Technical Analysis At Wn La Mare

Recently, Neil Walker and Malcolm Amy who generally volunteer at Stp Corbiere have stretched their wings to combine their interests which led them to an interesting workstream centered around Wn. La Mare.

Neil has for years been researching “all things optical” as many CIOS members will be aware. Malcolm, whilst not just having an interest in the Type 634 Bunker at Corbiere was fortunate enough to procure a very special optic from overseas that was pivotal to the operation of Sechscharteturme (or Mehrschartenturme) bunkers.

In fact the piece he acquired was in near mint condition both in terms of mechanical and optical attributes. the device in question being a moderately rare example called a Pz.Rbl.F.5 (Panzer Rundblick Fernrohr) or “Armoured Panoramic Periscope/Telescope”. Neil has discovered it also has been simply called a “Close Combat Sight” used by the cupola Commander for Observation and Fire Control Orders.

Last Friday Neil and Malcolm met at Wn. La Mare for initial testing to see if the optic would fit into the 20P7 Cupola. After some small adjustments to ensure the device would cleanly move past the aperture in the top of the cupola it was gratifying to find out that the restoration works from the Wn. La Mare team over the years included leaving the internal counter-weight inside the periscope support column in place.

After an absence of 70 and a bit years, the entire lifting system did work in a perfectly balanced fashion, much to the surprise of the two engineers on this occasion!

A short session follow taking some photos for later interpretation and assessing some of the Characteristics of performance, especially how the unit related to the rest of the components within the cupola.

With the use of captured German records, several points were uncovered and indeed doors were opened for even more learning to flow from these events. Wn. La Mare appears to be fairly well aligned although some question marks exist as to complete accuracy which will be assessed further as time allows.

In testimony to the build quality of the bunker, optics and the cupola, it was noted that after 70 years, slotting the optic back in and viewing the aiming reticules through the device pleasantly revealed the central azimuth scale to be perfectly aligned to the horizon! not bad considering how many variables could have affected this over the years!

Neil and Malcolm will continue to find out more with their co-work on this project. A big thanks goes to David Letto for being a primary guardian of Wn. La Mare and along with his team keeping the structure well maintained enough to give a real chance to allow the parts to be re-installed as close as possible to the set-up of 1945…..a true result!

Text and images by Neil Walker