NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Measuring time in small boat CN: what devices do you recommend?
From: Chuck Taylor
Date: 2004 Jan 7, 17:34 -0800
From: Chuck Taylor
Date: 2004 Jan 7, 17:34 -0800
--- Jim Thompson wrote: > > Digital watches are hard to read in winter air: the > LCD screen fades in the cold, ... Both Timex and Casio sell digital and analog quartz watches that light up with a bluish glow when you press a button. > 1. For timing sights on deck: a stopwatch with > split-seconds? Digital wrist-watch? Two suggestions: 1. Use a stop watch that will take "splits" or "lap time". You record the exact time at which you start it (the "start time"). Then when you press the appropriate button it records the lap time and keeps running. You can then read it and record it at your leisure, along with the sextant altitude. When you are ready for the next sight, repeat the process. 2. Use a tape recorder. Before you go out on deck, start the recorder and record the start time (e.g., "Ready, mark, time 17 hours zero minutes and zero seconds.") Leave it running as you take your sights. For each sight, speak into the recorder, saying something like, "Ready, mark! Altitude 33 degrees 42.5 minutes". No need to look at the time. Afterward in a well-lit room or cabin, play back the tape and time the intervals between the starting mark and each subsequent mark. Add those intervals to the start time and you have the times of your observations. > 2. For a chronometer to keep safe below decks as a > reference for the comparing watch: The GPS? I prefer a shortwave radio tuned to WWV (2.5, 5, 10, or 15 MHz). A GPS will suffice, but some older models do not take into account leap seconds. Once you check a GPS against an accurate time signal, it should be fine. Ashore you can get a good time hack at http://www.time.gov Good luck! Chuck Taylor 47 deg 55.2 min N 122 deg 11.2 min W __________________________________ Do you Yahoo!? New Yahoo! Photos - easier uploading and sharing. http://photos.yahoo.com/