Thursday 22 October 2020

The Latest Sonar Contact of Nessie


It has been a while since we had a sonar contact story from Loch Ness, but we have a good one here. The Mail on Sunday got a hold of the story and published on the 5th October. The gist of the main story is reproduced here for the record (these original links do sometimes disappear after a while) and I suspect the original print article had more information:

A sonar has detected a mystery 30ft long shape 500ft below the surface of Loch Ness - immediately sparking excited speculation from Nessie hunters. The 'solid and pretty big' sonar contact was picked up by a boat owned by Cruise Loch Ness. The mystery creature is likely to feed on trout and eels at the bottom of the loch, which has the largest volume of freshwater in Britain.

Director Ronald Mackenzie, 48, said: 'Who knows what it is, there is quite a lot of fish at the bottom of the loch, there is carnivorous trout and eels. I believe that there is something big living deep down in the Loch, who knows what it can be but I would love to think it's Nessie. It is something which is feeding on eels or trout. It is quite unusual.'

The mass was picked up around 4pm on Wednesday when Ronald was skippering a boat with technology from two years ago, about six miles from Fort August. The father-of-three added: 'A sonar expert has looked at it and says it's genuine. There is definitely something there. I'm going to give the image to the company which made the equipment to look at.

There were 18 'confirmed' sightings of the monster last year, making it the busiest year for claimed sightings since the peak of Nessie-mania in 1983. Last September, researchers from New Zealand claimed that the Loch Ness Monster could be a large eel, extracting DNA from water samples to test for this. Research carried out in 2018 revealed that the mythical creature is worth £41 million a year to the Scottish economy.

The Sun newspaper adds a few more details from Duncan:

We were at our halfway point off Invermoriston, where we turn around. The water is 620ft deep there. The passengers were quite excited because we had just spotted a sea eagle, but then I saw on the sonar something more eye-catching. It was right in the middle of the loch at about 558ft down. It was big – at least 33ft. The contact lasted 10 seconds while we passed over.  I’ve been on the loch since I was 16 years old and I have never seen anything like it. We have real state-of-the-art sonar on the new boat. It doesn’t lie. It captures what’s there. All the dots nearer the surface are shoals of Arctic char and deeper down there are ferox trout, so it gives you a good idea of the size of this large crescent shape.
Cruise Loch Ness posted the day after on their own Facebook page and monster hunter, Steve Feltham, has also been pushing this sonar contact on his own blog and talks about his involvement in persuading Ronald to release the image to the mainstream media. Cruise Loch Ness have been in the news before with their sonar contacts. Back in September 2011, Marcus Atkinson recorded an unusual trace near Urquhart Castle which generated some headlines as well. That article can be read here and is part of a sequence of articles over the last ten years following news of various anomalous contacts. I also wrote on their cruise business last year here.

I am not sure whether Ronald believes this is the Loch Ness Monster, but as a director of the cruise company he was keen to send it off for analysis to the manufacturers of the sonar hardware and we await further information. The article initially estimates the length of the object as ten metres or about thirty feet, which is a typical Nessie size. I blew up the image to full screen size and using a simple ruler against the depth axis you can see on the right hand side, an estimate of the area the object notionally occupies on the screen can be made. This comes out as about 2.3 metres per millimetre giving us a horizontal extent of about 9.3 metres and a vertical extent of about 3.4 metres or thirty by eleven feet.

I say notionally because dimensions are not all they seem on a sonar display. The depth at about five hundred feet can be taken as accurate enough using the depth scale. I estimate the object is at a depth of about 175 metres and the bottom of the loch is at 188 metres, so the object is about 570 feet deep and about 43 feet off the bottom. The problem is whether the object is actually thirty foot long and eleven foot thick and this lies in the fact that a sonar image is not like an optical image because though the vertical axis measures depth in metres, the horizontal axis measure time.

