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mto two, and I placed the twelve, each having fore and aft, and the sails trimmed according the same obliquity, in a line behind each other, as the wind is more or less against your course. when I perceived a great augmentation in its It seems to me that the management of a velocity, which encouraged me to divide them shallop so rigged would be very easy, the once more, and continuing the same obliquity, sails being run up and down separately, so I placed the twenty-four behind each other in that more or less sail may be made at pleaa line, when the force of the wind being the sure; and I imagine, that there being full as same, and the surface of vane the same, they much sail exposed to the force of the wind moved round with much greater rapidity, and which impels the vessel in its course, as if the perfectly answered my purpose.
whole were in one piece, and the resistance of The second experiment that I propose, is to the dead air against the foreside of the sail take two playing cards of the same dimen- being diminished, the advantage of swiftness sions, and cut one of them transversely into would be very considerable; besides that the eight equal pieces; then with a needle string vessel would lie nearer the wind. them upon two threads one near each end, Since we are on the subject of improveand place them so upon the threads that, when ments in navigation, permit me to detain you hung up, they may be one exactly over the a little longer with a small relative observaother, at a distance equal to their breadth, tion. Being, in one of my voyages, with ten each in a horizontal position; and let a small merchant-ships under convoy of a frigate at weight, such as a bird-shot, be hung under anchor in Torbay, waiting for a wind to go them, to make them fall in a straight line to the westward ; it came fair, but brought when let loose. Suspend also the whole card in with it a considerable swell. A signal was by threads from its four corners, and hang to given for weighing, and we put to sea altogeit an equal weight, so as to draw it down- ther; but three of the ships left their anchors, wards when let fall, its whole breadth press their cables parting just as their anchors came ing against the air. Let those two bodies be a-peak. Our cable held, and we got up our attached, one of them to one end of a thread anchor; but the shocks the ship felt before a yard long, the other to the other end. Ex- the anchor got loose from the ground, made tend a twine under the cieling of a room, and me reflect on what might possibly have causput through it at thirty inches distance two ed the breaking of the other cables ; and I pins bent in the form of fish-hooks. On these imagined it might be the short bending of the two hooks hang the two bodies, the thread cable just without the hause-hole, from a hothat connects them extending parallel to the rizontal to an almost verticle position, and the twine, which thread being cut, they must be sudden violent jerk it receives by the rising gin to fall at the same instant. If they take of the head of the ship on the swell of a wave equal time in falling to the floor, it is a proof while in that position. For example, suppose that the resistance of the air is in both cases a vessel hove up so as to have her head nearly equal. If the whole card requires a longer over her anchor, which still keeps its hold pertime, it shows that the sum of the resistances haps in a tough bottom; if it were calm, the cato the pieces of the cut card is not equal to ble still out would form nearly a perpendicuthe resistance of the whole one.*
lar line, measuring the distance between the This principle so far confirmed, I would hause-hole and the anchor; but if there is a proceed to make a larger experiment, with a swell, her head in the trough of the sea will fall shallop, which I would rig in this manner. below the level, and when lifted on the wave Same plate, Fig. 4.
will be much above it. In the first case the A B is a long boom, from which are hoisted cable will hang loose, and bend perhaps as in seven jibs, a, b, c, d, e, f, g, each a seventh figure 5. In the second case, figure 6, the part of the whole dimensions, and as much cable will be drawn straight with a jerk, must more as will fill the whole space when set in sustain the whole force of the rising ship, and an angle of forty-five degrees, so that they must either loosen the anchor, resist the rising may lap when going before the wind, and force of the ship, or break. But why does it hold more when going large. Thus rigged, break at the hause-hole ? when going right before the wind, the boom Let us suppose it a cable of three inches should be brought at right angles with the diameter, and represented by figure 7. If this keel, by means of the sheet ropes C D, and all cable is to be bent round the corner A, it is the sails hauled flat to the boom.
evident that either the part of the triangle These positions of boom and sails to be va- contained between the letters a, b, c, must ried as the wind quarters. But when the stretch considerably, and those most that are wind is on the beam, or when you would turn nearest the surface; or that the parts between to windward, the boom is to be hauled right d, e, f, must be compressed; or both, which
most probably happens. In this case the low
er half of the thickness affords no strength try this simple experiment at sea, when the proposal of against the jerk, it not being strained, the shore, and succeeded as the other.
