The Lifeboat & its Work – Part 11

As a Life-boat has, in the majority of cases, to be propelled by oars, and as, in order to rescue a shipwrecked crew, she has generally to be rowed to windward against a heavy sea and strong wind, it follows that too much care cannot be taken to place in the hands of her crew the most efficient instrument for the performance of their laborious and perilous work. 

There are three valuable properties to be considered in oars for Life-boats, viz., lightness, stiffness, and strength ; and if all three were of equal value there would be no difficulty in arriving at a decisive conclusion as to the fittest description of wood for a Life-boat’s oars, after testing a sufficient number of each sort. The question is not, however, quite so simple, and must after all remain a matter of opinion to some extent, as the above-named properties have different values, and even all practical rowers may not agree as to the relative value of each. We will remark on the three above-stated properties in succession. 

1. Lightness

It is of the utmost importance that a Lifeboats oar should be as light as possible, consistent with strength for, however well-balanced an oar may be, a greater effort must he required to move a heavy than a light one, and, in proportion, the sooner will a person become fatigued in rowing with the one than with the other ; and, as a Life-boat man will frequently have to make many hundred, and sometimes several thousand strokes with his oar before he gains his object, three or four pounds extra weight, like the last pound on the camel’s back, may cause him to break down altogether. Since, therefore, an oar being heavy or light may make the difference of a rower retaining his strength of arm or not, and of reaching a wrecked vessel or not, too much attention cannot be paid to secure the greatest possible lightness, in conjunction with adequate strength.

As the only suitable woods for the making of oars are different species of fir and ash, and as all fir woods are lighter than ash, it follows that, in this respect. fir oars are to be preferred for Life-boat service. 

2. Stiffness

A stiff oar is considered to be more manageable in a rough sea than a pliant one, although in smooth water many men prefer rowing with pliant oars, especially those who have been accustomed to their use. 

It is commonly supposed that there is a loss of power in rowing with a pliant oar, a certain portion of the force applied being expended in bending the oar. Such, however, is only to a slight extent the case, as no force once exerted can be absolutely lost ; and the oar itself, in its effort to recover its normal condition of straightness before being withdrawn from the water, will continue the force first imparted to it after it has ceased to be made, in the same manner that a spring-board, in recovering its straight direction, enables a person to jump to a higher altitude or farther distance than he otherwise could ; the oar, in fact, merely acting as a medium for applying the force in an unequal and more prolonged manner. A slight degree of pliancy in an oar is probably, therefore, not a disadvantage, although much pliancy would be. 

3. Strength

It will no doubt be supposed by most persons that an oar cannot be too strong, and that, therefore, great strength is the most important element in a Life-boat’s oar. Up to a certain amount of strength, such is the case, and every oar in a Life-boat should be so strong that the most powerful man could not break it in rowing but beyond that amount, independently of unnecessary strength involving greater weight, it becomes a question whether additional strength may not be a positive, and possibly a serious, disadvantage, even to the extent of endangering ·the safety of a boat. 

The most frequent cause of the breaking of oars in a Life-boat is her being struck by a broadside surf, when the lee gunwale being forced under water, the men on that side cannot raise the blades of their oars sufficiently high to prevent their becoming immersed : in that case the pressure of the water on the blades, as the boat is being carried, broadside on, at the rate of several miles an hour, before the sea, is so great that the oars are forced from the rowers’ ·hands, and retained in a nearly upright position, with the blades several feet below the bottom of the boat. If the boat be in shallow water, they then come in contact with the ground, and are instantly broken, whilst, if in deeper water, they also often break ; and if from their great strength they were not to break, the strain on them is then often so great that they would wrench the thole-pins out of their sockets, and break the gunwale of the boat; or, if the latter were too strong to give way, the risk of the boat upsetting would be much increased, as the pressure of the still water on the blades of the oars beneath the boat, and that of the crest of the sea on her upper side in the opposite direction, would powerfully tend to upset the boat. 

In selecting the most suitable description of oar for a Life-boat, we have then to decide on a maximum of desirable strength, and on a limited flexibility or pliancy, and to select the lightest description of wood that possesses those properties. An oar is a simple lever, of what is termed the second order, that is, wherein the weight or body to be moved lies between the fulcrum and the motive power ; the water being the fulcrum of the lever, the gunwale of the boat the point at which its power is applied to the moving body or weight, and the rower’s arms being the source of power.

The length of an oar must of course be proportional to the width of the boat, and it should be so poised on the gunwale that the rower can raise or depress it or move it in any direction with the smallest effort. An oar should be not less than five inches wide in the blade, or it will expose so small a surface to the water as to cut through it, and so work on a too yielding fulcrum, with comparative loss of power.

The height above the thwarts, of the thole or row- lock in which the oar works on the gunwale, should be sufficient to enable the rower to lift the blade well above the waves by depressing the loom or handle ; but, on the other hand, it must not be so high as to require him to raise his arms above the level of his chest in rowing, in which case he will row with much less force, and be much sooner fatigued. A height of eight inches from the thwarts to the oar on the gunwale will be found a suitable average.

Lastly, the mode of confining the oar to the gunwale of the boat is of much consequence. The most common modes, in ordinary boats, are rowlocks and double pins, between which the oar works ; but as an oar is liable to jamb in the rowlock when rowing in a rough sea, and thereby to get broken, or to damage the gunwale, the oars of Life-boats have generally been worked in a rope grummet or ring, over a single iron thole-pin : a further advantage of this plan is, that it enables the oars to lie along the outside of the boat when not in use, and thus saves the necessity of unshipping them and getting them in-board on going alongside a wreck, which is a great advantage.

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