A CALCULATION OF PROBABILITY OF FIRE. 65 
1568 = 15°68 per cent., which would give the probable percentage of 
effective hits. 
Except with Position Finders it is difficult to obtain the exact value 
of @ or the angle of approach, but it is easy to draw up beforehand 
tables giving the probable percentage of hits for objectives at various 
speeds moving either directly towards or away (6=0), directly across 
¢=90°, or midway between the two 6=45°. For this it is necessary 
to have tables of F. C.’s corrections and a speed table in order to be able 
to select the proper value for WM. 
With electric range dials and when firing by Case II. the Fort time 
may be taken as 2”. 
The Fire Commander’s correction table will then be 
TABLE XV. 
F. C.’s corr". 
for 
Range 1000 2000 3000 4000 5000 6000 yds. 
tw ww Ww wt i mw 
10) 16 20 28 40 52 64. 
Be 8 mo le ay 0 a time to traverse 
50. 4 5 7 10 13 16 50 vd 2 ; 
75 3 4 5 fi 10 12 phe 
100 2 3 4 5 7 8 
TABLE XVI. 
for 1000 2000 3000 4000 5000 6000 yds. 
Training wt nt J m” , wt t wm 
9 16 24. 40 iL ak 1 28 2 16 
15! 8 12 20 32 44 i 
30’ 4 6 10 16 22, 34 
45! 3 5 74 12 17 26| time to 
ie 2 3 5 8 11 17\. traverse 
1 6y 13 28 44 7 10 16| JL ofare 
1° 30’ 14 25 33 6 84 14 
1° 45! 14 1g 3h 5 74 12 
ae 1 14 24 4 aye 84 
TABLE XVII. 
Speeds. 
if¢=0 if ¢=45° 
20 knots is equivalent to 50 yards in 43" a 
15 99 bb} bP) ve 10” 
10 ” ” ” 9” 13” 
5 ” ” ” 18” 26” 
A ship advancing directly end on at any of the speeds given in this 
table will increase or diminish the range by 50 yards in the time shewn 
opposite the speed in and under the column heading ¢=0. <A ship 
advancing obliquely at the same speed will not alter the range by 