upper half bears the whole, and the yarns
* The motion of the vessel made it inconvenient to
near the upper surface being first and most | may arrive at quantities of light wooden work, strained, break first, and the next yarns fol- empty chests, and particularly empty waterlow; for in this bent situation they cannot casks, which if fixed so as not to float thembear the strain altogether, and each contri- selves may help to sustain her. Many bodies butes its strength to the whole, as they do which compose a ship’s cargo may be speciwhen the cable is strained in a straight line. fically lighter than water, all these when out
To remedy this, methinks it would be well of water are an additional weight to that of to have a kind of large pulley wheel, fixed in the ship, and she is in proportion pressed the hause-hole, suppose of two feet diameter, deeper into the water ; but as soon as these over which the cable might pass; and being bodies are immersed, they weigh no longer on there bent gradually to the round of the wheel, the ship, but on the contrary, if fixed, they would thereby be more equally strained, and help to support her, in proportion as they are better able to bear the jerk, which may save specifically lighter than the water. And it the anchor, and by that means in the course should be remembered, that the largest body of the voyage to save the ship.
of a ship may be so balanced in the water, One maritime observation more shall finish that an ounce less or more of weight may this letter. I have been a reader of news. leave her at the surface or sink her to the papers now near seventy years, and I think bottom. There are also certain heavy carfew years pass without an account of some goes, that, when the water gets at them, are vessel met with at sea, with no living soul continually dissolving, and thereby lightning on board, and so many feet of water in her the vessel, such as salt and sugar. And as hold, which vessel has nevertheless been say- to water-casks mentioned above, since the ed and brought into port: and when not met quantity of them must be great in shi with at sea, such forsaken vessels have often war where the number of men consunr a come ashore on some coast. The crews, who great deal of water every day, if it had been have taken to their boats and thus abandoned made a constant rule to bung them up as fast such vessels, are sometimes met with and as they were emptied, and to dispose the taken up at sea by other ships, sometimes empty casks in proper situations, I am perreach a coast, and are sometimes never heard suaded that many ships which have been sunk of Those that give an account of quitting in engagements, or have gone down aftertheir vessels generally say, that she sprung a wards, might with the unhappy people have leak, that they pumped for some tim that been saved; as well as many of those which the water continued to rise upon them, and in the last war foundered, and were never that, despairing to save her, they had quitted heard of. While on this topic of sinking, one her lest they should go down with her. It cannot help recollecting the well known seems by the event that this fear was not al- practice of the Chinese, to divide the hold of ways well founded, and I have endeavoured a great ship into a number of separate chamto guess at the reason of the people's too hasty bers by partitions tight caulked (of which you discouragement.
gave a model in your boat upon the Seine) so When a vessel springs a leak near her bot- that if a leak should spring in one of them the tom, the water enters with all the force given others are not effected by it; and though that by the weight of the column of water, without, chamber should fill to a level with the sea, it which force is in proportion to the difference would not be sufficient to sink the vessel.of level between the water without and that we have not imitated this practice. Some within. It enters therefore with more force little disadvantage it might occasion in the at first and in greater quantity, than it can af- stowage is perhaps one reason, though that I terwards when the water within is higher.— think might be more than compensated by an The bottom of the vessel too is narrower, so abatement in the insurance that would be that the same quantity of water coming into reasonable, and by a higher price taken of that narrow part, rises faster than when the passengers, who would rather prefer going in space for it to flow is larger. This helps to such a vessel. But our sea-faring people terrify. But as the quantity entering is less are brave, despise danger, and reject such and less as the surfaces without and within be- precautions of safety, being cowards only come more nearly equal in height, the pumps in one sense, that of fearing to be thought that could not keep the water from rising at afraid. first, might afterwards be able to prevent its I promised to finish my letter with the last rising higher, and the people might have re-observation, but the garrulity of the old man mained on board in safety, without hazarding has got hold of me, and as I may never have themselves in an open boat on the wide ocean. another occasion of writing on this subject, I (Fig. 8.)
think I may as well now, once for all, empty Besides the greater equality in the height my nauticle budget, and give you all the of the two surfaces, there may sometimes be thoughts that have in my various long voyother causes that retard the farther sinking ages occurred to me relating to navigation. I of a leaky vessel. The rising water within am sure that in you they will meet a can
did judge, who will excuse my mistakes on sea almost as easily as a barrel. More bal. account of my good intention.
