Pole, its drift rate as a directional gyro (DG) was negligible and ensured that a straight course was steered.
Two directional gyros were used to monitor performance of the MK 19 and to ensure that a great circle was steered during the approach to the Pole, the crossing, and the trip southward. Drift rates of the Sperry MK 23 and the Sperry Gyrosyn in the DG mode had been checked repeatedly over long periods since April. Both had shown that they would produce the required performance. They had extremely small drift rates. During the northward approach the drift rates of these gyros were checked against each other and against the MK 19 while still in moderate (74°–86°N) latitudes. After crossing the Pole, steering was switched to the MK 23(DG) until the MK 19 had returned to its settled position. Its expected drift rate was then confirmed. From this data we computed our position, switched back to the MK 19, and set course for the Greenwich Meridian.
Along with accurate course information, accurate speed indication was necessary if the dead reckoned position was to be reliable. Prior to departure from New London the log, an electro-magnetic type manufactured by the Control Instrument Corporation, was calibrated as best as it could be on a measured mile. Shallow water in the vicinity of the measured mile precluded calibration under the exact conditions we expected. With this rough calibration checked underway in the anticipated speed range over a period of almost three months, we had a very accurate picture of the log’s errors. These known errors were applied to give accurate distance traveled for dead reckoning. Thus using course information from a north-seeking gyrocompass to within about a hundred miles of the Pole, followed by accurate directional gyrocompass (both MK 19 and MK 23) information for about the next 300 miles coupled with distance by underwater log, a careful and exacting DR was kept throughout the transit. As anticipated, this one system provided sufficient accuracy in itself to make the navigational aspects of our trip a success.
Inertial Navigation System
In April, 1958, an inertial navigation system was installed in the Nautilus. Ostensibly it would be used for the scheduled trip to the Arcticfrom the Greenland Sea in August, 1958. This system, designated as N6A, was manufactured by the Autonetics Division of North American Aviation Corporation. Since it had not been designed for shipboard use (the Navy borrowed it from the Air Force) nor had such a system been operated under practical conditions aboard a submarine, initial plans for navigating the Arctic were made on the assumption that only the conventional methods would be available. Data gained from the N6A would be over and above the minimum required for such a transit. The N6A required a comprehensive de-bugging during the first several months of its operation. At times many of us doubted if it would prove of any value on our trip. In fact, however, largely through the personal efforts of Mr. Thomas Curtis, the Autonetics engineer in the Nautilus, the system operated continuously and successfully throughout the submerged polar transit. It provided accurate position and heading data particularly during the approach to the Pole, its crossing, and down to the Greenland Sea. The fact that conventional methods yielded generally the same data should not detract in the least from either the performance or the importance of the inertial navigation system.
Throughout the transit, data were taken hourly from the auto-navigator. Its inertial and dead reckoned positions were put on the plotting sheet in use. In addition, ship’s head from the N6A was logged and compared to head by steering compass. In the immediate vicinity of the Pole, data on position, actual meridian being followed, and heading were taken more often. Of particular importance was confirmation of longitude on either side of the Pole and confirmation of ship’s head. These computations yielded the important check on directional gyro performance when such a check was highly desirable and provided an additional heading reference with which to observe the settling of the MK 19 north-seeking compass after crossing the Pole.
In addition to outputs for conventional latitude and longitude, the system provided transverse co-ordinates equivalent to latitude and longitude, except with the co-ordinate pole on the earth’s equator, and direction cosines on the axes of the stable platform. The plot of direction cosine outputs proved particularly valuable in the final approaches to the Pole, since the information in the computation of directions cosines is most accurate near the Pole. These cosines represent the accurate dynamic determination by the system of the angular relationships between the spin axis of the earth and the three axes of the platform. The fact that an inertial system not designed for shipboard operation was able to provide accurate navigational information continually during this transpolar passage was truly an amazing feat. Without a doubt shipboard inertial navigation is a reality. It will overcome many of the navigational problems we now face particularly in attack type submarines. Its contribution to high altitude navigation is of course revolutionary.
