A very rare cased variety of convoy clock, the only one from famous outfitters Henry Brown & Son we’ve seen in our 50yr history. Amazing condition and complete, a collectors dream. The MV Darro was a British refrigerated cargo ship launched in 1942 and completed in 1943 for the Royal Mail Lines. It was primarily used for transporting perishable goods and passengers between the United Kingdom and South America.

An unsung hero. What is a Convoy Clock?

Zig-zag sea routes came about in 1917 when German U-boats prowled the Atlantic  and North Sea. Instead of traveling in predictable straight lines, the British Royal Navy ordered groups of ships convoys to zig-zag their way to their destinations. Zig-zagging confounded the enemy’s efforts to track a convoy’s route, speed, range, and position. Submarine captains couldn’t be sure how to position their boats to fire their torpedoes with effect. Sailing with their British allies, US ships adopted the practice, which continued through World War II. 

Each ship in the convoy had the same clock, synchronized with the flagship, and attached to an alarm system in the bridge. It looks like an ordinary clock except for the little metal pegs or clips around the rim that could be moved into different positions. When the minute hand swept past a peg, the alarm sounded, indicating both a speed and course change. Ten to twenty minutes later, it would sound again for another correction. And on it went for days at sea, each ship’s bridge buzzing or ringing in harmony to keep the convoy moving together. 

Here is a colourful first-hand description of a convoy zig-zag operation during WWII:

This mighty collection of vessels, occupying ten or twelve square miles on the ocean, skillfully maintaining its formation, was really a beautiful and inspiring sight. When the destroyers had gained their designated positions. The splendid cavalcade sailed boldly into the area which formed the favourite hunting grounds for the submarine”.