Mariner's Guide to Nautical Information
  • Home
    • Purchasing
    • Reviews
  • Updates
  • New Links
  • New Publications
    • Articles
  • Blog
  • More . . .
    • Corrections
    • Contact
    • About the Author

Why bother with dead reckoning these days?

1/21/2013

0 Comments

 
Do you know what dead reckoning is and how to use it? DR is used to calculate a boat’s position along an actual or proposed course line, using the time underway and the speed of the vessel. With GPS on so many boats, people don’t seem to bother much with dead reckoning arithmetic these days, because the GPS can easily calculate time, speed, and distance while navigating toward a waypoint. Dead reckoning is used to plan a trip and to keep track of your progress independently of the boat’s instruments.

Use DR calculations to double check your boat’s position visually and on the chart. Use DR calculations to determine when you should be able to see a particular aid to navigation or landmark based on your boat’s speed and present position. Can you answer the following DR questions? (1) What speed must I maintain to go 45 miles in the six hours before it gets dark? Speed = distance divided by time. (2) The top speed of my boat is about 12 knots; how far can I go in 10 hours? Distance = speed x time. (3) My boat’s average speed is 8 knots; how long will it take me to travel 130 miles?  Time = distance divided by speed.

If these little problems are easy for you, it will be a snap to keep a DR plot on the chart or in a log, so you have a backup to your electronics. For the arithmetically-challenged you can buy an inexpensive flat, plastic device called a nautical slide rule, to do the calculations visually. Weems and Plath product #105 is one model. No batteries needed and no formulas to remember!
0 Comments

Carbon monoxide detectors save lives

1/12/2013

0 Comments

 
Some people have carbon monoxide (CO) detectors in their homes, and it’s a very important safety item aboard a boat that has an inboard engine or generator, and/or a non-electric heating device (kerosene, propane or other gas, or a solid fuel heater). Carbon monoxide is deadly. Choose a marine CO detector/alarm; it is designed for the marine environment and it’s less prone to false alarms than home detectors used on a boat. Install the detectors (larger boats need more than one) according to the manufacturer’s directions. Do some research before buying and installing a CO detector/alarm.
0 Comments

    Author

    Priscilla Travis spends more than 110 days each year on the water, takes photos, and writes about nautical topics.

    Archives

    October 2015
    September 2015
    August 2015
    July 2015
    November 2014
    May 2014
    February 2014
    January 2014
    December 2013
    November 2013
    October 2013
    September 2013
    July 2013
    May 2013
    April 2013
    March 2013
    February 2013
    January 2013
    December 2012
    November 2012
    October 2012
    September 2012
    August 2012
    July 2012
    June 2012
    May 2012
    April 2012
    March 2012

    Categories

    All
    Compass
    Crew & Health
    Education And Training
    Electronics
    Lines & Knots
    Maintenance
    Miscellaneous
    Navigation
    Navigation Rules
    Navigation Rules
    Radio
    Safety
    Seamanship
    Spoken Language

    RSS Feed

DISCLAIMER: The information and advice on this website constitutes personal opinion, and must be understood as such. It’s offered to enhance public knowledge and promote a better understanding of nautical topics. It must never be considered a substitute for professional legal, medical, safety, or other advice.