53 
THE CONCENTRATION OP FIRE FROM FORTS. 
BY 
LIEUTENANT G. TYACKE, R.A. 
In the present system of fighting a fort by Position-Finder, all the 
guns of a group are laid for direction on parallel lines by means of the 
arcs on the gun-floor. Consequently the front over which their fire is 
distributed at all ranges is equal to the distance between the flank 
guns, and supposing the objective to be a ship lying end-on to the 
battery, the fire of these flank guns might certainly be wasted, as 
might even be the case if she were lying broadside-on. 
To secure the advantages afforded by the dispersion of guns then, 
parallel fire must be given up and some plan for the concentration of 
fire adopted. 
It seems to me that this could be done more or less effectively in 
three ways :— 
1. At the Position-Finding instrument, which would then 
communicate to the training dials the corrected reading 
required to make the lines of fire of the group cross at the 
range for which the guns are laid. I cannot say if this be 
practicable or not. It would involve training dials for 
every gun. 
2. At the guns, by permanently fixing the training pointers 
of the flank guns of a group so that their lines of fire cross 
at.a point, say at 2500 yards range. 
3. At the guns, by having the training pointer capable of 
lateral movement on the gun-slide in connection with a 
deflection scale. 
It is for the Position-Finding specialist to say if 1 is practicable, 
but it must necessarily add to the complication of mechanism which is 
already intricate. 
The method set forth in 2 would only correct exactly for the particu¬ 
lar range for which the pointers were fixed. If a medium range be 
taken as the point at which the lines of fire shall cross, these lines at 
double that range will be no further apart than if the guns were laid 
parallel, and at all intermediate ranges they will be close together. 
See Figs, (a) and (6). 
2 , YOL, XIX. 
