Dotter

Dotter
This is perhaps taken aboard H.M.S. Neptune, judging from other photos credited to the same photographer. You can see the wire from the firing circuit snaking along to the solenoid, and the frame with the target and scorecard near the gun muzzle.

The dotter was an assemblage of hardware conceived by Percy Scott to permit gunlayers to practice continual aim and to measure their success, all without expending ammunition. It became one of the hallmarks of Scott's transformation of Royal Navy gunnery and exemplified how his innovations were often syntheses of drill and equipment.

The dotter consisted of a frame in which a small moving ship target moved up and down as a gunnery drill instructor worked a handle. The frame would be positioned ahead of the gun a short distance, and the layer to be drilled would endeavour to keep the target centered in his scope by working his elevating handwheel. A pencil or pin on a solenoid attached to the gun barrel would plunge forward when the layer pressed his trigger, making a mark on a card. A perfect job of continual aim would result in a horizontal series of marks on the card despite its up-and-down motion along with the target.

See Also

• Director Trainer (equipment)
• Loader (equipment)