last by this means becomes necessary, and There are six accidents that may occasion that sinking a vessel deeper in the water octhe loss of ships at sea. We have considered casions more resistance to her going through it. one of them, that of foundering by a leak.- The Bermudian sloops still keep with advanThe other five are, 1. Oversetting by sudden tage to the old spreading form. The islandflaws of wind, or by carrying sail beyond the ers in the great Pacific ocean, though they bearing. 2. Fire by accident or carelessness. have no large ships, are the most expert boat3. A heavy stroke of lightning, making a sailors in the world, navigating that sea safebreach in the ship, or firing the powder. 4. ly with their proas, which they prevent overMeeting and shocking with other ships in the setting by various means. Their sailing proas night. 5. Meeting in the night with islands for this purpose have outriggers, generally of ice.
to windward, above the water, on which, one To that of oversetting, privateers in their or more men are placed, to move occasionally first cruize have, as far as has fallen within further from or nearer to the vessel as the my knowledge or information, been more sub- wind freshens or slackens. But sorne have ject than any other kind of vessels. The dou- their outriggers to leeward, which, resting ble desire of being able to overtake a weaker on the water, port the boat so as to keep flying enemy, or to escape when pursued by a her upright when pressed down by the wind. stronger, has induced the owners to overmast Their boats moved by oars or rather paddles, their cruizers, and to spread too much canvas; are for long voyages, fixed two together by and the great number of men, many of them cross bars of wood that keep them at some not seamen, who being upon deck when a distance from each other, and so render their ship heels suddenly are huddled down to lee- oversetting next to impossible. How far this ward, and increase by their weight the effect may be practicable in larger vessels, we of the wind. This therefore should be more have not yet sufficient experience. I know attended to and guarded against, especially as of but one trial made in Europe, which was the advantage of lofty masts is problematical. about one hundred years since, by Sir Wm. For the upper sails have greater power to Petty. He built a double vessel, to serve as lay a vessel more on her side, which is not the a packet boat between England and Ireland. most advantageous position for going swiftly Her model still exists in the museum of the through the water. And hence it is that ves- Royal Society, where I have seen it. By the sels, which have lost their lofty masts, and accounts we have of her, she answered well been able to make little more sail afterwards the purpose of her construction, making sethan permitted the ship to sail upon an even veral voyages; and though wrecked at last keel, have made so much way, even under by a storm, the misfortune did not appear owjury masts, as to surprise the mariners them- ing to her particular construction, since many selves. But there is besides, something in other vessels of the common form wrecked at the modern form of our ships that seems as if the same time. The advantage of such a calculated expressly to allow their overset- vessel is, that she needs no ballast, therefore ting more easily. The sides of a ship, in- swims either lighter or will carry more goods; stead of spreading out as they formerly did and that passengers are not so much incomin the upper works, are of late years turned moded by her rolling : to which may be added in, so as to make the body nearly round, and that if she is to defend herself by her cannon, more resembling a cask. I do not know what they will probably have more effect, being the advantages of this construction are, ex- kept more generally in a horizontal position, cept that such ships are not easily boarded. than those in common vessels. I think, howTo me it seems a contrivance to have less ever, that it would be an improvement of that room in a ship at nearly the same expense. model, to make the sides which are opposed For it is evident that the same timber and to each other perfectly parallel, though the plank consumed in raising the sides from a other sides are formed as in common, thus, to b, and from d to c, would have raised them figure 10. from a to e, and from d to f, fig. 9. In this The building of a double ship would indeed form all the spaces between e, a, b, and c, d, be more expensive in proportion to her burf, would have been gained, the deck would den; and that perhaps is sufficient to discouhave been larger, the men would have had rage the method. more room to act, and not have stood so thick The accident of fire is generally well in the way of the enemy's shot; and the ves- guarded against by the prudent captain's strict sel, the more she was laid down on her side, orders against smoking between decks, or the more bearing she would meet with, and carrying a candle there out of a lantern. more effectual to support her, as being farther But there is one dangerous practice which frefrom the centre. Whereas in the present quent terrible accidents have not yet been form, her ballast makes the chief part of her sufficient to abolish; that of carrying storebearing, without which she would turn in the spirits to sea in casks. Two large ships, the
VOL. II....3 A
Serapis and the Duke of Athol, one an East- der as savages have improved the art of sail. Indiaman, the other a frigate, have been burnt ing and rowing boats in several points beyond within these two last years, and many lives what we can pretend to. We have no sailingmiserably destroyed, by drawing spirits out of boats equal to the flying proas of the South a cask near a candle. It is high time to make Seas, no rowing or paddling-boat equal to that it a general rule, that all the ship's store of of the Greenlanders for swiftness and safety. spirits should be carried in bottles.
