XXI. Hints respecting Naval Archil eclure. By A Cohre- 



SrONDENT. 



To Mr. Tilloch. 



Y Chatham, March 1, 1820. 



Sir, — It would doubtless be a waste of time to say any thing 

 on the importance to this country, of naval force ; consequently 

 every attempt (however limited) for the improvement of ships of 

 war, whether in their construction or oeconomy, should at least 

 receive a candid examination. 



It is well known that all line-of-battle ships, I mean those of 

 74 guns, carry a large quantity of iron as ballast — small class 160, 

 large class 185 tons. Now, could not the greater portion of that 

 material be so disposed of as to add to the strength as well as sta- 

 bility of the ship ? For example : instead of the usual method of 

 supporting the beams in the middle by perpendicular pieces of 

 timber from the keelson to the orlop-deck beams, would it not 

 be much "better to make use of cast-iron ? I mean the present 

 ballast re-caSt into the requisite forms. The principal pieces 

 should be of a parabolic shape, when seen in the longitudinal 

 section of the ship, with the terminations somewhat enlarged and 

 circular ; at each end there should be a round hole, through 

 which a strong pin might pass, for the purpose of connecting 

 their adjoining ends ; the same pin should also pass through holes 

 in a plate having projections on it for that purpose, placed at a 

 proper distance to receive the ends of the parabolic pieces ; those 

 plates to be let into, and strongly bolted to, the keelson, and to 

 a strong fo»e and aft piece under the orlop deck beams ; to the 

 ends of this piece the stem and stern post should be securely 

 united, the parabolic pieces to be placed at the angle of 45°, in- 

 tersecting each other two or three times. If judged necessary, 

 the whole might form a reticular frame of the length and 

 depth of the hold, equally calculated to resist tension or com- 

 pression. The lower deck beams, that they may be capable of 

 resistance in opposite directions, should ])eofthe form proposed 

 for the oblique pieces, if of metal : should timber be preferred, 

 the shape should be the same, as near as is compatible with 

 the nature of that material. Of whatever material they are made, 

 they should, if possible, be sufficiently strong to support the su- 

 perincumbent weight of the ship, &c. I mean without encroach- 

 ing on the stowage. As it is intended that the longitudinal frame 

 should be continued without interruption from steuj to stern, the 

 hatchways must be increased in width. The masts may be made 

 either to step on, or double at their lower ends so as to pass 

 down by the sides of the frame. I cannot suppose that any ob- 

 jection can be made to using metal in the above manner in a 



Vol. 55. No. 263. March 1820. L ship's 