So what you may intuitively think is a large underwater mountain to the right of the creature is nothing of the sort for the loch is a flat basin. What actually happens is that the sonar machine under the boat sends out sound pulses at regular intervals at a frequency of 200KHz which are echoed back and analysed by the onboard hardware. Sonar records variations in density (water, gas, solid) and so what is rendered on the screen shows such variations. Now since animal flesh is mainly water, it does not register so well. In fact, when it comes to registering fish, it is their gas filled swim bladders that display the strongest signals on the screen. If this anomalous trace is a swim bladder, the overall creature would be enormous. But we do not know if it is a swim bladder.
Nevertheless, looking at the smaller specks on the screen, at the top near the surface and around the bottom, we can take these to be char, trout and eels amongst others. If relative size is anything to go by, then that gives us another ruler estimate that the contact is ten to fifteen times bigger than the fish contacts. Large fish sizes at Loch Ness can vary from one to three feet or more. But remember it is just the area of largest density variation that is being displayed. The actual object could be multiple times longer than the trace size and the more accurate vertical measure of over three metres is itself an indication of something large in the horizontal.

Going back to the overall trace, I can't quite remember if the constantly updating screen display goes from right to left or left to right. I will plump for left to right which means the oldest part of the display is on the right. Based on that assumption, we can see how the boat moved from deep water to the shore where the side wall of the loch rises to a depth of zero metres. Obviously, the sonar can only register land mass that is in water and not above. The peak then tails off and drops back down to about 200 metres and this is consistent with the testimony that they had reached the halfway point and turned around to head back into deeper waters.

The object then makes its appearance and then the contour of the loch begins to rise again suggesting the boat was moving a bit closer to land for a time, but not as close. I recall on my trip we stopped just off the Horseshoe Scree which is a bit south and opposite to Invermoriston. One well known Nessie sceptic who analysed this image suggested the new rising contour was the opposite side of the loch and hence this image was a complete profile of the loch bed from west to east. Using the known width of the loch at this point he calculated the object's width was a gigantic 50 metres - a number designed to cast doubt. This is incorrect as the boat would not have crossed that far over. This is an erroneous interpretation verging on disinformation and so we shall move swiftly on.

The next issue is the time axis and the dimensions of the creature. For example, if the object had stayed under the boat and tracked the same route as the boat, it would never leave the screen and form a long streak. One may presume the vertical size of the object would remain fairly constant. If it went off at a perpendicular direction to the boat, we may have a somewhat extended version of the object. However, looking at the zoom in of the object and its uniform crescent shape, there is a symmetry to the shape which suggests to me that it was closer to stationary that in motion. Note that smaller fish can also register this kind of crescent shape which may suggest a similar motion, though on this screen they are too small to be clear.

Since the horizontal axis is time, it does not measure distance. The display screen shows that the speed of the boat at the time of the snapshot was 10.7 knots or 12.3 mph or 18 feet per second. The witness states "the contact lasted 10 seconds while we passed over". So the object is bound within a maximum sonar cone with a diameter of 180 feet. But it is not clear what the speed was when over the object as the 10.7 knots was displayed further on and this would have been the speed quoted in the article. Since the boat would be heading off from a standing start at the turnaround point, it would be gaining in speed until the contact was hit. One assumption in all this is that one second of updating on the sonar screen display equates to one second of boat travel, which is not actually certain.
So what could it be? A large bubble of gas? The low decomposition rates and high water pressure at the bottom of the loch mitigate against this. Even if it was a gas release, this would travel upwards and so a angled vertical streak should be visible on the display as it heads up. A tree trunk floating over forty feet above the bottom? The abyssal plain of Loch Ness is very quiet and does not invite the kind of underwater currents that stir the waters above at the thermocline. To put it bluntly, no one has observed this phenomenon and it is not clear what a waterlogged tree trunk would look like on sonar as the variation in density with the surrounding water is far from that of a gas filled swim bladder. A shoal of fish seems unlikely at this depth and looks too "dense" to portray a loose aggregation of fish.
The manufacturers of the sonar will give their own analysis, but initial suggestions via Steve Feltham is that they think it is not a group of fish and it is likely a solid object between fifteen and twenty foot long. I would inquire as to whether that "solid" refers exclusively to the possible gas filled void or a larger estimate?

Now having considered various alternative explanations, one question to ask is where are all the other sonar contacts like this? If this is the best sonar contact in decades and we have various sonar-equipped boats sweeping the loch most days of the year, why have other similar contacts not been captured? Does the monster only pop up from the depths of the silt laden bottom a few times a year? That does not seem consistent with the amount of eyewitness testimonies on the surface over the last 87 years.

