Independent line of sight

 

 

The independent line of sight meant that two gunlayers were used, one on the right side controlling elevation, one on left controlling the range. This speeded up gunlaying, especially with direct fire against at moving targets, and increased the rate of fire. It was first brought out by the French in their 75mm Mle 1897 field gun, and was later adopted also by the British army. Although both Krupp and Rheinmetall had introduced carriages with sight of this type, the German army did not appreciate them.

The difficulty of fitting reciprocating sights to carriages of this type was an objection against its introduction. Moreover Germans military experts emphasized that the advantage of the independent line of sight was scarce, thinking that the question of rapid fire in the field artillery had less to do with slow laying operations than with preparating ammunition.

Usually the armies which bought French guns choose the independent line of sight, while who adopted German guns, preferred the ordinary way of sighting, where all laying operation were performed by one man, the gun layer. The main exception was Bulgaria, that required that its Schneider field guns had not independent sighting apparatus: the sight and aiming circle being attached to the cradle, both moved in elevation with the gun.

 

The quadrant elevation of the piece consisted of two parts:

-     the elevation necessary to reach the target if it were on the same level as the gun.

-     the correction to this elevation required by the difference of level of the gun and target (angle of site).

With the independent line of sight the two parts of the quadrant elevation were applied to the gun independently. An intermediate rocker and two elevating systems, A and B, were provided as shown in the picture. The sight was fixed to the rocker, and for direct fire the gunlayer handled the lower elevation system (A), which moved the rocker as well as the gun in elevation. In this way the angle of site was automatically corrected, when the line of sight was brought upon the target.

The other elevating mechanism (B) was between the rocker and the gun and was handled by another gunner who elevated the gun until the proper range appeared on a range scale. The change in range did not affect the setting of the lower elevating mechanism, and the gunlayer was thus free to devote his whole time to keeping his line of sight upon the target, without being compelled to take his eye from the telescope. The above method has the objection, however, that it is difficult to make the necessary correction in the range drum for difference in level of trunnion axis.

 

 

 

Artillery equipments at the beginning of World War I

Country

Maker

Calibre

Adoption year

Field guns fitted with independent line of sigh

Argentina

Krupp

75mm

1908

Chile

Krupp

75mm

1910

China

Skoda

75mm

1912

Great Britain

Vickers

76.2mm

1903

Great Britain

Vickers

83.8mm

1903

France

Puteaux

75mm

1897

France

Schneider

75mm

1912

Greece

Schneider

75mm

1906

Italy

Krupp

75mm

1906

Italy

Krupp

75mm

1911

Italy

Deport

75mm

1911

Mexico

St. Chamond

75mm

1902

Portugal

Schneider

75mm

1904

Russia

Schneider

76.2mm

1913

Serbia

Schneider

75mm

1907

Spain

Schneider

75mm

1906

Sweden

Krupp

75mm

1902

Field guns not fitted with independent line of sight

Austria-Hungary

Skoda

76.5mm

1905

Belgium

Krupp Cockerill

75mm

1905

Brazil

Krupp

75mm

1905

Bulgaria

Schneider

75mm

1904

Denmark

Krupp

75mm

1902

Germany

Krupp Rheinmetall

77mm

1896/1906

Holland

Krupp

75mm

1903

Japan

Krupp Arsenal Osaka

75mm

1905

Norway

Rheinmetall

75mm

1901

Romania

Krupp

75mm

1903

Russia

Putilov

76.2mm

1900

Russia

Putilov

76.2mm

1902

Switzerland

Krupp

75mm

1903

Turkey

Krupp

75mm

1903