NAS Side Scan Sonar course – Invergordon, 26-27 February 2022

A random ‘blog’ about a brilliant new course by NAS tutor and trustee Geoff Downer.

Friday the 25th of February; the joining instructions were to meet the boat MV Clasina at Invergordon Pier, Scotland.    

Southerners like me may not realise that Invergordon is in the Cromarty Firth, some four and a half hours north of Glasgow!

Despite the distances involved, several people duly arrived at the pier to find the pier itself was a whopping 1km long and the boat moored right at the end which made the total journey even longer!! Thanks to the team at the Port of Cromarty Firth for their help and assistance throughout the weekend, all of whom were keen to help with the project.

No matter though, after some transport issues were overcome, and the pub visited by some of us, we all got on board, were introduced by our NAS host Claire Hallybone, and a briefing received for the weekend. Our tutors Kevin Heath and Brett from Sula Diving sat quietly and eventually, with embarrassment, revealed that the cable for the ‘fish’ of the sonar had been damaged during the day and they were moving heaven, earth and the Scottish postal system to find and secure a replacement cable. The first upside of using professional equipment being that spares, service and support should normally be expected to be available 24 x 7.

So Saturday turned out to be a theory day, installing software onto laptops, learning how to use it and loading (real) data prepared earlier by Kevin to play with as we found our way around the software, punctuated by healthy food and a bottomless tea and coffee supply.

Meanwhile in the background Kevin and Brett worked like Trojans to collect and fit a new cable in time for us to do some real deployments on Sunday.

Sunday dawned bright sunny and importantly calm - a beautiful day not nearly as cold as we expected for late February in the far north of Scotland. We spent the morning “mowing the lawn” ie. going methodically backwards and forwards over the designated survey area. We used the NAS MOD Licence and undertook real side scan sonar surveys of our licensed HMS Natal and some other unrestricted targets inside the Cromarty Firth.

By lunch we had completed gathering the data and after lunch were able to load it into our software and start to analyse the survey data and start to make sense of what we had found.   Start being the operative word – all agreed that it would take many days to go through the images we had accumulated and even begin to understand what we had.

This was a superb course with a big shout out to Bob Anderson and his crew on MV Clasina for patiently ‘mowing the lawn’ in such straight lines and for their facilities and hospitality. Equally, to our Tutors Kevin Heath and Brett from Sula Diving, for detailed training, their obvious knowledge and patience in answering our questions and lending us the hardware! 

This course gave me a massive step forward in my knowledge and I'm sure the other participants agree. It took us into the use of professional equipment for underwater survey and by our own estimates saving days of diving to conduct the basic location and outline surveys of the wreck.

I strongly recommend NAS offers this course again in the future – possibly not quite so far north!


Geoff Downer