34 Naval Architecture and 



axis. Thus, the upper planks afford more strength than 

 those at the water's edge, which cannot come into action 

 till those above or below are considerably stretched or 

 compressed. For this reason Dr. Young observes- — *' The 

 least obvious advantage attributable to the obliquity intro- 

 duced by Mr. Seppings, appears to be in his mode of laying 

 the planks of the decks ; parts which seem to be principally 

 required to co-operate with the sides of the ship as ties in a 

 longitudinal direction." 



The fillings between the timbers certainly cannot afford 

 any strength to the ship ; their resistance to compression is 

 not equal to that of a coat of planking, which acts in the 

 direction of its fibres, with numerous fastenings, both to 

 prevent compression and extension — the latter of which the 

 fillings can have no sort of pretension to. As the ship is 

 not tilled up to the floatation, water is not excluded by 

 them in all cases from entering the ship. Their introduc- 

 tion only became necessary when the ceiling was dispensed 

 with; and thus forming a part of the new system, they 

 must stand or fall with it. It has been adduced in favour 

 of filling in a ship, that the weight being below the centre 

 of gravity, it must act as ballast : to this fallacious recom- 

 mendation it need only be observed, that one ton of bal- 

 last, placed at the bottom of the hold, would have the effect 

 of two or three tons placed in the situation of the fillings. 



It must also be recollected, that an objection has arisen 

 to the interior planking on account of its weight, while the 

 same has not been alleged of the fillings ; but Dupin, who 

 notices this, sometimes writes with mere political views, 

 without a scrupulous regard to correctness ; for the truth 

 of which assertion we need only adduce his account of the 

 British treatment of French prisoners, and his omission of 

 taking the weight of the new fastenings of the beams into 

 consideration, so properly descanted on by Dr. Young, 

 which was mentioned before. 



We cannot conceive with what propriety, persons can 

 say that a coat of planking contributes little to the strength 

 of a ship, when it is merely the four-inch planks of the 

 bottom of a ship that bind together and protect three or 

 four thousand tons of heterogeneous matter from all the 

 ravages of the winds and waves. Perhaps, there is no pa- 

 rallel to this prodigious combination of strength, with dis- 

 proportionably small substances, in the whole range of the 

 arts : the arch and the hoop, where the separating forces 

 are equally distributed and counteracted by the continuity 



