Almost four years to the day, the Loch Ness Cruises company published another sonar image of interest at the beginning of this month. The actual incident was on Sunday 22nd September. This is the account as described by the Daily Telegraph on the 4th October (original link):
I found Loch Ness monster on ship’s sonar, claims captain
Large object spotted by underwater technology reignites speculation about mythical prehistoric creature
A captain has claimed he found the Loch Ness monster using the sonar system on his boat. Shaun Sloggie, 30, was preparing his Spirit of Loch Ness pleasure boat to sail last month when a large object was spotted on the vessel’s underwater sensors. The outline, which was detected nearly 100 metres beneath the surface of the Highland loch, bears an eerie resemblance to a plesiosaur, which many have speculated could be the reptile group the fabled Loch Ness Monster belongs to. The footage has reignited speculation that Nessie, the creature alleged to inhabit the large body of water near Inverness, might really exist.
“I said: ‘What the hell is that?’” recalled Mr Sloggie of the sighting on Sept 22. “It was bigger than anything else I’ve ever seen. We’ve seen all sorts of fish that shouldn’t be here, but this? This was different. You should have felt the chills on the boat.”
Speaking to the Daily Mail, he added: “I’ve worked here for nine years and never seen anything like it. And sonar doesn’t lie, the boat hasn’t been on five whisky distillery tours before going out on the loch, it’s just doing its job.”
Mr Sloggie, who works for Cruise Loch Ness, said the object remained visible for two to three minutes and that he and maritime pilot Liam McKenzie, 29, were able to take a screenshot before it disappeared from the dashboard. He said it appeared in different colours, which are thought to indicate pockets of air and heat signatures which would suggest the object was alive. A previous sonar image captured on Loch Ness in 2020 was said to be the most “compelling” evidence yet of the existence of Nessie.
Mr Sloggie said the previous image was believed to show a creature “eight to 10 metres [26 to 32ft] long and one metre [3ft] wide” but speculated that the new object was “a lot bigger than that”.
The image was captured while the boat was close to the mouth of the loch, which Mr Sloggie said was the ideal location for a large predator to catch salmon and other fish going in and out.
“There are fish in the loch that shouldn’t be here. There are prehistoric creatures living in the loch and unknown codes of DNA, so there is room for mystery. This could change the angle of science on the loch. But how do you find out what it is? I’ve always known there’s something there. What it is, is a mystery. But it definitely springs open people’s imaginations. It’s not just about tourism, there’s real science in studying the loch.”
The shape of the sonar contact certainly stirred the imagination as some saw the shape of the classic plesiosaur in the picture. Indeed, who would not admit to seeing the long neck to the right, progressing to a bulky body with indications of flippers below and finally what looks like a short tail to the far left?
As to size, Mr. Sloggie offered an estimate bigger than “eight to 10 metres", which was the estimated length of the object in the prior sonar contact of 2020. He was later interviewed on TalkTV where he revealed that the sonar data had been sent off to the equipment manufacturers for expert analysis. We await the result of that investigation, but some were not content with waiting for the experts. Over at the Loch Ness Exploration Facebook page, we have this comment:
In fact, Dick has been busy on this topic trying to explain it away. Of course, everyone is entitled to their opinion and it seems not a few on these forums await Dick's verdict when such events arise. He latches onto some words Sloggie made in the Daily Express version of events (link) where it is said that the strange image "flashed up on the sonar on September 22 this year as they prepared for the arrival of another vessel."
Dick then concluded that reflections from the sonar device on the other vessel led to interference on Mr. Sloggie's sonar device and a compromised display image. So is it a matter of case closed, move on and no need for the manufacturers to get involved? Not quite, because Dick has not completed the enquiry in a scientific manner. He proposed a theory, but he did not test the value of that theory.
Since he does not seem willing to complete the scientific process himself, I will do it for him. Firstly, it has to be asked how close the other vessel was when the sonar image was seen? The answer is we do not know - based on the text quoted. Another image from the Daily Mail article shows what appears to be a GPS location image of the vessel Mr. Sloggie was on.
Given that the sonar depth of the object was given as about 300 feet, that is a depth consistent with bathymetric readings for that area of the loch. Why would his boat be waiting for the arrival of another boat from there? The likely explanation is that the narrowness of the canal into Fort Augustus meant another boat was ahead of them going into the canal.
The next question is how close do two vessels have to be to one another to produce meaningful interference? Does Dick know the answer to that question? I would guess pretty close given the size of the sonar cone beams. An important side question might be the minimum distance the authorities require between boats to avoid the possibility of a collision.
Moreover, interference requires that the two transducers have to be operating at the same frequency. The transducers are configured to tune into a narrow frequency band and looking at the bottom left of the sonar image, the boat was set to 200KHz. Note also the text "B260/M260" beside it which indicates the possibility of two transducers, one attached under the hull and the other on the inside of the hull. That may mean there are two beams of different widths complementing one another, but I do not have enough information to be sure of that.
So, the matter is far from closed on whether another vessel disrupted the sonar input and I am unclear as to whether the vessel used CHIRP multi-frequency sonar. In fact, interference seems unlikely consulting the words of others on the Internet. One website said this on proximity of other vessels:
When two or more echo sounders are operating in close proximity and at the same or similar frequency, it is possible for each to receive false returns from the others transducer. In such cases the operator will see noise and clutter, false returns, dotted lines, multiple bottoms or other video anomalies on the screen. This is most common in and around marinas or harbors where there may be multiple fish finders operating at the same frequencies.
This is accompanied by a drawing of such a display:
Does the Sloggie image show such patterns of interference? I would say it does not and that would make sense to me. After all, why would the intersection of two large beams result in changes to only a small area of the display and not affect any other part of it? The object of interest occupies less than 1% of the entire water column on view, surely we should be seeing more than that.
But herein lies a problem. For decades, such sonar images have been dismissed along the lines of corrupted sonar signals. We get words such as reflection, refraction and interference bandied about, but that implies such people have conducted calibrated tests to produce these images so as to use them when assessing future images.
In fact, the remit of the Loch Ness Exploration run by my colleague Alan McKenna is to record instances of common objects and effects producing hydrophone signatures which can be used to evaluate future recordings. I would suggest this extends to sonar. But why re-invent the wheel? Go to Adrian Shine and Dick Raynor to get their sonar data library on images known to have been produced by such sonar effects.
Now as for that tantalizing plesiosaur shape of the image, Dick further says:
The horizontal axis is indeed scaled to time, but it is not true to say that it provides no information on form or shape. I was wondering if the cruise boat had Raymarine's 3D visualization tool installed and ever use it? This is from Raymarine's Facebook page:
The lower 2D image may initially look like a jumble, but it is actually not far from what it actually was when reconstructed in 3D. Of course, it helped that the wreck was stationary on the sea bed. We do not know whether the object from Loch Ness was moving or just suspended in the lower depths. So, I await what Raymarine have to say about this and it would be great if some kind of 3-D rendering was possible.
Comments can be made at the Loch Ness Mystery Blog Facebook group.
The author can be contacted at lochnesskelpie@gmail.com
