This was an 'accidental' purchase. I came into contact with a man who was selling a station pointer (and a sextant). As I was interested in the station pointer I went to visit him. When we started to have a discussion we got round to professions and I explained I was a hydrographic surveyor. Turned out he used to be one as well, working for the Delft Hydraulics Institute when they still did their own survey work. When that department was closed at the end of the 1970s (I think) he took home all the instruments to prevent them from getting binned. What I found was that he still had them. As he was soon to move houses (and was already into a well deserved pension) he had no issues donating all his instrumentation to me.

So while I came to pick up a single station pointer, I went home with the trunk of my car full of survey equipment. Most of that was drawing materials (which will show on this site eventually) as well as two veyr similar tide gauges of the type shown here. One of the two is in store at Skilltrade where I use it for demonstrating the 'old fashioned' tide gauge to my students. The other is a permanent part of my collection.

This instrument was designed to be as portable as possible as the survey department of Delft Hydraulics (now Deltares) did most of their projects in remote locations. When compared to the HO pressure tide gauge also in my collection it becomes very obvious what portable means (this one) and what transportable means (the HO one). To give an idea of size; the white square on the bottom plate is for a single C-cell battery which drives the clockwork. The pressure gauge is of the balloon type and connected using a very thin plastic tube to the instrument. The pressure differences are transferred in the instrument into a mechanical movement of the pen (laterally). Due to the movement of the paper a tide trace is created. It is a very elegant, yet still sturdy and portable design.