The Book of the Sailboat: How to rig, sail and handle small boats

by A. Hyatt Verrill

All of these safeguards of the sea would be of little value to mariners, however, if it were not for charts, for no man could remember all the various buoys, beacons, range marks, lightships and lighthouses of the coasts and the various harbors.

To enable the seaman to know just what every one of these means, and to help him find his way in places where he has never been, charts are furnished by the government. These are maps which show all the buoys, lights, signals and other guides and also indicate the depth of the water, the kind of bottom, the points of the compass, the prominent landmarks, the rise and fall of tides and the outlines of the shores.

With the aid of a chart a sailor can safely find his way into any harbor or along any coast, and even if it is some remote place where there are no lights or buoys, or if the weather is too thick to enable him to see the buoys or lights, the charts will tell him where he is by the character of the bottom and the depth of the water.

It may seem queer to think of a sailor navigating a vessel by the bottom of the sea, but it is a method very widely used and of great importance.

In nearly every place the bottom varies more or less and the waters shoal in a certain way and by finding the kind of bottom there is and the depth of the water the seaman identifies the locality he is in. Thus, if the bottom is white sand and the depth is five fathoms, he looks upon the chart and finds the spot where a similar depth and bottom is indicated. Perhaps there are several such spots and the sailor is not sure which one he is on. In that case, he looks in the direction he is sailing and finds that on the chart the water shoals very gradually and that blue mud exists just beyond the spot where he thinks he should be. If his next sounding shows blue mud and only a little less depth than before he knows he is right, whereas if it shows deeper water and gravel, or much shallower water and sand, he knows he is off his course and by comparing his soundings with the chart he can tell just where he is.

To determine the depth of water, a sounding line is used with a heavy lead weight at the end and with the fathoms marked upon the line and every time the lead is dropped to the bottom a tiny sample of the bottom is brought up sticking to a little tallow which fills a recess in the end of the lead.

Nowadays there are many improved forms of sounding lines and leads, some of which have very cleverly arranged appliances for bringing up samples of the bottom, but the old-fashioned line and lead is still widely used.

Still other important items which are indicated on the chart are bearings or landfalls. Often some prominent cliff, hill, mountain or other object is visible long before the shores themselves or any lights can be seen, and by bringing certain such marks in line, or by obtaining the direction which they bear to the ship and then referring to the charts, the sailor can tell just what part of the shore he is approaching and how he should steer to enter a harbor or channel.

But charts, bearings or landmarks would be almost useless without that most important of all mariners’ guides, the compass.

Everyone who uses a boat should know how to use a compass and every boat, save the very smallest open boats, should invariably have a compass on board. Even if you never expect to sail far from shore you may some day be caught in a thick fog or blown off to sea for several miles and a compass may save your life and the lives of others. But unless you know how to use a compass this useful instrument will be of little aid. It may seem strange to speak of learning to use a compass for everyone knows that a compass points toward the north, but when an ordinary compass is used on a boat the conditions are very different from using a compass on land. In the first place it is not enough to know the cardinal points of north, south, east and west, for while such general directions may serve on the land, a very slight variation of the course may result in running on a reef or in missing a harbor, when sailing. For this reason you should become thoroughly familiar with all the points of a compass and should be able to box the compass or repeat all the thirty-two points from north around the circle to north and back again without looking at the compass. Then you should learn the quarter points and should be able to tell at a glance whether the boat is heading north-one-quarter-east or is a quarter of a point off her course in any direction, for a quarter-point error in sailing may make a vast difference at the end of a few hours’ run.