INTERNATIONAL (COMMERCIAL) CODE OF SIGNALS

B

C

"CODE SIGNAL" AND "ANSWERING PENNANT."

H

P

W

A

RUDIMENTARY TREATISE

ON

NAVIGATION

PART I.-HOW TO KEEP THE LOG AND WORK IT OFF
PART II.-ON FINDING THE LATITUDE AND LONGITUDE

BY JAMES GREENWOOD, B.A.

OF JESUS COLLEGE, CAMBRIDGE

TO WHICH ARE ADDED

THE DEVIATION AND ERROR OF THE COMPASS; GREAT CIRCLE
SAILING; THE INTERNATIONAL (COMMERCIAL) CODE OF
SIGNALS; THE RULE OF THE ROAD AT SEA; ROCKET
AND MORTAR APPARATUS FOR SAVING LIFE;
THE LAW OF STORMS; AND A BRIEF

AND

DICTIONARY OF SEA TERMS

WITH NUMEROUS WOODCUTS

COLOURED PLATES OF FLAGS

NEW, THOROUGHLY REVISED, AND MUCH ENLARGED EDITION

By W. H. ROSSER

AUTHOR OF THE "DEVIATION OF THE COMPASS CONSIDERED PRACTICALLY,"
"THE YACHTSMAN'S HANDY-BOOK FOR SEA USE," ETC. ETC.

LONDON:

PRINTED BY VIRTUE AND CO., LIMITED,

CITY ROAD.

PREFACE.

The Sailor's Sea-book was not written for the purpose of supplying any deficiency in works treating of the same subject. Its object was merely to assist a Yachtsman or Master who, with the intention of conducting his vessel safely to her destination, deemed it preferable to know a little of Navigation perfectly, than all its branches indifferently. This purpose, amidst many additions and alterations in the new edition, has never been lost sight of.

The Navigation is divided into two parts:—

I. How to keep the Log and work it off;—in other words, to keep the Dead Reckoning.

II. To find the Ship's Place by Observation, that is, the Latitude by a Meridian Altitude of the Sun, and the Longitude by Chronometer and Sun's Altitude; together with the Deviation and Error of the Compass.

Too much space was formerly given to the method by projection, a mode of working out problems in Navigation never adopted by the practical seaman, who uses the Traverse Tables and Logarithms, together with a few other short tables of easy reference. By the aid of the Traverse Tables he gets his position by Dead Reckoning: by the aid of the other Tables and the Nautical Almanac—when he knows how to use the Sextant and Chronometer—he finds his position from Observation.

If he is a careful navigator he also