1835.] FRENCH AND ENGLISH NAVAL OFFICERS. order in the state; thus losing on one hand what they may gain on the other. Could the present unusual charges of the Royal Naval College be made to reach the means of the Navy, and of which there can be little doubt, and a system of gymnastics, which to the sailor is almost equally essential with navigation, be established as at Greenwich, which has sent forth youngsters calculated in every way for most able and skilful seamen, and a vessel be also a part of the institution, to unite practice with theory, by cruising occasionally in the Channel, then those objections so frequently raised against the Royal Naval College would be removed, as its internal management leaves nothing at which the most captious could cavil. If the pay and comforts of the English officer sink thus beneath those of the French, their widows occasionally suffer in a still greater ratio; for while France places at the disposal of the Minister 30,000 francs annually for the purchase of chronometers and mathematical instruments, &c.-in our country, such is the little sympathy voluntarily manifested by government for nautical science or improvement, that the widow of Captain Skyring, who was sent on a survey to the coast of Africa, in the execution of which he fell, like his great countryman Cook, a victim to his zeal and perseverance, disfigured by seventy wounds from the African lance, was compelled to enlist the charity of a British public to meet the demands of her husband's creditors, who had furnished him with scientific instruments to prosecute that survey, in which the public alone were interested. Thus we have carefully and impartially collated the benefits and disadvantages of either service; and if reason and justice be the standard which must guide us to the conclusion, every lover of the one and allowadmirer of the other must at once pronounce an opinion, that the French and English Navy are, with respect to liberal treatment, pay, ances, consideration, advance by service or merit in every grade, both as regards themselves, their wives and children, and in all things directly and indirectly, in diametrics to each other; and that the advantages on the part of the French officer predominate so manifestly over those of the English, that it is not only the more surprising, because this arm is less esteemed in France, but also the more painful because the English officer less demerits this treatment: that although since the peace reforms have been demanded and instituted in all branches of the legislature by the unanimous and repeated petitions. of the national bodies, yet in the Navy, who have for years past, up to the present hour, exposed glaring abuses, corrupt influence, and every other species of grievances and acts which disrepute and destroy its character, yet not one remedy has been applied, except for financial purposes; and so far from reform having arrested those evils, which time and irresponsible power necessarily introduce into all public institutions, the Navy has daily become less efficient, less esteemed, and less noticed than any public body in the country. August 14th, 1835. W. H. DICKSON. CALCULATIONS RECENTLY MADE ON TWENTY SHIPS OF THE BRITISH NAVY, WITH OBSERVATIONS RESPECTING THE FORMS OF SOME OF THOSE SHIPS. BY MR. WILLIAM HENWOOD, NAVAL ARCHITECT. THE following calculations have been made by the writer, with the view of ascertaining how far the forms of the several classes of ships of the royal navy differ from that form which ships of similar size would have, if they were to be constructed according to the principles advanced in pages 365 and 366 in the United Service Journal' for November, 1833, in the "Inquiry respecting the means of reducing the motions of pitching and scending to a minimum." It will be proper just to state, that the principles referred to rest on the following considerations,-namely, that when a ship is sailing the pitching and scending motions always diminish the velocity of the vessel; and in a degree corresponding with the greater or less degree of force with which those motions are performed. The motion of rolling can have very little effect in retarding the velocity of sailing, compared with the effect produced by the pitching. And it is accordingly obvious that if a ship can be so constructed and equipped that the force of the pitching and scending motions shall be made the least possible, the sailing of the ship will be impeded by these motions in the least possible degree; whilst, at the same time, the ship being rendered perfectly easy in her longitudinal motions when under sail, her hull, masts, and rigging would be subjected to only the least possible degree of straining. It will appear evident to every attentive reader of the paper above referred to, that a ship may be so constructed and equipped. The forces with which a ship will pitch and scend depend, as was explained, in pages 365 and 366, No. 60, of this work, on the products of the displaced volumes of the fore and after bodies, and the squares of the distances of the centres of gravity of these bodies, respectively from the common centre of gravity of the ship; and on the products of the weights before and abaft the centre of gravity of the ship, and the squares of the distances of the common centres of gravity of those weights, respectively, from the same centre of gravity, or axis, of the ship. As, however, the moments of the weights on each side of the axis are