LIFE-BOAT OARS.

As a life-boat has, in the majority of eases, 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 ranch care cannot betaken to place in the hands of her crew the most efficient instrument for the performance of their laborious as well as hazardous work.

The oars of a life-boat, except in the case of a few large boats that are worked exclusively by sails, have therefore always been considered the chief part of her furniture, and the greatest pains have been bestowed on their construction, and in the selection of the best material from which to make them.

From the first introduction of life-boats, at the end of the last century, fir bars have been used in them, it having been considered that ash oars were too limp and too heavy.

Thus, in a description of the Shields lifeboat in the edition of Campbell's " Lives of British Admirals," published in 1817, vol.

viii., the following passage occurs:— " The oars she is equipped with are made of fir of the best quality, it having been found by experience that a rove ash oar which will dress clean and light, is too pliant among the breakers; and when made strong and heavy, from rowing double banked, the purchase being short, it sooner exhausts the rower; and this makes the fir oar, when made stiff, preferable." In consequence, however, of the frequent breaking of the oars in the life-boats of the NATIONAL LIFE-BOAT INSTITUTION, the attention of the Committee of Management has been recently directed anew to the subject, and by their direction a number of oars, made of different descriptions of wood, have been tested to ascertain their respective qualities.

Although to obtain very accurate results, it would have been necessary to destroy a much larger number of oats, yet the table appended, showing the result of the trials, so far, may not be without interest. It will be seen that three properties are designated as of value, viz., lightness, stiffness, and strength; and if all three were of equal value, there would be no difficulty in arriving at a decisive conclusion RS 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 life-boat's oar should be as light as possible, consistent with strength; for, however well-balanced an oar may be, a greater effort must be 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 his object is attained, 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 hence of reaching a wrecked vessel or not, too much attention cannot be paid to secure the greatest possible lightness, in conjunction, of course, 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 them. 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 further 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 gun wale 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 generally are so; 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 thowl-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 that effect.

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 analysis of Table I. (p. 188) shows that by far the strongest oars are those made of ash, but that they are also the heaviest; whilst if reduced in size to an equal weight with a fir oar, they would then be much more pliant, owing to the greater flexibility of ash wood.

Thus the lightest ash oar tested, of those made of uniform size, was 19 Ibs., whilst a weight of 2f cwt. suspended at 1 foot from the end of the blade, equivalent to three times that amount or 8i cwt. of force, applied at the handle, caused no less than feet of deflection without breaking the oar.

But the lightest fir oar, a Norway spar, of only 14f Ibs., broke on the suspended weight amounting to 1 cwt., 3 qrs., and 23 Ibs., equivalent to a force of 5 cwt., 3 qrs., and 13 Ibs. at the handle, whilst its deflection at 1J cwt. on the blade, equal to 4 cwt. at the handle, was 1 ft. 10 in.

Now there can be no hesitation in pronouncing the latter of these oars to be preferable to the former. No rower could have broken it by his own strength, without exerting a force equal to more than 4J cwt., which is much more than he could do: its liancy was not great, and with every motion of his arms, he would have had to move 3i Ibs. less actual weight than with the lightest ash oar.

On the other hand, if, as for the reasons above stated we believe to be the case, there is a limit to desirable strength, the greater strength of this, the lightest ash oar would have been an actual disadvantage.

It might, however, have been reduced in size and weight, but its pliancy would thereby have been much increased.

It will be observed, by Table III., showing the average quantities, that twelve descriptions of oars were tested, two of them being of ash, American (United States) and Quebec, and that ten descriptions were of fir of various sorts. If from the latter we reject American pitch pine and larch, on account of their weight and too great pliancy, Baltic yellow batten for its pliancy, Quebec yellow batten for its weight, and Quebec white spar for its deficient strength, we have remaining, from which to select, Norway and Baltic white spars and battens, and the peculiar wood the Oregon or Vancouver's Island pine. This latter wood has not hitherto been used for oars, but has been solely, we believe, imported for the masts of yachts, for which it seems to be peculiarly suited on account of its strength, cleanness, and freedom from knots, &c. A noble specimen of this wood, by far the longest and finest s,par in Europe, will be familiar to those who are acquainted with the Royal Gardens at Kew, where it has been erected as a flagstaff, and towers high above the highest elms and other trees that surround it; its length being 159 feet, and its-diameter only 19 inches at the base ; the tree from which it was made having been 220 feet high.

