Three Hundred Things a Bright Boy Can Do

by Unknown

We may divide the rocks thus encountered in fast water into two classes—(1) Those that are sunk, so that the boat may possibly float over them, and which do not deflect the direction of the surface current. (2) Those that are breakers, and so deflect the current, and do not allow the boat to float over them. The currents may be divided into—(1) Those that are equable in force, and in the same direction through the course to be steered. (2) Those that alter their direction in a part of that course.

In the problems before the canoeist will be found the combinations of every degree and variety of these rocks and currents, but the actual circumstances he has to deal with at any specified moment may be generally ranged under one or other of the six cases depicted in the accompanying woodcut. In each of the figures in the diagram the current is supposed to run towards the top of the page, and the general course of the canoe is supposed to be with the current. The particular direction of the current is indicated by the dotted lines. The rocks when shaded are supposed to be sunk, and when not shaded they are breakers. Thus the current is uniform in Figs. 1, 2, 3; and it is otherwise in Figs. 4, 5, 6. The rocks are all sunk in Figs. 1, 2, 3, and 5; whereas in Figs. 4 and 6 there are breakers. The black line in all the figures shows the proper course of the centre of the boat, and it is well to habituate oneself to make the course such as that this line shall never be nearer to the rock than one-half of the boat’s length.

The simplest case that can occur is when the canoe is merely floating without “way” through a current, and the current bears it near a rock. If this be a breaker, the current, being deflected, will generally carry the boat to one side. The steering in such cases is so easy, and its frequent occurrence gives so much practice, that no more need be said about it. But if the rock be a sunk rock, and if it be not quite plain from the appearance of the water that there is depth enough over the rock to float the boat, then it is necessary to pass either above the rock, as in Fig. 1, or below it, as in Fig. 2.

A few days’ practice is not thrown away if the canoeist seizes every opportunity of performing under easy circumstances feats which may at other times have to be done under necessity, and which would not be so well done then if attempted for the first time. Let him, therefore, as soon as possible, become adept in crossing above or below a single sunk rock with his boat’s bow pointed to any angle of the semi-circle before him.

Next we have to consider the cases in which more than one rock will have to be avoided. Now, however great the number of the rocks may be, they can be divided into sets of three, and in each of the figures 3, 4, 5, 6 it is supposed that (for reasons which may be different in each case, but always sufficient) the canoe has to pass between rocks A and B, and then between B and C, but must not pass otherwise between A and C.

In Fig. 3 the course is below B, and above C, being a combination of the instance in Fig. 2 with that in Fig. 1. The precise angle to the line of the course which the boat’s longer axis ought to have will depend upon what is to be done next after passing between B and C, and hence the importance of being able to effect the passages in Fig. 1 and Fig. 2, with the axis at any required angle.

We may next suppose that one of the three rocks, say B, as in Fig. 4, is a breaker which will deflect the current (as indicated by the dotted stream lines), and it will then be necessary to modify the angle of the boat’s axis, though the boat’s centre has to be kept in the same course as before. It will be seen at once that if A were a breaker the angle would be influenced in another manner, and that if C were a breaker the angle at which the boat should emerge from the group of rocks would be influenced by the stream from C also; but it is only necessary to remind the reader that all the combinations and permutations of breakers and sunk rocks need not be separately discussed,—they may be met by the experience obtained in one case of each class of circumstances.

Fig. 5 represents a circular current over the group of three rocks. This is a very deceptive case, for it looks so easy that at first it is likely to be treated carelessly. If the boat were supposed to be a substance floating, but without weight, it would have its direction of motion instantly altered by that of the current. But the boat has weight, and as it has velocity (that of the current even if the boat is not urged also by the paddle so as to have “way” through the water), therefore it will have momentum, and the tendency will be to continue the motion in a straight line, instead of a curve guided solely by the current. In all these cases, therefore, it will be found that the boat insists upon passing between A and C, where it must not be allowed to go (on the hypothesis we have started with), and if it effects a compromise by running upon C, that will be by no means satisfactory. This class of cases includes all those in which the river makes a quick turn round a rock or a tongue B, where the boundary formed by the rock A on the outer bend of the stream is a solid bank, or a fringe of growing trees, or of faggots artificially built as a protection against the erosion of the water. This case occurs, therefore, very frequently in some fast rivers, say, at least, a hundred times in a day’s work, and perhaps no test of a man’s experience and capacity as a canoeist is more decisive than his manner of steering round a fast, sharp bend. The tendency of the canoeist in such cases is always to bring the boat round by paddling forward with the outer hand, thereby adding to the “way,” and making the force of the current in its circular turn less powerful relatively. Whereas, the proper plan is to back with the inner hand, and so to stop all way in the direction of the boat’s length, and to give the current its full force on the boat. Repeated lessons are needed before this is learned thoroughly.

The case we have last remarked upon is made easier if either A or C is a breaker, but it is very much increased in difficulty if the rock B is a breaker or is a strong tongue of bank, and so deflects the current outwards at this critical point. The difficulty is often increased by the fact that the water inside of the curve of the stream may be shoal, and so the paddle on that side strikes the bottom or grinds along it in backing.