THE MANAGEMENT OF OPEN BOATS.
Small open boats must never be regarded as if they possessed th e qualities of deep and heavily ballasted yachts. They should not be sailed "gunwale under" as a small yacht is, and the puff or squall which a small yacht can be sailed through with impunity, will necessitate the open boat being thrown head to wind with head sheets eased up, or off the wind with aft sheets eased.
No system of ballasting will much increase the range of stability of a boat—(by boat is meant something of the type of the Surbiton gigs)—and it must be clearly understood that it is not the initial stability, or the stiff ness of the boat at small angles of heel upon which her safety depends, but upon her range of stability, that is to say upon the amount of stability or power to recover herself she has, when heeled to very great angles when the gunwale might be pressed under water. For competitive sailing, a boat to succeed must resist being heeled at all very potently, that is, she must have great initial stability, so as to be able to carry a large area of canvas without heeling more than to a point midway between her water line and gunwale. This stiffness is more dependent upon breadth of beam than upon the weight of ballast carried low, and an inexperienced boat sailer finding a boat very stiff at first might be tempted into pressing her beyond the danger point.
On the other hand, depth of hull of itself does not add to stability, but by ballasting it does, and lengthens out the range of that stability so that a boat may always have righting power at any possible angle of heel, providing she does not fill with water and sink : (see pages 8 and 42.) Thus safety does not so much depend upon the great stiffness which enables a boat to carry a large press of canvas without heeling to any con siderable extent, as upon the range of her stiffness or the continuation of that stiffness, even up to the time when she might be blown over on her beam ends. Now shallow open boats have a very low range of stability, and directly their gunwales are put under, they are likely to be blown over. A high side out of water in a large way increases the range of stability, and the higher, in reason, a boat's side is out of the water the safer she will be.
Boats are most frequently capsized in disturbed water, and the cause is generally ascribed to a sudden squall, or to the fact that the boat being unduly pressed, some of her loose ballast shifted to leeward. But a boat among waves might be, and no doubt frequently is capsized without any accession of wind or movement of the ballast.
It can be supposed that a boat is sailing with a beam wind, and with a beam sea, and that her inclination, due to the pressure of wind on her sail is 15°. If she got into the position shown in Fig. 48, she would practically be inclined to 30° and she would probably upset. Assuming that the boat had no sail set, she would not get into such a position, as she would accommodate herself to the wave surface and her mast would correspond to the perpendicular drawn to the wave surface (see Fig. 48). Even with sail set the boat would more or less so accommodate herself to the wave surface, minus her steady angle of heel ; but the increased pressure on the canvas, due to the righting moment of the boat, which would have to be overcome, would prevent her recovering herself entirely. That is, if the boat be heeled to 15° relative to the horizon, or to the normal surface of the water represented by the vertical line, and a wave came to leeward as shown, she would be in the position of a heel of 30° relative to the perpendicular to the wave surface ; but, inasmuch as the wind pressure is only capable of heeling her to 15° the boat would ultimately recover herself to that extent, and her mast would be represented by the vertical.
However, long before a boat could so recover herself, she might be swamped or blown over.
With a beam sea a boat will roll a great deal, and this condition is a prolific source of accidents. If a boat is being sailed at a permanent angle of heel of 15°, and by the action of the wave she is made to roll another 15°, she will frequently be in the position of being heeled to 30° ; and if the extreme part of the roll should occur jointly with such a position as shown in Fig. 48, the boat would inevitably upset.