Of these five selected descriptions of wood, the Norway and Baltic white spars and battens are so nearly equal in value, that it would be necessary to test a large number of each to distinguish any perceptible difference in the average of those brought into the market, and perhaps either one of them may be as good as the others, but various lots of each may vary in quality, some being better and some worse. The oars made from spars (entire young trees) have generally been considered the strongest, and of those now tested, the strongest of the spar oars were stronger than those of the same wood made from battens or planks, but they are rather more uncertain, being apt sometimes to break abruptly at the knots.

The remaining wood, the Oregon pine, deserves special notice. It appears to be the strongest of all the descriptions of fir, and has the advantage of great uniformity of character, so that every oar may be depended on. It is free from knots, and breaks with a very long fracture. It varies in weight, according to the part of the tree from which it has been cut, the outside part of the tree being also heavier than the inner part. It is, however, much more expensive than any of the other kinds of wood, consequent on being brought from so long a distance.

Fir oars generally are said to deteriorate, as regards strength, from age, becoming, after many years, drier, lighter, and more brittle.

It will be noticed, in Table I., that some of the oars tested were served with spunyarn round that part of the loom which rests on the gunwale, that 'being the part where they most frequently break. It was thought that an oar might thereby be strengthened, but the "effect appeared to be rather the reverse, and those oars generally broke with a short or abrupt fracture close outside the " serving." The results of the testing so limited a number of oars, although attended with considerable expense, could only afford an approximate criterion as to their relative value. It is therefore proposed to supply a certain number of life-boats with oars of different descriptions, including ash, to be submitted to the test of experience and hereafter reported on. Some boats have already been supplied with oars made from he Oregon pine, for trial.

TABLE: I. — TRIAL of OARS at LIMEHOUSE, February and March, 1866. Length of each Oar 13J feet ; Diameter at thickest part of Loom 8| inches : "Width of Blade 5J inches. The Rest, representing the boat's gunwale, 3 feet 8 J inches from end of Handle, and 2 feet 11 inches from end of Loom. The weight suspended 1 foot from end of Blade. The Oars marked thus * were served round with spunyarn in the wake of the gunwale.

No.

1 2 3 4 5 6 7 8* 9 10 11 12 IS u 15 16 17 18 19* 20 21 22* 23 24* 23 26* 27 28 29* 30 31 32* 33 34 Description of Wood.

Oregon Pine, Timber Weight of Oar.

Ibs.

16 Ditto, ditto . . . 174 Ditto, ditto . . .

Ditto, ditto . . .

Ditto, ditto . . .

Norway Spar, White Ditto, ditto . . .

Ditto, ditto . . .

Ditto, ditto . , .

Norway Batten, White Ditto, ditto . . .

Ditto, ditto . . .

Ditto, ditto . . .

f Baltic (Swedish) Spar, White . J Ditto, ditto . . .

Ditto, Batten, White .

Ditto, Batten, Yellow f Baltic (Petersburg) ) 1 Batten, White. J Ditto, ditto . . .

Ditto, ditto . . .

Ditto, Yellow . . .

Ditto, ditto . . .

Quebec Spar, White .

Ditto, ditto . . .

f Quebec Batten,Yel- 1 low (Red Pine) .J Ditto, ditto . . .

American Pitch Pine Larch, Batten (Scotch) Ditto, ditto . . .

Ditto (English) . .

Quebec Ash . .

Ditto, ditto . . .

( American (S tates) ) 1 Ash, Red . . j Ditto, ditto, White .

18 201 19 20 15.; "i Deflection.

'" At iCwt inches.

7 si 7 61 5 6 7i 61 191 3i 151 174 16 16J 18 17 20| 20i "i 16} 161 174 17 15i - 151 191 20 20 20 181 211 231 24 20 19 6 44 5 4I 3i 61 6 61 6 51 *i 8 8 8 6 41 41 9 7 9 7 51 6 7 At iCwt.

ft. in.

