BARROJif, ON THE DRY ROT. 151 



prove, that more timber is employed in the construction of our 

 pubhc ships than is necessary for the purposes of strength alone ; 

 and regard to the valuable quality of buoyancy, should furnish a 

 strong reason for not lumbering them with superfluous materials. 

 It is an incontrovertible fact, that the merchant ships Iwve encoun- 

 tered the heaviest gales while in the condition above stated, without 

 exhibiting the slightest sign of weakness. Public ships, when so 

 loaded with timber, float too deep in the water, either for comfort 

 Or fast sailing. The practice too of ceiling the decks over head, 

 ibr ornament sake, is also ruinous to the beams and deck-plank it- 

 self, while it so much increases the weight in timber, of which I 

 complain. 



" All national vessels should be built with copper bolts, wherever 

 they can be introduced, to be secured by screw taps on their inner 

 ends, and removed or replaced at pleasure when a ship is repaired ; 

 and by no means should the present practice of cutting out plank 

 and breaking off bolts be allowed ; being a great waste of time, 

 and often of valuable materials. If ships were built in the manner 

 here recommended, the strakes of plank might be removed or re- 

 placed with convenience, without an additional hole being bored 

 in the frame. It might probably become necessary, in this case, to 

 use bolts one size larger in repairing, as driving out (he bolts might 

 somewhat enlarge the hole. I should recommend one bolt in each 

 edge of the plank to pass through each timber composing the frame, 



thus. 



and not to use tree-nails or 



spikes at all, in any part of a ship where they can be dispensed 

 with. Thus constructed, ships can be completely ventilated, and 

 when they require repairs, they may be taken asunder with perfect 

 ease, and in a manner to expose every part of their frame to view, 

 by which plan no defect can be concealed or rendered diflicult to 

 remove. 



" Again, ships should be built in regular frames, coaged or dowel- 

 led together, and strongly bolted from the floors to the top timbers. 

 These frames should be placed from eiglit to twelve inches apart, 

 (according to the size of the ship ;) the ceiling, as far up from the 

 keelson, as one or two strakes above the floor heads, may be flush, 

 and then chamfered pieces, (a term used by carpenters for horizon- 

 tal pieces of plank,) perforated with many small, smooth holes, let 

 in between the timber — covering the openings between the ceiling' 

 and outside plank, to admit the ficsh air, as fast as the foul is pump- 

 ed out by ventilators : the ceiling should then be partial up to the 

 strake below the clamps of the lower guu-deck ; using only three 

 strakes of ceiling of from eight to twelve inches wide (according to 

 the size of the ship) over each joining of the timbers. The ceiling 

 should be of plank one-thiid thicker than that commonly used, an(i 

 the fiame let into it fully that (bird, (heieby forming a kind uf jog 

 and chock work, on the principle of a stjuare, supported from the 



point of each angle, thus, ^^-^^ which i-enders the wltoic frame 