Magnetic Compass
Since the Gyrosyn compass was used primarily as a directional gyrocompass, the ship’s Magnesyn was the only magnetic meridian reference used. The binnacle for the compass is located topside and reads remotely below decks. One of the major shortcomings of the equipment is the inability to adjust (compensate) it submerged; therefore, it was adjusted for moderate latitudes and was last swung for residuals at 71°N. The compass did operate as well as was expected. Even though at times the deviation was high, its readings were constantly monitored, especially after crossing the Pole, for a change in deviation indicating a course error. No such error was found, but it remains a fact that a good magnetic compass even though readings are approximate and/or relative is still essential to navigation in Polar regions as a basic backup should all other equipment fail simultaneously.
Power Supply Reliability
Certainly no gyrocompass or inertial navigation system is any better than the reliability of its power supply. It was realized from the beginning that if navigation of the Arctic and the Geographical North Pole was to be successful that we must first ensure adequate and continuous electrical supply to all equipment. Their power supply must be in other words a “vital-vital” circuit. Such reliability was attained but not by accident. Motor generators were added to the ship. Circuit breakers were checked even to the point of returning them to their manufacturer and, in fact, changing some of their original design requirements, and all circuitry was closely examined to find flaws. The reliability gained from the above effort was well worthwhile and insured that simultaneous failure of all major navigational equipment would not occur. The advanced planning of the Electrical Division of the Nautilus and of the many people outside the Nautilus who helped in this ensured that the transit would be a navigational success.
Narrative
Prior to our departure from either New London or Pearl Harbor and/or during the first phases of our trip, that is to say our transit to the ice cap, preparations and plans had already been made to determine the reliability, accuracy, and expected output of each piece of navigational equipment. Our modes of operation had been determined, and casualty procedures reviewed. The entire trip had been made many times on paper, in conferences, in our minds, and even in informal discussions. Most operations during the transit itself would be automatic.
At 0432 on August 1, 1958, we obtained our last fix on the Pacific side. We were lucky and in addition to radar on a reference at Pt. Franklin, Alaska, we were able to get one strong loran line and a marine sextant altitude on the moon. We dove and proceeded towards the North Pole knowing that our next fix would be in the Greenland Sea. We kept our track, as is custom in the Nautilus, both on a chart and on a plotting sheet. Plotted on these were our dead-reckoned position, the inertial position, a DR type solution from the auto-navigator, and an estimated position. At least each hour all compasses and heading from the N6A were compared. The results were recorded. This general procedure was followed during the entire approach to the Pole.
Our master compass, the MK 19, was in its regular north-seeking mode and being monitored by two other gyros in the directional mode. We expected that somewhere north of 87°N, the MK 19 would become directional instead of north-seeking, but it would still enable us to steer a straight course over the Pole and down the other side. By the time we were less than 100 miles from 90°N the master compass was still within navigational accuracy and showed no readable drift. However, our plots of the N6A’s solution slowly began to indicate that even though our course was straight, the MK 19 was no longer northseeking but directional and we were now steering a “grid” course which would carry us slightly to the right of the spin axis of the earth. We checked this solution against our other directional gyros and anticipated current data. These confirmed the auto-navigator’s solution and in two increments course was changed 3° to the left.
Now all solutions agreed that we would “pierce the pole,” to use the words of one of the engineers aboard. The fact that a northseeking compass did take the ship to a point 60–100 miles from the Pole and at that point would have by itself provided information to take the ship within normal navigational accuracy of the Pole may seem amazing to outsiders. We aboard, however, expected this type of performance from the MK 19 as a result of our previous Arctic experience with the compass and its everyday reliability since then. Even though it had already outperformed the expectations of many, it still failed to show any readable drift rate and was an outstanding DG. My position report to the Captain showed the compass to be reading 357° when in reality our course was 000°T. It must be realized that this apparent error was not due to a drift, but to the fact that the MK 19 was then a DG and we were steering “grid” courses. By the same token a few seconds after crossing the Pole it still read 357° and we were automatically on 180°T, again a difference not due to compass drift.
