FAT artillery plotting board

[Gunner]

Hi Guys:

I'm having trouble figuring out the circumstances where an arty board would be carried in a gun tractor.

At the risk of being a little pedantic, the Gun Detachment Commander is busy enough commanding his gun... I don't think he would also be expected to do the TARA's (Technical Assistant, Royal Artillery- now shortened to Arty Tech or just Tech) job of plotting the gun position, the observer (Observation Party or OP) and the target and then doing the mathematics involved in spinning a plotting device.

There are three main parts to the indirect fire problem- the target, the observer and the guns. These form a triangle on the ground that has to be solved in order for the guns to hit something they cannot see. The guns are surveyed in and the OP sends his location as an accurate map spot to the command post (CP) at the guns. They now have two parts of the triangle solved. The OP can then send the target information as a grid reference or as a bearing and distance from his location. In either case you now have three parts of the triangle and can solve any other part with a bit of math. All this is done on the plotting boards in the CP. The guns don't actually do any plotting themselves. Added to the CP's work are the calculations for meteorology, curvature of the earth, spin of the earth, weight of the projectiles and any obstacles like mountains between the guns and the target. The description of the target will also influence the ammunition selected if not specified by the OP. These all result in a series of orders to the guns which include the ammunition, the charge of powder, the bearing to lay on, the elevation or range (depending upon the type of sights fitted to the gun) to hit the target and a method to control the fire ("fire for effect", "at my command", etc, etc).

Occasionally single guns or pairs of guns will be sent out to conduct independent harrassing fire (HF) or sniping gun (SG) tasks. They would be issued either a gun data sheet with the gun data (bearings and elevations, etc) or an officer and tech would go with them to become a mini-CP.

All of this is also why gun tractors don't normally have radios in them. Guns going on HF or SG tasks will be issued a manpack radio from 'Pronto' (the Bty Sigs NCO) for the duration of the task.

SP guns are generally fitted for radios as they are often deployed in more dispersed gun positions and the radios are used to pass orders.

Cheers and Ubique! Mike