1 li 0 Hi 1 11 1 1 0 10 0 9 1 4 1 1 0 91 1 0 0 10 0 10 0 101 0 8 1 11 1 0 1 01 1 0 1 0 0 91 1 5 1 31 1 10 1 5 0 9i 0 9i 1 41 1 5 1 9 1 2 0 7 0 HJ 0 111 1 21 At li Cwt.

ft. in.

1 7 I 6 1 8| 1 8 1 21 1 2 1 10 1 4 1 9 I 3 1 4} 1 11 1 71 2 11 1 8 1 71 1 8 1 11 2 5 2 21 . .

1 3 1 3 2 21 2 5 ..

1 11 1 01 1 61 1 7 1 10 At 2 Cwt.

ft in.

2 4J 2 11 2 4| 2 3f 1 8 1 10J 2 7 1 11 1 10 ..

2 6 ..

• • ..

1 101 ..

..

..

1 11 1 11 ..

4 31 3 2 1 6 2 3J 2 5 2 10 Breaking Strain.

cwt qrs. Ibs.

2 1 16 2 3 4 2 1 17 2 3 21 2 3 17 2 1 21 1 1 27 1 3 23 2 1 11 1 3 26 2 1 0 1 3 22 1 1 0 2 1 0 1 3 24 2 0 20 1 3 14 2 0 0 1 3 14 2 1 25 1 3 7 1 3 0 1 1 19 1 1 19 2 2 7J 2 2 13 1 3 7 Unbroken, 1 2 0 2 0 0 Unbroken.

3 2 21 3 0 0 Unbroken.

Length of Fracture.

ft in.

8 0 10 0 9 0 9 4 4 3 1 6 0 6 Abrupt.

6 6 4 0 4 0 2 4 2 0 2 0 Abrupt.

3 0 1 0 0 6 0 6 Abrupt.

2 0 Abrupt.

0 6 Abrupt.

[Jnderpart crushed only.

Ditto.

4 0 ..

Abrupt.

5 0 ..

0 9 (Sprung 1 only.

•• Position of Fracture from end of Handle.

ft. in.

8 3J 5 9 4 10 6 8 5 0 5 4 3 9 4 3 { 7 0 4 0 3 11 4 9 4 2 4 3 3 10 3 7 4 5 4 4 3 5 3 81 5 4 5 9 6 3 " 3 5 }4 5 6 2 5 3 "I 4 0 7 3 .. { 3 1 Sprung only.

- { Remarks, &c.

Strain across the grain of the wood.

With the grain.

Across the grain.

With the grain.

Ditto.

Broke short at the serving.

Broke at a knot.

At 2 cwt. Iqr. 81bs.

Reflection 51 ft.

Deflection at 4cwt.

51 feet.

At 3 cwt. deflection 51 feet.

At 2} cwt. deflection 54 feet.

OAUS WITH STOUTER LOOMS.

1 2 3 4 /Oregon Pine, Timber, 4 inches diameter .

f" Admiralty Pattern, 3| inches diameter.

}l3 6 ! 01 1 J ! (. Norway Spar, White. | ) i (Ditto, ditto, Swedish i 01 „, { Spar, White. . . fj l I * f Norway Spar, White, i ) „ , 4 inches diameter . ) 31 0 71 0 6 0 6 1 71 0 111 0 9J 0 8f 2 6 1 3 1 1 1 0 2 1 0 3 1 0 2 2 31 2 2 0 5 0 Abrupt 1 6 0 9 6 0 3 9 8 6 3 11 TABLE II.— BELATIVE QUALITIES of OAKS of UNIFORM SIZE, as shown by Table I.

No.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 I Order of Weight Quebec ditto, ditto Norway ditto ditto . . . .

Norway Batten, White. . . .

Norway Batten, White . . . .

Ditto, ditto Baltic Spar, ditto Baltic Batten ditto. . . .

Baltic Spar, ditto . . .

Baltic Batten Yellow . , Norway Batten, "White . . . .

Baltic ditto Yellow .

Baltic ditto White Norway Batten White Norway Spar White Quebec Batten, Yellow . . . .

