Sentinel Class Cruiser (1904)

The two scout cruisers of the Sentinel class were completed in 1905. This class is sometimes considered as one of four 2-ship subclasses (broken down by builders) of the Scout class cruisers.

Armament

Guns

As built:

• Ten 12-pdr guns
• Eight 3-pdr

After 1911/1912:

• Nine 4-in guns (4 on each broadside, 1 on CL aft)
• Six 6-pdr

Torpedoes

• Two 18-in torpedo tubes, above water

Fire Control

Evershed Bearing Indicators

This equipment was unlikely to have been fitted for gun or searchlight control.

Gunnery Control

Control Groups

"Scout" class Gun Control Groups

In 1909, these were described as being similar to the Gem class, but the forecastle and poop guns could be controlled as separate groups or attached to the nearest broadside group on either side. The middle line guns could be connected to whichever side was desired.

When the armament was converted to nine 4-in guns, the general control means created 4 groups:

1. No.1 gun port and starboard (these guns could be split out into groups 2 and 3)
2. Port guns 2-4
3. Starboard guns 2-4
4. Aft CL gun (this could be thrown into group 2 or 3)

Voicepipes permitted this scheme to be blurred further if required.

Transmitting Stations

The ships had a TS with 2 COS and 4 sets of transmitters.

Dreyer Table

These ships had no fire control tables.

Fire Control Instruments

Fire Control Systems
As shown in Annual Report of the Torpedo School, 1913.

By 1913, after their light 12-pdr armament had been traded in for 4-in guns, these ships were equipped with Vickers Mark III F.T.P. instruments for their sightsetting. The arrangements are documented in the Annual Report of the Torpedo School, 1913.

Their TS was equipped with 4 sets of fire pushes and transmitters with repeat receivers:

• panel 'A' addressed No. 1 guns port and starboard
• panel 'B' addressed the aft, CL gun
• panel 'P' addressed port guns Nos. 2-4
• panel 'S' addressed starboard guns Nos. 2-4

There were 2 C.O.S.es. The two No. 1 guns were wired through C.O.S. No. 1 with repeats on the gun side which had 3 positions, of which number 2 was regarded as useful only for switching over cleanly between positions 1 and 3:

1. both No. 1 guns on 'A'
2. No. 1 gun port on 'A', No. 1 starboard on 'S'
3. No. 1 gun port on 'P', No. 1 starboard on 'S'

The change-over was synchronised in this manner when splitting the guns for broadside fire:

1. get 'A' repeat receivers to the same range and deflection as 'S'
2. switch C.O.S. 1 to position 2
3. work 'A' to match No. 1 port's repeats to 'P'
4. switch C.O.S. 1 to position 3

The aft CL gun was wired through the second C.O.S. with repeat receivers on the gun side. It also had 3 positions:

1. aft gun on 'B' (its own)
2. aft gun on 'S'
3. aft gun on 'P'

The guns had continuous ringing fire gongs, and the fire pushes were wired through the C.O.S.es.

Voicepipes connected the control positions to the TS and to all guns. This could be used in parallel with the instruments to further divide fire.

See Also

• Wikipedia

Bibliography

• Template:BibUKARTS1913
• Template:BibUKFireControlInHMShips1919
• Template:BibUKDreyerTableHandbook1918