General Plans of USS KAWISHIWI AO-146
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Note from Radarman

In the CIC area, it shows some Radarmen standing next to and leaning on what was called the Dead Reckoning Tracer( The Big rectangular looking "box"). We would use this to track our location anywhere at sea. It had a glass top, and inside this were small gears that would be set to our starting location (Latitude and Longitude) right before we would get underway. As soon as the ship was underway, the gears would slowly start to move, and the DRT , as it was called, also had a small minute light that would beam up to the glass top a very sharp circular dot; we would tape a chart covering the area we would be in to the top of the glass, and this minute, strong light would mark the place on the chart the ship would be in on the sea/globe. The small gears would always be moving to mark the ship's location. Although the DRT would mark our location almost to the "mile", it would not be exact, as it would not allow for "set" and "drift". In other words, if there was a current out at sea working against the ship's course and speed, this current would maybe set us back/ ahead a certain distance and speed per hour, and that's why the DRT had the name/word "dead" in it( Dead Reckoning Tracer) - it would show the ship's location based ONLY on the gears that were set and on the speed and course. It would not allow/show any offsetting locations of the ship based on "drift and set", but it was VERY close to it.
I remember one night we were sailing to Japan , and based on the DRT and the chart ( map) of the area we were in that was taped top the top of the glass on it, I saw the light underneath the glass and on the chart cross the longitude line on the chart that designated the longitude line separating one day from the other, telling us that we had just crossed the International date line; I of course reported this to the OOD and made a notation in the CIC log.


Click image at right for details >

The next morning some guys from other departments and a couple of "Lookouts" that night saw me in the chow hall, and had that look of amazement. They wanted to know how in the hell I knew when we had crossed the International date line the night before, as it was pitch dark and with nothing but sea all around the ship. I gave them a short explanation, and then they seemed satisfied.

I doubt very much if the DRT exists at all nowadays, as they probably have high tech units that show exactly where the ship is, by satellite, etc.electronically.
Hector Montano RD2 1960-62;  November 2008


Dead Reckoning Tracer Specifications: http://www.tpub.com/content/MIL-SPEC/MIL-D/MIL-D-2759E/

The dead reckoning tracer (DRT) device for the Multi-Mission Tactical Trainer (MMTT) is older technology and unsupportable, dating from the World War II era. From: http://www.mescorp.com/modified/tacticandoperator.html

Read: http://portal.acm.org/citation.cfm?doid=507546.507588


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