333. The best effect of a percussion-fuze is obtained by firing into a mass of timber. They frequently fail if fired into a bank of soft earth, sand, or other material which does not offer a sufficiently sudden resistance; also, if fired at high angles of elevation, owing to the fact that the rifle-shells do not generally strike point foremost.
334. Time-fuzes are also very unreliable in rifle-guns; expanding projectiles cut off the flame from the fuze.
With the Parrott shell, however, the Navy time-fuze is the most certain of ignition and regular in its time of burning. The safety-plug should be removed when the Navy time-fuse is used in rifled cannon, as recent experiments show that it is a probable cause of premature explosions of shells.
In testing the Navy time-fuse by the watch, or michronometer, the safety-plug must be removed: otherwise the fuze will burn longer than the time for which it is marked.
BOARDERS.
335. It is not supposed that any directions can be framed which will entirely provide for all the various circumstances which may require attention when about to board an enemy, or to repel a similar assault made by an enemy upon our vessels.
The following general suggestions are, however, presented for the consideration of Captains, in order that some degree of uniformity may be preserved when other more important considerations do not prevent it.
336. Upon the signal for Boarders, the divisions called should form on the gangway of the side which is not engaged, properly armed, and remain there until ordered elsewhere, provided there be time to make this disposition of them. In all movements from one part of the ship to another, cutlasses should be sheathed and pistols in the frogs. The men of each division should be united as much as possible under their own officer. Bayonets not fixed until ordered.
"PREPARE TO BOARD!"
(FROM ANY SPECIFIED PART OF THE SHIP.)