GPS Backup with a Mark 3 Sextant

by David Burch, Tobias Burch (Illustrator)

Overview

No power, and batteries used up? This book and an inexpensive Mark 3 sextant lets you carry on. Alternatively, if you want to learn a basic celestial navigation position fix for any reason with minimum investment, this book shows how to do that.

It's a short book, mostly tables. You can read it in an hour or two, master the sights in less than that, and find your position the next time you see the noonday sun.

Our guiding principle for this booklet was to provide a means of learning and executing a position fix at sea when a vessel has lost its GPS navigation. We wanted a solution that is compact and inexpensive, using tables and procedures that are easy to learn and use. This goal led to our proposing a minimum kit that mariners would not hesitate to add to their gear to cover the unlikely situation it would actually be needed. Mariners who cross oceans in small boats realize they must be self-reliant and cover all contingencies.

For mariners who do not have the opportunity to learn the full range of celestial navigation, this booklet and a Mark 3 sextant serve as an inexpensive backup that can be used to navigate across any ocean.
The almanac pages included have been custom designed to facilitate fast, easy solutions for Lat and Lon from the sun, plus we include a unique new Regiment of the North Star for easy Latitude by Polaris sights on any date.

This book includes a 60-page Almanac of the sun to provide quick and easy solutions for Latitude and Longitude, as well as a unique new method for finding the corrections needed to find Latitude by Polaris, as well as in depth discussion of how to use a Mark 3 plastic sextant with emphasis on reading the angle scales.

Contents
1. OVERVIEW 
2. SEXTANT SIGHTS WITH THE MARK 3 SEXTANT
     Reading the Sextant Scales 
     Adjusting the Index Mirror
     Index Mirror Adjustment Using Only a Sea Horizon
     Index Mirror Adjustment with a Star 
     Index Mirror Adjustment with Cloud Edges
3. TAKING SUN SIGHTS
     Aligning the Sun on the Horizon
4. A COOKBOOK APPROACH TO FINDING POSITION 
     Correcting the Sextant Height to get the Observed Height
     Finding Latitude and Longitude From the Sun
     The Recipe
     Finding the Peak Height of the Sun
     Finding the Time of LAN
     Sailing Under the Sun
5. WORKED LAN EXAMPLES
     Latitude Example 1
     Easy LAN Rule
     Longitude Example 1 
     Latitude Example 2
     Longitude Example 2
6. LATITUDE BY POLARIS
     Latitude by Polaris Example
7. PLOTTING POSITIONS AND DR TRACKS
     Setting Up a Universal Plotting Sheet 
     Using the Plotting Sheet 
     Getting by Without Dividers 
8. BACKGROUND INFORMATION 
     8.1 Timekeeping in Navigation 
     8.2 Lat, Lon, nmi, and DR
     8.3 Adjusting the Index Mirror on Land 
     8.4 Predicting the Time of LAN From Your DR-Lon
     8.5 Principles of the Noon Sight for Lat and Lon 
     8.6 Universal Rule for LAN
9. GPS BACKUP KIT--THEME AND VARIATIONS
10. REFERENCES
11. TABLES
     Sun Almanac
     Refraction Table, Dip Table, Polaris Table
     Increments Table

Product Details

BN ID:	2940161990513
Publisher:	Starpath Publications
Publication date:	07/25/2018
Sold by:	Barnes & Noble
Format:	eBook
Sales rank:	943,560
File size:	15 MB
Note:	This product may take a few minutes to download.

About the Author

David Burch is the author of 13 books on marine navigation and weather and the director of Starpath School of Navigation in Seattle, WA, which had more than 30,000 classroom students, before the school switched to exclusively online training. He has more than 70,000 miles of ocean experience ranging from the Arctic ice edge to Tahiti and Australia in the Pacific and from New York to Panama in the Atlantic. He has sailed across the Pacific to Hawaii ten times, three times winning the Victoria to Maui yacht race, and in 1984 setting the elapsed time record for that passage for vessels under 38 feet long (the record lasted 16 years).

In powerboats, he delivered a 65-foot fishing vessel from New York to Seattle, via Panama and has made numerous coastal deliveries between WA and CA, AK, and Mexico. He navigated the only American entry (72-foot Cassiopeia) in the storm-ridden '93 Sydney to Hobart yacht race and later navigated that vessel on the '96 Vic Maui and Swiftsure Lightship Classic when she won first overall in the latter.

His magazine articles have appeared in Cruising World, Ocean Navigator, Sailing, and Sea Kayaker. His column "Burch at the Helm" has appeared in Blue Water Sailing magazine since 2009. His textbooks and workbooks are used by numerous schools, nationwide.

His work has been recognized with the Institute of Navigation's Superior Achievement Award for outstanding performance as a practicing navigator, and by a USCG citation for his successful weather and vessel performance analysis used in a search and rescue operation. In February, 2011 he was awarded Fellow grade in the Institute of Navigation. In May of 2011 he named a Fellow of the Royal Institute of Navigation in London.

From 2005 to 2010, he has served as the editor of the quarterly newsletter of the Foundation for the Promotion of the Art of Navigation.

David is the author and developer of several software training programs, including the Starpath Radar Trainer, the world's most popular PC radar simulator and Starpath Weather Trainer Live, both used by individuals and schools, in several countries.

On the academic side, he is a past Fulbright Scholar with a Ph.D. in physics.