42 NAVAL SCIENCE8. 



jig. 3). After the vessel is caulked, the remaining pitch is scraped off. When 

 subsequently the caulking is repeated on the water, it is burnt off (/?/. S,fig. 4). 

 The planks are fastened with strong nails, and also with screw-bolts. The 

 cross seams are made to come on good timbers, and the different courses 

 must be jointed at least five feet apart. In ships of war, the cross seams must 

 not come over or under the port-holes. The thickness of the outside planks 

 varies. The bark-planks, which go round the body of the vessel like a belt 

 and form a projection, are twice as thick as the others. Large ships of war 

 have several courses of these planks. The planks on the bow and under the 

 chain-plates are as strong also, the rest are weaker. In large ships, the 

 outside planks are four and a half inches thick, and in small vessels never 

 under two inches. The planks on the bow are warped by fire. The sides 

 of the ship are also covered with planks inside. Sometimes a course is here 

 and there left open, in order to give the air access to the timbers. In ships 

 of war, the French have found an advantage in filling the space between the 

 planks with cotton, in order to weaken the force of cannon balls. 



The planking being finished, the next step is to construct- the decks. 

 The larger class of ships have several decks. In ships of war only those 

 which carry guns receive that name. The rest have different names, for 

 example, forecastle, orlop, quarter-deck, and so forth. The decks are com- 

 posed of timbers lying crosswise, and planks placed over them lengthwise. 

 The beam ends rest on a frame of strong timbers which run from the 

 stem to the transoms, close to the ribs. At the head they are joined to the 

 side-timbers with wooden or iron knees. In the centre, the beams are 

 supported by upright posts. Their distance from each other depends on 

 the position of the masts and hatchways. Half-beams are added when they 

 stand too far apart. The largest beam lies amidships, and is called the 

 sail-beam or the main-beam. The beams of the lower deck are shorter 

 than those of the upper, as men-of-war have the heaviest cannon on the 

 lower deck, and in general all the heavy parts must be placed as low as 

 possible. The decks are slightly raised in the centre, so that the water 

 may run off at the sides, passing through the scuppers, which are small holes 

 lined with lead. The decks also sink a little fore and aft towards the 

 scuppers which are at each end. 



3. Finishing of the Construction. After the carpenters have completed 

 the decks, they proceed to construct the hatchways, the ladders, the mast 

 steps, the chain-wales, the pumps, the capstan, the railings, and the hawser- 

 holes, and if the vessel is a man-of-war, the port-holes. The hatchways 

 are square openings, like trap-doors, leading from one deck to another. 

 Ships of war have five or six hatchways ; merchantmen usually have three, 

 the main hatchway and the fore and aft hatchways. The main hatchway 

 lies forward of the main-mast, the fore hatchway aft of the fore-mast, and 

 the aft hatchway abaft of the main-mast. There is also an opening at the 

 mizen-mast, but this is called the door, and the sky-light of the cabin. In 

 order to prevent the water from running through the hatchways into the 

 ship, they are surrounded by a frame six inches high (the coamings), and 

 covered with caps and tarred sailcloth, tarpaulin; when they are open a 

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