Ristodden - Oslofjord, Norway
 | Lighthouse category: beacon Position: 59º 43.1115'N : 010º 34.247'E Status: active Date: 2008 Designer: not known Tower height: 31 feet Construction: tubular steel (?) tower with lantern and gallery. Tower built on concrete base supported on tripod of steel piles Colour scheme: tower white with single horizontal green band just below gallery. Lantern white with red roof Focal plane height: 31 feet Characteristics: two red and one white sector, occulting ever 4 seconds Foghorn: none Google map view: google map link note: the Google Maps imagery was obtained before this light was constructed. The light itself does not therefore appear in the map but the arrow marks its position. |
It took me a considerable time to work out why this particular light - although it is clearly a structure of some substance and importance - didn't appear in any of my normal on-line sources. However, had I been sufficiently clever to spot it, there was a clue in this photograph! To cut to the chase - the clue lies in the condition of the concrete pier on which the tower stands. It is clear of any kind of dirt, salt or marine growth, and is obviously brand new. The light is one of several constructed during a major upgrade of the lights and other navigation marks in Drøbak Sound over the period 2007/08 so it had obviously only recently been finished when this photo was taken, and I'm not even certain that is was actually in operation at the time. The technical data given above were mostly obtained from the Norsk Fyrliste, so any errors are probably the result of my very poor knowledge of Norwegian rather than any technical innacuracy in the data. One thing that has puzzled me about the Norsk Fyrliste is that two heights are given, namely "Lyshøyde" which I interpret as "height of the lantern" and "Høyde over grunnen" which translates literally as "height above ground". Typically the latter is anything up to twice the former, so I can only assume that, in this publication at least, the true meaning of "Høyde over grunnen" is actually "height above seabed". The light is located close to the shore on the north east corner of the island of Håøya, at the narrowest point where the main shipping lane passes between that island and the island of Aspond. These lights were constructed by Secora, a firm owned by the Norwegian government. There sight has an interesting photograph here of work in progress on constructing the piles for one of the lights. From this photo it is possible to gain some insight into the method of construction of the tripod that supports the concrete base of the tower. Clearly the steel piles were first driven into the bed of the fjord, then the rebar was inserted, and presumably the interior was then filled with concrete.
The photograph below shows a wider view with the island of Håøya in the left of shot, the lighthouse in the right, and the coast around Sandvika to the west of Oslo in the background.
