Tendring’s Semaphore Experiments


Signals launches interactive semaphore website to celebrate Tendring’s coastal heritage and connections with early experiments in long distance communication during the Napoleonic war.

Stop the ships from crashing into the rocks with our Semaphore inspired video game! Use your webcam and wave your arms to semaphore different letters and save the ships from sinking.

Celebrate Tendring’s maritime heritage and experiment with exciting new technology by playing games and learning local history. This new interactive website is part

 of Signals’

Talk Time project and made possible with a National Lottery Heritage Fund and Essex 2020.


Stop the ships from crashing into the rocks with our semaphore game!

The new Signals semaphore website celebrates Tendring’s maritime history by reimagening the technology to play games using a webcam and the various semaphore positions. Built by University of Essex MSc Artificial Intelligence student Benjamin Tilbury whilst on placement with Signals, the website uses a webcam to track arm movements and translate their position into semaphore signals. Players must spell words in time to prevent ships crashing into rocks or use the endless mode for creative writing with movement.

PLEASE NOTE: Currently the game only works on desktop (not mobile), we recommend using the Chrome browser for the best experience.

Tendring’s Semaphore Experiments

During the Napoleonic war the British grew envious of the French’s semaphore systems and began to develop their own. In the early 1800s various experiments took place along the Tendring coastline and along the chain of Martello towers and HMS Warning at Mersea Island.

David Neame from Friends of Jaywick Martello Tower researched one such story.

In an 1808 report of the Eastern district by General Twist and General Mann, it was stated that signal stations would be necessary to inform the war office of invasion on the south and east coasts of England. The report states that ‘As Walton Tower not only commands a view of the entrance into the Wallet but of every Vessel that passes up and down the Kings Channel, (the principal inlet to the Thames) it may be advisable to establish a Telegraph between that point and London, in which case more intermediate stations must be found than are named in the detail to shorten the distance of observation'[1]. [1] National Archives WO55/1548/3 Report on the Eastern District 22nd April 1808

General’s Twist and Mann devised a string of signalling towers along the coastline, starting at Walton and ending in London. To pass messages of any impending invasions, the Generals proposed three possible forms of communication;

  1. Smoke balls, which shall emit a column of smoke of that density and breath as to be distinctly seen at a distance of 40 miles.
  2. Pitch barrels (the ancient beacon) might be adopted with effect, and at night a composition of white lights in boxes of about 41/2 inches diameter fitted to copper sockets would fully answer the purpose.
  3. Flags – however this would require the number of stations to be multiplied, meaning the expense and probability of error would increase in proportion.

In 1810 the Admiralty began to experiment along the coastlines Martello towers. Due to how flat the Essex coastline it was hard to see land from sea. When you compound this with fog that often swept in during spring and autumn, they were struggling to “repeat” messages from the Tendring coastline across the Blackwater and Colne Estuaries to St Peters Chapel . In his book Britain Against Napoleon, author Peter Knight writes

To alleviate this they positioned a ‘leaky old danish gunship’ off Mersea Island and renamed it HMS Warning. Unfortunately this ship was very unstable and long-suffering captain Lieutenant Thomas Gill, ‘Found the vessel roll exceedingly heavy’.

As part of our Talk Time podcast, we spoke to David to find out more about the towers and their role in the Napoleonic War. Listen at the link below or in your podcast app of choice.

Design Your Own Communication Device

Feeling inspired? Why not design your own semaphore language! Remix this Scratch project and replace the costumes in the ‘text’ sprite to design your messages which pop up based on the positions of your arms.

Click here to try it out and remix your own version.