Correcting Flaws in the Art of Navigation

by QMCM Byron E. Franklin, U.S. Navy (retired)

From U.S. Naval Institute Proceedings, July 1987

Despite the efforts of the Navy to improve the proficiency of its piloting teams, an insidious, built-in deficiency in the practice of navigation in hazardous pilot waters will persist until the Navy's higher echelons and training schools recognize the problem and take corrective action. The problem is that, generally, we believe that we have to live with navigation triangles— triangles of error. This comes from the attitude that point fixes, or small triangles, are just luck, or that they are textbook exercises not related to the real world. This may be true in celestial navigation, but not in piloting.

This attitude is induced by navigation texts and training courses, which, when treating the cross-bearing plot, state that one should take the center of the triangle as the fix. Some books and courses go in to state that one should use trial and error to remove constant error when the triangle is uncomfortably large.

Actually, one must accept only the smaller triangles of error. To avoid making bad recommendations based on the large triangles, one needs only to apply the Franklin Piloting Technique (see Nathaniel Bowditch, American Practical Navigator, 1977 edition, Volume I, Article 1009, Pub. No. 9). This provides a less confusing and more accurate plot on which to base recommendations.

Paradoxically, considering the flawed attitude, the plotting team puts a lot of effort into trying to collapse the triangle on the next round of bearings... and the next... This efficient effort requires so much of the navigator's (and his plotting team's) attention that other important matters are neglected. There is much more to piloting than just being able to produce a high-quality cross-bearing plot. Even with a good plot, sound recommendations to conn require considerable knowledge and experience. The experienced navigator who is aggravated by the quality of his plot cannot perform up to his potential. He will be unable to stay ahead of the immediate situation and will be unprepared for the unexpected.

Another way training materials contribute to the flawed attitude is in their treatment of error specifications. The error specifications of certain gyrocompasses indicate that their use as a heading reference in cross-bearing plotting will result in a triangle even when there are no small random errors in the bearing observation. In the treatment of azimuths of the sun for finding gyro error, most navigation texts and training materials state that if the error is calculated to be 0.5°, it can be considered zero. No doubt this reflects certain errors made in observations and in rounding off errors, particularly when tables are used for the calculation. However, after the ship gets under way and is subjected to accelerations that affect the gyro and for which the gyro imperfectly compensates, the error could become greater.

Perhaps too little attention is given to the fact that an azimuth of the sun is a crude way to check for gyro error. One of many factors affecting the precision of this method is the somewhat thick band of reflected light from the sun. Although not a common problem, the mirror of the azimuth circle could be out of alignment. If so, it could indicate that there is no gyro error, but leave you with large triangles when you shift to the bearing circle and plot on the chart. From my experience, it is unwise to use the azimuth circle to find and correct the gyro system error.

After having just arrived on board an aircraft carrier as senior chief Quartermaster, I found the gyro error to be 1.5° east by using the Franklin Piloting Technique. The azimuth placed the error at nearly zero. To plot with pinpoint accuracy, we used the 1.5 ° east error correction and did not adjust the gyro until sophisticated triangulation from the beach agreed with the 1.5° error and, of course, disagreed with the azimuth. I took the ship's azimuth circle to the tender where the 1.5° error was detected in the circle. Apparently, the yard/overhaul had used the faulty azimuth circle to align the system. This was not the first time I had run into this problem. But it was the last time that an azimuth of the sun was given precedence in determining gyro error in any ship that I served that had navigation aids.

From 1959, when I began developing my system, until I retired in 1978, I encountered no gyro problems that I could not solve quickly and mechanically. My system also helped others on more than one occasion. For example, a unit commander became troubled by small triangles passing over a string of buoys on the chart made by his very competent people. His fatih in the navigational skills of a new submarine's crew prompted him to have the position of the buoys checked. The conn had stated that they went down the middle of the channel. Using my technique, I quickly established that, indeed, the sub had the gyro error noted by the triangles, and did go down the center of the channel as conn stated.

Another navigational flaw is the failure to consistently analyze problems encountered during a transit of hazardous waters. Unfortunately, the charts in use are too quickly erased and stowed for future use. This practice should be changed to prevent the same mistakes from being made over and over. This need not be done immediately after transit. The charts and associated records could be set aside until operations permit their inspection and evaluation.

Generally, it may be true that somewhat sloppy work will not endager the ship. Inevitably, however, the time comes when a more accurate plot is absolutely necessary. Each transit should be used as a training exercise for difficult transits; the goal should be high-quality piloting at all times. Addressing these two navigational deficiencies will result in more accurate plots, more time to stay ahead of the navigational big picture, and the opportunity to benefit from prior mistakes.

Master Chief Franklin was a quartermaster for 26 years on various surface ships and nuclear submarines, before retiring in 1978. Two navigation techniques bearing his name— the Franklin Piloting Technique and the Franklin Continuous Radar Plot— are currently published in navigation texts and training materials. He is the author of articles 1006-1009 of Nathaniel Bowditch's American Practical Navigator (1977 edition), the Quartermaster First Class and Chief training courses, NavEdTra 10151-D1; and the Radar Navigation Manual, pages IV-24 and IV-25. He also co-authored two articles, "The Franklin Piloting Technique" and "Navigation Planning," for The Journal of the Institute of Navigation. He was awarded with the Navy Commendation Medal for his work with the Naval Oceanographic Office in piloting, as well as in radar, celestial, and radio navigation evaluation and recommendations.

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