The blocks being relieved of the vessel in the usual manner, the keel beam, with the after cross beam will run from under her. The carriage is again put to gether, and another vessel can be hauled up astern of the former. In point of fact, it is usual to have more than one vessel on the slip at the same time.
In launching a vessel, the cross pieces with their blocks arc placed beneath her, and she immediately descends into the water. In order to launch and haul up vessels the same tide, temporary blocks arc put under the bottom of the vessel to be launched, upon the cross pieces, instead of the sliding blocks which arc prepared as before to suit the bottom of the ves sel to be taken up. The vessel is then launched, and she and the temporary blocks which steadied her, float from the carriage. The other vessel is then taken on and hauled up as formerly described.
The advantages of this invention arc numerous and important. It can be erected in situations where it is impracticable to have a dry clock, and at an expense which is comparatively inconsiderable; and it can be removed from one place to another, and may even be carried on board a ship, and applied to use on voyages of discovery and in remote situations, where repairs would otherwise be impracticable. The ap paratus and the ship under repair being both above ground, the air has a free circulation; the men work with more comfort, and in winter they have the light much longer than within the walls of a dry dock. There is a saving of time in carrying the materials for repairing the ship; and such is the facility of the whole operation, that ships can be hauled up and in spected, and even get a trifling repair, and be launch ed again the same tide. As the mechanical power is attached solely to the carriage, the vessel is exposed to no strain, and the work of repair on one vessel is never interrupted by hauling on another, as in dry docks.
The whole expense of Mr. Morton's slip, exclusive of the cost of preparing the foundation and laying down, (which must vary according to circumstances) may be stated nearly as follows, viz.
and for vessels of greater burden in proportion.
An attempt was made about four years ago to in vade Mr. Morton's patent; hut his right was finally established by a court of law. On this occasion a number of witnesses were examined, including seve ral officers of -high rank in the royal navy, who all agreed that the slip was an invention of great prac tical utility; the naval officers being farther of opinion, that it might be made to answer for hauling ships of war out of water as well as mercantile vessels. The
editor of this work has also seen the most satisfactory statements from a number of shipbuilders and others who have used the slip for several years, during which not a single accident has occurred in their practice, any more than in that of the patentee himself. It is now in use in many of the seaports of Great Britain and Ireland; slips have also been sent by Mr. Morton to France and Russia by the orders of the governments of these countries; and one, we understand, has been recently forwarded to Philadelphia.
With reference to the introduction of the slip into the United States of America, it may be mentioned, that within these three years an apparatus, meant to serve the same purpose, has been erected at New York by a native of Great Britain, all the valuable parts of which seem to have been taken from Mr. Morton's slip, with the addition of other contrivances of little or no utility, to give it the appearance of an original invention. The expense of this construction must have been several times that of Mr. Morton's. The apparatus laid down at Manhattan Island, under stood to be for vessels of 400 or 500 tons, having cost, (but every thing included till it was ready for use,) nearly R17,000; and it does not appear to be calculated to receive more than one vessel at a time. We have looked into the documents containing these facts, and think it due to our country and our coun trymen, that our transatlantic brethren should not be allowed the merit invention to which they have no just claim.
Such we conceive to be its importance to the mer cantile interest, that we think it may be useful to men tion some of the ports in different parts of the United Kingdom, where it may be seen in use, viz.
Aberdeen lIarwich • Shields Arbroath Ipswich Shoreham llerwick Irvine Sunderland Borrowstownness Leith Swansea Dublin Liverpool Waterford Dumbarton Maryport Whitchaven Dysart Newcastle Workington Edinburgh (Union Canal)