Marine Peilstand (Naval Direction and Range Finding Towers)

Introduction To Marine Peilstands

An unusual type of fortification, unique to the Channel Islands. Marine Peilstands, or MP for short, are German Observation Towers, typically used for rangefinding and observation. It would take two towers to triangulate the position of a target. Each floor of the Marine Peilstands was designed to serve a different Naval Batterie. 5 Naval Batteries were planned but only 3 were completed. At the peak, 11 Marine Peilstands were planned, however only 5 were built. The towers use a numerical numbering system, consisting of MP1, MP2, MP3 and so forth. Out of the original 5 built, only 4 remain. MP1 was collapsed into the Chouet Quarry in 1991. The towers don't seem to follow similar constructions. MP1 and MP3 were almost identical, MP2 is similar but built on the base of a Victorian Tower, MP4 is unique and a very unusual shape, MP5 is odd-being built on top of a 19th Century Mill.

How Did They Work?

Pythagoras Theorem is a law of mathematics, stating that if you have a right-angled triangle with lines A and B, and hypotenuse H, then the sum of the square of A and the square of B is equal to the square of H. The towers used this to construct a right-angled triangle between two towers and the target, using this they could determine a position of the vessel. This position could be relayed to HQ Bunkers and Fire Control Towers at Naval Batteries. Then one of the three batteries would eliminate the target, This process worked better in theory than practice. Interestingly, the towers are positioned in relation to each other by the exact kilometre. 

MP4 - MP3 = 1km

MP3 - MP2 = 3km

MP2 - MP1 = 10km

MP1 - MP5 - 2km

This was likely done to make the calculations easier. Sadly most of the range finding equipment has been removed from the towers