I suspect sonar hits such as this should not be as rare as the record suggests. I went over the discussions I have had with the Cruise Loch Ness crew in times past and this does indeed seem to be the case. When I went on a trip with them in April 2016, I was told by a crew member that they get large, anomalous sonar reading perhaps once every two years. On a return trip last year, a similar discussion with one of the older staff led to the statement that the boats have had about 600 sonar contacts over 10 years, most of those which were GPS tagged and when revisited were gone. That is one on average every week. Moreover, one crew member said he had once seen a sonar contact on the screen which required his thumb to cover it. That sounds similar to this latest contact!

That does not mean ever single contact is a monster, but I took a shot of an interesting blip on the sonar screen that day in 2016 which I reproduce below. The circular blip is seen above the big number "6". Measuring the object against the depth axis again gives a vertical extent of 3.33 metres or about eleven feet. The depth is estimated at about 130 metres or 420 feet. It is not as good as the latest image, but if I got that on a rare trip, what other interesting game changing images have Cruise Loch Ness obtained over the months and years but never get published? I was told that one of the senior crew has a private collection of these images collected over the years. I would love it if he released the best images to all Loch Ness researchers with no fear or favour for us all to pour over. 

The point being such a collection - not a single rare image - confirms that if there are large creatures swimming deep in the loch, you are not going to get one hit every thirty years. It is going to be a regular event and the images will range from interesting but inconclusive to very interesting and positive evidence. Let's face it, boats may be obtaining these sonar traces a lot more frequently than supposed, but they do not make it into the public domain unless they are more impressive.
So Steve Feltham says this is game changing evidence and "potentially the best indisputable evidence for large unidentified animals swimming about in Loch Ness". I think what constitutes best evidence in the eyes of each Nessie follower can be influenced by what genre they regard as most important be it video, picture, sonar or testimony. 

But I would say game changing evidence is determined with hindsight. For example, the Tim Dinsdale film was game changing evidence. We know this by what happened in the years following. Because people from all levels of society reacted to it in terms of attitudes and actions. The Loch Ness Investigation Bureau and all the other expeditions of the 1960s would not have happened if that film never saw the light of day. That is what I call game changing. Will this sonar contact have the same effect? I am not so sure.

I say that because we live in a much more sceptical age and the activity of the 1960s is unlikely to be reproduced as a result of evidence today. People are harder to convince today. What we may hope for is a like for like reaction. Various sonar manufacturers in the past have visited the loch to test their equipment. This may encourage some more to mount a more thorough and technical visit. However, the issue here is that the loch is already regularly swept by sonar by the various tourist boats from the top to the bottom of the loch and I suggest there are enough sonar images in the public eye or held in private. What are another few boats going to add?

The reaction has to be in superior equipment deployed at the loch such as the cutting edge Kongsberg family of autonomous underwater vehicles such as the MUNIN variant shown below which was trialed at Loch Ness back in 2016 when it found the remains of the 1969 Sherlock Holmes movie monster prop. The ability of this device to approach objects and areas of interest and thus produce more detailed sonar images is an obvious advantage to surface bound emitters.

The quality of the prop image below means a real monster could be resolved from a mere crescent shape to something approaching its real shape and form. There is however one problem as I found out when I contacted Kongsberg. If you want to buy such a sonar torpedo, it will set you back about £1,750,000 ($2,300,000). What if we just rented it for the duration of the search? That would be about £8,000 per day ($10,500) not including the specialists you would have to pay for to operate the complex equipment. 

That is probably not surprising for such cutting edge equipment and one would also have to consider how long the UAV would have to be deployed for in order to finally obtain a viable target to pursue? Days, weeks or months? A month's rent would cost £240,000! Also, could the monster out swim the maximum speed of the unit which is about six knots (7 mph)? Clearly, throwing such a large amount of money at this heightened level of search carries its own risks.

How game changing does evidence have to be to move some tech company, rich individual or sponsor company to put their resources or money at the loch's disposal? Only time will really tell on that score.

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