Sailing directions are written to supplement the charts and preserve for the mariner a mass of information which otherwise would not reach him.
It is always well to pay attention to the current arrows, as they are a means by which the strength and direction of the tidal stream may be ascertained. The symbol of a tide rip should not be ignored by one in a small boat, as the conditions might be right to make them dangerous.
On the water areas of the chart we find contours of depths as on the land are contours of height. It is a good scheme, if one wanted to take the trouble to run a contour line indicating a depth a few feet greater than the draft of his boat, and tint the shallow water with a brush.
Large vessels of deep draft upon approaching the coast are guided by the ten-fathom curve unless the shore is very steep-to and the water very deep. The masters of such vessels would remain outside that curve until their position was well established. Lighter draft vessels are guided by the five-fathom curve in a similar manner.
When approaching the land and the landmarks are not available, the character of the bottom further assists the mariner as he sounds slowly towards the land. The kind of bottom is indicated by abbreviations which are obvious on almost every portion of the charts.
The three-fathom curve is the most important to the greatest number of navigators and for this reason is made the most pronounced. In the majority of charts it is shown by a “sanded” area within it, but in many new charts it is heavily tinted.
In changing from one chart to another while working in an unfamiliar locality, take especial note whether the soundings are in feet or fathoms.
It is an excellent practice when a vessel is brought to anchor and cross bearings taken, to estimate the radius of her swinging circle by adding the amount of chain out to the length of the vessel and with this describe a circle on the chart and note if there is any danger of tailing into shoal water at any quarter.
This has been a long voyage and I am glad to tie up and let the printers take charge. If any of my readers see places where I have stood into the shallow water of inaccuracy, I will be grateful for a passing hail that I may shift helm and get out with as little damage as possible.