WW2 Royal Navy Barr & Stroud Ltd MK-1 No.34 Naval Gun Direction Sight Binocular

The WW2 Royal Navy Barr & Stroud Ltd MK-1 No.34 Gun Direction Sight Binocular was a specialized optical instrument used as part of British naval fire-control systems during the Second World War. Manufactured by Barr & Stroud Ltd, a renowned Scottish optical engineering firm based in Glasgow, this sighting device played a vital role in improving the accuracy of naval gunnery.

Purpose and Role in Naval Gunnery

The Mk I No.34 Gun Direction Sight was not a standard pair of binoculars for general observation. Instead, it was a precision-mounted optical instrument integrated directly into a warship’s gun direction and fire-control system. It was specifically designed for installation aboard Royal Navy vessels such as:

• Destroyers

• Cruisers

• Armed merchant cruisers

• Transport and auxiliary ships fitted with defensive armament

These sights were typically mounted on stabilized platforms or director towers, allowing the operator to maintain visual tracking of a moving target despite the motion of the ship.

Function Within the Fire-Control System

During WWII, naval gunnery relied on coordinated teamwork and mechanical fire-control computers rather than automated digital systems. The process worked as follows:

1. Target Acquisition:
   The sight operator used the binocular sight to visually acquire and continuously track an enemy vessel, aircraft, or shore target.

2. Range & Bearing Determination:
   While separate optical rangefinders (also frequently produced by Barr & Stroud Ltd) determined distance, the gun direction sight was used to establish precise bearing and angular movement of the target.

3. Fire-Control Calculation:
   The observed data—range, bearing, speed, and relative motion—was transmitted to the ship’s mechanical fire-control computer (such as an Admiralty Fire Control Table). These systems calculated:

   • Elevation (gun angle)

   • Deflection (lead for moving targets)

   • Predicted impact point

4. Gun Laying and Firing:
   The calculated firing solution was relayed to the gun crews. The naval gun operator adjusted:

   • Shell type (armor-piercing, high-explosive, etc.)

   • Propellant charge (where applicable)

   • Elevation and traverse

   Once aligned, the guns were fired either locally or by director control.

Design and Construction

The Mk I No.34 was built for durability and precision in harsh maritime conditions:

• Heavy brass or alloy construction

• Weather-resistant housing

• High-quality ground optics

• Fixed mounting points for director integration

• Reticle markings for angular measurement

Unlike handheld field binoculars, this instrument was part of a fixed combat system and engineered for stability, accuracy, and repeatable precision under combat stress.

Please contact us for further information regarding the shipping of this item, as it is considered an overweight and oversized item. Shipping costs will need to be calculated accordingly.

The condition of the item is acceptable, regularly used, with visible sign of natural weathering due to it's long exposure to the elements at the sea and harbour during it's service life, a few missing bit bolts for the side panel, the gun directional sight is locked in place, visible paint peel and rust, visible crack on the optic lense.