Quebec Batten, Yellow . . . .

Baltic Batten White . .

Lbs.

14} 15i 15J 15J 151 16 16 16i 161 16f 17 17 17i l?i 17i 171 18 18 181 19 19 191 19f 20 20 20 20 20 20i 201 SOJ 211 231 24 Order of Deflection, at f-cwt. at blade = li cwt, at handle.

Baltic Spar, White „ , . „ . , Baltic ditto, ditto Quebec ditto Yellow Norway Batten, White . . . .

Norway Batten White . . . .

Baltic Batten, White . . . .

Norway Batten White . . .

Baltic Batten White . . . .

Baltic ditto ditto Baltic ditto, ditto Ditto ditto . . . .

Ditto ditto Norway Spar, White . . . .

Baltic Batten, Yellow Ditto ditto Quebec Spar, White Inches.

11 3i 3* 41 41 41 4i 44 5 5 51 51 51 6 6 6 6 6 6 61 61 61 6J 7 7 7 7 7 71 8 8 8 9 9 TABLE HE. — AVEBAGE QUALITIES of each Description of OABS TESTED.

No.

1 2 3 4 5 6 7 8 9 10 11 12 Order of Weight.

Baltic Batten Yellow Quebec Batten, Yellow . . . .

American Pitch Pine, Yellow. . .

Lbs.

15i 16i 171 l?i 17| 18 18i 191 19} 20 20 23| Order of Deflection at J-cwt.

Quebec Batten, Yellow . . . .

Baltic Spar White Baltic Batten ditto Norway Spar, White . . . .

Quebec Spar, White Baltic Batten, Yellow . . . .

Inches.

31 41 4i 4| 51 Sf * 61 7 n 7i 9 TABLE II. continued. — RELATIVE QUALITIES of OABS of UNIFOBM SIZE, as shown by Table I.

.No.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 23 29 30 31 32 33 34 Order of Strength.

Quebec Ash. • American Ash •• Larch . .

Ditto, ditto . . . . . .

Ditto, ditto . . .

Quebec Batten Yellow Ditto ditto Baltic Spar White .

Oregon Pine Timber .

Ditto, ditto . . . . .

Norway Spar "White .

Baltic ditto ditto .

Norway Batten ditto Baltic ditto ditto , . . .

Ditto, ditto .

Larch Batten . . . .

Ditto, ditto .

Baltic Spar, White . . . , .

Norway Batten ditto . .

Baltic ditto ditto .

Baltic ditto Yellow .

Ditto ditto American Pitch Pine • Baltic Batten Yellow . . . . .

Larch Batten .

Norway Spar White .

Quebec Spar White Ditto ditto Norway Batten Cwt. qrs. Ibs.

4 0 01 3 0 0 I 2 1 8 ] 3 2 21 3 0 0 2 3 21 ) 2 3 17 I 2 3 4 j 2 2 15 2 2 7 2 1 25 2 1 21 2 1 17 ) 2 1 16 j 2 1 11 2 1 0 2 1 0 2 0 20 2 0 0 2 0 0 1 3 26 1 3 24 1 3 23 1 3 22 1 3 14 1 3 14 1 3 7 1 3 7 1 3 0 1 2 0 1 1 27 1 1 19 1 1 M 11 0 Remarks, &c.

Unbroken at these weights, the great deflection having brought the weights to the ground.

Strain in direction of the grain of the wood.

Strain across the grain.

TABLE III. continued. — AVERAGE QUALITIES of each Description of OARS TESTED.

No.

1 2 3 4 5 6 7 8 9 10 11 12 Order of Strength.

Quebec Ash American Ash Oregon Pine . .

Quebec Batten, Yellow Baltic ditto White Norway Spar ditto 'Baltic ditto ditto Norway Batten, ditto . . . . .

Baltic ditto, Yellow Larch ditto American Pitch Pine Quebec Spar White Cwt qrs. Ibs.

3 3 10 3 0 0 2 2 21 2 2 11 2 0 15 2 0 6 2 0 3 1 3 12 1 3 10 1 3 9 1 3 7 1 1 19 Eetnarks, &c.