The birch canoes of the North-Americ InThe misfortune by a stroke of lightning dians have also some advantageous properties. I have in my former writings endeavoured to They are so light that two men may carry one show a method of guarding against
, by a chain of them over land, which is capable of carryand pointed rod, extending, when run up, ing a dozen upon the water; and in heeling from above the top of the mast to the sea. they are not so subject to take in water as These instruments are now made and sold at our boats, the sides of which are lowest in the a reasonable price by. Nairne & Co. in London, middle where it is most likely to enter, this and there are several instances of success at- being highest in that part, as in figure 11. tending the use of them. They are kept in The Chinese are an enlightened
people, the a box, and may be ran up and fixed in about most anciently civilized of any existing, and five minutes, on the apparent approach of a their arts are ancient, a presumption in their fathunder gust.
vour: their method of rowing their boats dif. Of the meeting and shocking with other fers from us, the oars being worked either two ships in the night I have known two instances a-stern as we scull, or on the sides with the in voyages between London and America. In same kind of motion, being hung parallel to one both ships arrived though much damaged, the keel on a rail, and always acting in the each reporting their belief that the other must water, not perpendicular to the side as ours have gone to the bottom. In the other, only are, nor lifted out at every stroke, which is a one got to port; the other was never after- loss of time, and the boat in the interval loses wards heard of. These instances happened motion. They see our manner, and we theirs, many years ago, when the commerce between but neither are disposed to learn of or copy the Europe and America was not a tenth part of other. what it is at present, ships of course thinner To the several means of moving boats menscattered, and the chance of meeting propor- tioned above, may be added the singular one tionably less. It has long been the practice lately exhibited at Javelle, on the Seine below to keep a look-out before in the channel, but Paris, where a clumsy boat was moved across at sea it has been neglected. If it is not at that river in three minutes by rowing, not in present thought worth while to take that pre- the water, but in the air, that is, by whirling caution, it will in time become of more con- round a set of windmill vanes fixed to a horisequence; since the number of ships at sea is zontal axis, parallel to the keel, and placed continually augmenting. A drum frequently at the head of the boat. The axis was bent beat, or å bell rung in a dark night, might into an elbow at the end, by the help of which help to prevent such accidents.
it was turned by one man at a time. I saw Islands of ice are frequently seen off the the operation at a distance. The four vanes banks of Newfoundland, by ships going be- appeared to be about five feet long, and pertween North America and Europe. In the haps two and a half wide. The weather day time they are easily avoided, unless in a was calm. The labour appeared to be great very thick fog. I remember two instances of for one man, as the two several times relievships running against them in the night. The ed each other. But the action upon the air first lost her bowspirit
, but received little by the oblique surfaces of the vanes must other damage. The other struck where the have been considerable, as the motion of the warmth of the sea had wasted the ice next to boat appeared tolerably quick going and reit, and a part hung over above. This perhaps turning; and she returned to the same place saved her, for she was under great way; but from whence she first set out, notwithstandthe upper part of the cliff taking her fore- ing the current. This machine is since aptopmast, broke the shock, though it carried plied to the moving of air-balloons: an inaway the mast. She disengaged herself with strument similar may be contrived to move a some difficulty, and got safe into port; but the boat by turning under water. accident shows the possibility of other ships Several mechanical projectors have at dif being wrecked and sunk by striking those vast ferent times proposed to give motion to boats, masses of ice, of which I have seen one that and even to ships, by means of circular rowwe judged to be seventy feet high above the ing, or paddles placed on the circumference water, consequently eight times as much un- of wheels to be turned constantly on each side der water; and it is another reason for keep of the vessel; but this method, though freing a good look-out before, though far from quently tried, has never been found so effecany coast that may threaten danger. tual as to encourage a continuance of the
It is remarkable, that the people we consi- | practice. I do not know that the reason has