equal to each other, and the moments of the fore and after bodies likewise equal, it is sufficient, in comparing the force of pitching with the force of scending, to compare merely the distances of the centres of gravity from the axis in each case. The accompanying table of calculations shows the force which the buoyancy of the water exerts on the fore and after bodies of the several ships, in producing their motions of pitching and scending. The tendency to pitch is represented by the distance of the centre of gravity of the after body from that of the ship; and the tendency to scend is in like manner expressed by the distance of the centre of gravity of the fore body from the same point. In the Caledonia, for example, the effect of the action of the water on the after body in making the ship pitch is expressed by 41, and the counteracting effect causing her to scend by 41. According to the principle I have endeavoured to establish in the above-mentioned paper, these effects of the buoyant force of the water on the fore and after bodies ought always, as they might be, made precisely equal to each other; whilst, at the same time, the weights which compose the ship on each side of the vertical plane passing through the transverse axis, should not only be equal, but disposed of in such a manner that the common centres of gravity of those weights may be equally distant from the centre of gravity, or transverse axis, of the ship. Caledonia, 120 guns. Rodney, 92 guns. Royal Frederick, 110 guns. Vengeance, 84 guns. Vengeance*, 84 guns. ft. ins. ft. ins. ft. ins. ft. ins. ft. ins. ft. ins. ft. ins. ft.' ins. ft. ins. ft. ins. ft. ins. ft. ins. ft. ins. 194 114 176 3 1727 172 10 159 4160 0152 9 120 0 126 0 ft. ins. ft. ins. ft. 40 14 34 0 111 2 ins. ft. ins. ft. ins. ft. ins. ft. ins. ft. ins. ft. ins. ft. ins. ft. ins. 20 1 19 5 17 6 16 7 21 2 21 8 195 186 167 21234 1531 1862 1428 770 873 943 563 606 feet • The calculations in the columns thus marked have been made at the sea-going draught of water, the others at the load water-line prescribed by their constructors. Vindictive, 74 guns. Winchester, 52 guns. President, 52 guns. Seringapatam, 46 guns. Inconstant, 36 guns. Minerva, 46 guns. Sapphire, 28 guns. Imogene, 28 guns. Challenger, 28 guns. Rover, 18 guns. Orestes, 18 guns. Champion, 18 guns. Columbine, 18 guns. Scylla, 18 guns. Waterwitch, 10 guns. Britomart, 10 guns. The Caledonia has been considered by many distinguished naval officers as a ship possessing good if not superior sailing qualities. And in making a comparison between this well-known ship and the ships of three decks in the foregoing table, it will be seen that the form of her bottom is such that her tendency to pitch is more nearly equal to her tendency to scend, than the same elements of either the Rodney or the Royal Frederick. If the latter ships should be stowed, with reference to the position of their centres of gravity of displacement, in the same manner as the Caledonia has been, they will most certainly pitch with greater force than that ship, and the Royal Frederick will be the most laboursome ship of the three. The situations of the centres of gravity of these ships, with respect to the middle point of the load water line, are so far different, that it must be supposed that all of them are not equally good. It appears exceedingly desirable that a naval architect, before beginning to construct a vessel of such magnitude and value, should be able to ascertain the best position for placing this highly important point,-through which the axes of rotation pass, and upon which the excellence of a ship essentially depends. If the axis of rotation is too far aft, it is plain that the ship will pitch too heavily; and if the axis is placed too far forward, the scending will be excessive; and in either case the sailing must be retarded. It evidently appears there is a mean position where the centre of gravity of a ship ought to be placed in order that her sailing may be impeded by the impact of the ship and the water in pitching, in the least possible degree; and this desirable point can be determined without any considerable difficulty. The difference in the situations of the centres of gravity of these ships will, in a slight degree, modify the numbers which have been found as expressions of the forces of pitching and scending. The centre of gravity in the Royal Frederick being about four inches farther forward than in the Caledonia, will, provided both ships are stowed in the way above supposed, diminish, in a small degree, the comparatively great difference of the tendencies to pitch and scend in the Royal Frederick. And the position of the centre of gravity in the Rodney will modify the numbers which represent the forces of the water acting on her in a similar manner. In adverting to the two calculations made on the Vengeance, it is deserving of notice that this ship exhibits in a striking point of view how desirable it is that the construction of our ships of war should be conducted on other principles than those which have served as the guide of naval architects. This ship was constructed to sail only eighteen inches by the stern, and her decks were placed with their fore and after ends about fifteen or sixteen inches higher than the midship part. The necessity of bringing this ship not less than fifteen inches more by the stern than her constructor designed her to be, in order to make her sail well, makes the lowest part of her