Thursday, 21 November 2013

Surveying at Portuairk

Sunrise at this time of year, when we have the privilege of seeing it, comes at about 8.30.  This was the view down the Sound of Mull this morning just as the sun broke the horizon.

On the north coast there was much more cloud, and snow still lingered on the mountaintops of Rum.  This picture looks across one of Portuairk's beaches, with Muck in the middle distance and - if it can be believed - a yacht sailing serenely towards Ardnamurchan Point.

The visit to Portuairk was partly to complete the initial excavation of the floor of the 'hut' on Jim Caldwell's croft.  As can be seen, only part of the floor has been paved - and a very neat job it is - while areas to both left and right remain earthen.  If anyone has any idea why this should be, we'd be very interested to hear.

We now need someone with archaeological qualifications to have a look at what we've found.

The rest of the morning was spent re-surveying what we take to be a house, possibly dating to the mid-19th century, and its surrounding enclosure.  Jim has recently bought a very substantial tripod off eBay, and has attached a plane table, so he did the complicated work while the Diary went round holding the survey pole, seen at right, made from a length of plastic drainpipe and some electrical tape.

The alidade is also home-made by Jim, out of pieces of oak.  As well as being an artistic masterpiece, it works perfectly.

We're still experimenting with different methods of surveying, so as well as the plane table and alidade we also used a system which relies on a protractor which has been aligned north-south, so that bearings can be read off for each of the survey points.  This second method seems to be far less accurate, but has the advantage of being rather more portable than the tripod and plane table.

Jim has volunteered to draw up the map.

Anyone wishing to join the Ardnamurchan archaeologists, please contact the Diary.


  1. I am interested in your photograph of the alidade, demonstrating its use. I have been searching for a picture like this to illustrate a historical article about map making that we are preparing to upload onto our open access educational website: Would you be happy for us to use the photograph? If so - do you have a high resolution of the image, and how would you like me to credit you?

  2. No problem with your using the image. Contact me at for a higher resolution image. Jon