454 ARCHITECHNICS. 



sails, extending from the top of any mast, to the foot of the one next 

 before it. The square sails, like the yards which support them, are 

 named from the contiguous masts ; and studding sails are sometimes 

 added on each side, to enlarge them, when the wind is light. 



The masts are held more steady by the shrouds ; which are strong 

 ropes extending from their tops down to the sides of the ship ; 

 and which, with cross ropes called rattlings, form ladders for the 

 sailors to ascend. The masts are prevented from falling backward, 

 by stays, or ropes extending from their tops downward and forward ; 

 and their back-stays have the reverse effect. The ropes for support- 

 ing the bowsprit and jib-boom, are called bobstays, martingales, and 

 guys. Those for managing the sails, are halyards, for raising them ; 

 sheets, for turning them to the wind ; with tacks, braces, lifts, and 

 clewlines ; all of which are called running rigging, to distinguish 

 them from the standing rigging, which remains fixed. 



Vessels are differently named, according to the manner of their 

 rigging. A sloop, has but one mast ; with gib, and mainsail, and 

 sometimes a square topsail. A schooner, has two masts, but with 

 fore-and-aft sails, except the topsails. A brig, has two masts, both 

 carrying square sails ; and a brigantine has two masts, but the 

 hinder, or mainmast, is rigged like that of a schooner. A ship, has 

 three masts, all square rigged : a barque has three masts, but the mizen 

 mast not square rigged ; and a three masted schooner, has three 

 masts, all fore and aft rigged. A ship of 500 tons burthen should be 

 about 100 feet long, and 30 broad ; drawing about 12 feet of water. 



3. The construction of Steamboats, is similar to that of sailing 

 vessels, except in the arrangements for applying the moving force. 

 Steamboats require to be built very strong, on account of the strain 

 and jarring of the machinery ; but the general arrangement of the 

 framing is the same as that which we have already described. For 

 river navigation, and transportation of passengers, the deck is made 

 much wider than the body of the vessel, by an extension of the deck 

 timbers ; an arrangement which, for ocean navigation, would be un- 

 safe. The proper adjustment of the engine or engines, to the boat, 

 as regards weight, shape, position, and power, is of course a subject 

 of the highest importance. A steamboat of 300 tons burthen, suited 

 for river navigation, should be about 120 feet long, and 30 feet broad; 

 with about 6 feet draught of water ; and should have an engine of 

 about 55 horse power, weighing about 32 tons ; with a cylinder of 

 3 feet diameter, a piston of 4 feet stroke, and paddle wheels 17 feet 

 in diameter, and 5 feet long. The fly wheel, is entirely superfluous 

 in steamboats, if they have two cylinders, with pistons acting on 

 cranks, at right angles to each other, on the axle of the paddle wheels. 

 For sea vessels, the engine is placed in the hold ; and the paddles 

 may be so constructed as to be unshipped, or taken in, during a gale. 



The causes of explosion of steam boilers, are various ; but chiefly, 

 the excessive heating of the boiler, while the engine is stopped, and 

 the sudden flow of water upon the heated part, producing the sudden 

 generation of a great quantity of steam ; the boiler at such times, 

 being already overcharged, unless the steam has been escaping freely 

 in the mean while. The best of all remedies, would be the thorough 