We have been asked many questions about whether or not compasses spin around at the Pole. Even though they do not, several interesting things do happen. All normal heading references continue to indicate a northerly course even though at that time course becomes southerly. This makes no difference as it is simply a matter of converting heading by steering repeater to true course by applying 180° plus, or minus any other known difference. Sometime after heading away from the North Pole however the north-seeking gyro would again feel a force to precess it towards the true meridian. Since this was anticipated, shortly after the crossing steering was shifted to a straight DG. The MK 19 was secured, slewed 180°, and restarted. It would now only be required to precess 1° or 2° at the most to the true meridian. After our master gyrocompass was again settled on the meridian, we set a grid course for the Greenwich Meridian, and thence for the open water between Spitsbergen and Greenland.
On the morning of August 5 we were clear of our ice canopy and surfaced. It was only a matter of a short time before we had a sun sight and were converting it to a line of position. This line confirmed our belief that our position was in the ball park and that in fact we were in the Greenland Sea. Some 86 minutes later I took another sun line to obtain a running fix, our first fix since Alaska. Our position by Inertial Navigation and our Estimated Position from gyrocompass and log information were both within ten miles of this fix. I reported the results to the Captain. We submerged and headed for Iceland.
Conclusions
Sufficiently accurate and safe navigation in the Arctic Ocean up to and including navigation at the Geographic North Pole is a reality using present day equipment, both conventional and inertial. The Nautilus on the first trip went out of her way to avoid maneuvers at the Pole. Now that we have seen what the equipment will do and have operating experience, we would not hesitate to operate in an unrestricted manner in these waters. Certainly much remains in the field of shipboard polar navigation. We must work toward making all equipment operate in a routine manner and pursue navigation by other methods, such as explosive echo ranging and bathymetry. Even though it has been proved that navigation in extreme latitudes is possible, much hard work and study remain before such operations become routine.
★
Up Periscope
Contributed by Captain Bailey Connelly, USN (Ret.)
The submarine S-28 was cruising at sea off Lower California and, being off soundings and out of sight of land, the Captain was taking an afternoon nap. Besides the OOD and helmsman on the bridge, there were the Chief Machinist and the Chief Electrician. The latter was sitting on the periscope shears and was wearing a tightly buttoned submarine jacket.
When the Captain awoke he decided to take one of his numerous navigational cuts and walked into the control room and pushed the periscope button. It came up fast, slipped neatly under the Electrician’s jacket and carried him aloft. As he shot upward with hands and feet flying and making a great amount of noise, the Chief Machinist hung on to his foot and accompanied him part way.
I yelled through the open hatch and the periscope was promptly lowered, leaving the Electrician momentarily defying the laws of gravitation, it seemed.
Thereafter he continued to eat his meals on the bridge, but standing.
★ ★ ★
Camouflage Expert
Contributed by John F. McNeil
During a period of relative quiescence aboard our APA, the La Salle, our Deck Division Officer (a former artist and recent graduate of V-12 training) decided that the camouflage paint covering our LCVP landing craft was nothing short of monstrous and should be retoned. He further added with a note of disgust that the decorations left by the gulls and sea terns did nothing toward improving the color scheme, and insisted that we chase the birds off each time they landed.
Calling the Chief Boatswain’s Mate to the wardroom, the division officer gave a lengthy dissertation on painting, going into great detail about toning, color combination, and the bird problem. A veteran of some 25 years’ of service, the Chief said nothing during the entire discourse. The officer. finally concluded with, “Do you understand what I want, Chief?”
Without hesitation the Chief replied “Yes, Sir, I’ll see that no tern is unstoned and that no stern is untoned.”
(The Naval Institute will pay $5.00 for each anecdote accepted for publication in the Proceedings.)