decks to be very near the stern, instead of in midships, so that the water on her decks must run aft against her cabins, and less readily find a passage out of the ship. But this is not all. The appearance of the ship as she floats on the water is altogether spoiled, and an impression is made on the mind of every reflecting beholder that her constructor could not have known the way to make such a ship as he desired. A very erroneous notion has been entertained by some persons, that it is the part of those who have to navigate a ship to find out her trim, or best sailing draught of water. And this opinion appears to have been held quite as tenaciously by naval constructors as by other persons. Nothing but a very imperfect acquaintance with the science of naval architecture could have admitted the formation of such an opinion. A very little reflection will suffice to satisfy every well-informed individual that the naval architect, who merely delineates the form of the hull of a ship, and allows the weights to be stowed in her according to the discretion or caprice of another person, fulfils but half the duty of his office. He leaves the completion of his work, which is all but the most important part of it, to be executed by those who, it must be presumed, are uninformed of the proper mode of doing it; and it would be but fair to consider a ship, built and equipped in this manner, as the joint production of her architect and those who equip her for seaservice. If the constructor of the draught, from which the Vengeance was built, had been required to arrange all the weights on board his ship, preparatory to her going to sea, he would, it is to be supposed, in conformity with his design, have brought her to swim only eighteen inches by the stern. The ship, when at sea, would in all probability, or rather of necessity, have been found to plunge violently and deep in the act of pitching; and it would have been found expedient to break up the hold and re-stow the ship, in order to prevent her from carrying away her mast and rigging. This class of ships appears to have been found, by various officers who have had the command of them, to sail best at the draught of water in the second calculation, or even somewhat more by the stern. At this draught of water the tendency to pitch, arising from the effect of the fluid on the bottom, is much more nearly equal to the tendency to scend, than when the ship is only eighteen inches by the stern. And as the altered stowage, by which the difference in the draughts of water forward and aft was increased from one foot six inches to two feet nine inches, must also have rendered the force of pitching much more nearly equal to the force of scending, it is to be concluded that the principle of " an equal tendency to pitch and scend" is supported by the fact of this ship having been improved in her sailing by the above-mentioned alteration in her trim. By comparing the calculations of the Winchester and President, we see a most extraordinary difference in the distances of their centres of gravity of displacement from the middle of the load water line. Both positions for this important point, or axis of the ship, cannot be the best. It is probable that neither of them is the most eligible. The form of the Winchester makes her tendencies to pitch and scend much more nearly equal than the form of the President; whilst it is more than probable that the stowage of the latter frigate would counteract the tendency of the form of her bottom to increase her motion of pitching much more than the stowage of the former. And if the stowage has this effect, the pitching motion of the Winchester must exceed that of the President. The conclusion to be derived from these observations is, that it is very desirable that, before constructing ships of similar size in future, the best place for the centre of gravity of displacement should be found. In making a comparison between the two classes of 46 gun frigates and the Inconstant of 36 guns, now building from the design of Commodore Hayes, it will be observed, that the positions of the centres of gravity of displacement in the Seringapatam class and the Inconstant, are very nearly the same; and in both these vessels the tendencies to pitch and scend are much more nearly alike than in the Minerva class of frigates. If the centre of gravity of the Inconstant is not too far before the middle of her length, and probably it is not, it may be expected she will be rather more easy in her longitudinal motions at sea, than ships similar to the Seringapatam, and much more so than those like the Minerva. If any one, who has the means, will make a similar series of calculations of the Pique, the new frigate of 36 guns which a short time since arrived at Portsmouth from an experimental cruise with the Castor, it will most probably be found that the reason why it was necessary to bring the Pique, during her trial with the Castor, to so much greater a draught of water by the stern than that at which she was intended to sail is, either that her centre of gravity is much too far before the middle point of her length, or that her tendencies to pitch and scend are very unequal. The Imogene, of 28 guns, is believed to be nearly a fac-simile of the Tyne, the ship which, with the Sapphire and Challenger, formed part of the experimental squadron of 1829. The most remarkable feature in these vessels is that of the number of tons of the displacement. If the Sapphire, |