We speak with Leighton rolley about his work at sea, discovering and documenting shipwrecks.
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Leighton rolley
Science technician at REV Ocean
Today we have the award-winning Leighton Rolley who has 20 years experience of supporting science operations at sea. he has found and documented dozens of historical shipwrecks. so, welcome to the deep sea podcast Leighton!
so in terms of finding a shipwreck, can you talk us through how you go about finding a wreck when you don't know exactly where it is?
It can be a really complex process, or it can be quite a simple one as well. In some cases, we have photos of a ship sinking with land in the background and you can match up that terrain and go out and map it. For example, with cases such as the USS Ward, you could see the terrain in the background so that was a relatively easy find. But for the ones out in the deep ocean, there's a lot more work.
And the older they are, the harder it becomes. With navigation nowadays, we all rely on GPS and equipment like that. But back in the old days when they had sextants and celestial positioning which would give you several to a dozen miles fixed, there's a lot of uncertainty. You have to troll through the history book and find as much information as you can. There's places like Kew Gardens and the National Archives in London which has thousands, if not millions of records on shipwrecks and stuff so it's a great place to start. I'm trawling the archives and putting all that information together and building a picture of what happened. Even things like what the weather was like that day. Going off of meteorological records and looking at current information from modern sources and as far back as we can, to figure out the standard weather in an area. Even on some of the more recent wrecks we've been doing, we've actually been applying mathematics. Things like Bayes theory for looking where the most likely location of a wreck is. Putting all that information into a mathematical formula to figure out where something is and the chances of finding it, if it's there. So there's a lot of research that goes on and trying to make sense of all the data - and there's hurdles in that. Some people forget that there's a difference between magnetic and true headings. You know, some people have gone looking for wrecks entirely the wrong places and so it's understanding the information.
The wreck of the Titanic - Image courtesy of Richie Kohler
I remember when they were looking for the USS Johnston and we talked about it on the podcast when it was happening. I think there was some confusion because when you get war wrecks you've got a report from the American side and an account of the sinking from the Japanese side, but they don't necessarily marry up. you're trying to work out which is the most likely and so on it's very complex isn't it?
We see that a lot yeah. Definitely between a lot of the fights around the Philippines, where you've got a American account and it totally differs. Like who scored what hit and when the hits occurred. I think around the confusion and the fog of war, that can lead wrecks to being dozens of miles away from where everyone thinks that they should be.
so what happens once you've narrowed it down? so you know roughly where it's going to be, where do you start in terms of surveying and honing in on the exact position?
Sometimes we use Bayes theory which will run thousands of simulations based on the information that's available and figure out the more probable location of where the ship is. If it's there, we can find it with the technology that we've got and then we'll plan the survey around the areas where it's most likely to occur. Now as I say, we use Bayes theory but sometimes you just go on a gut feeling. You know where all the information points to a location, sometimes it's just like: let's just start here and then and the search evolves from that. There's nothing better than hitting the wreck on the first go. Like with the Terra Nova, I think we found that in 40 minutes even though she was 20 miles away from where she was supposed to be. And there's this amazing reaction when you find it that early on. But some searches, they're just not in the right place, they're miles and miles away.
Terra Nova, photographed in December 1910 by Herbert Ponting
Is most of the the search work done using Acoustics?
In the last 20 years since we've started going to sea, there's different methods of finding wrecks and we have found them with hull-mounted systems. We did some great work out in the Philippines looking at wrecks in 300-400 meters using the ship's multi-beam. A big battleship when we hit it with sound, it's a big metal target so we get this information back: hey there's a big metal shape on the seabed! The deeper it gets and the rockier the terrain… if it's muddy or sandy it really causes issues there, so we can’t resolve some of the wrecks a lot deeper using those methods. That’s when we use other tools like autonomous vehicles (AUV's) which are like torpedo-shaped devices that have mapping systems. They take the sonar closer to the seabed so we can resolve those wrecks on the seabed. It's like a torch really, if you held it a meter above a table you can illuminate the whole table but if you bring it closer, you can really increase that intensity and see all the scratches on the table. That's really what an AUV does, it gets close to the seabed and we can see more detail. So, those wrecks that we can see from a ship, we can see when they're lying on the seabed using this AUV. But, they take longer to work so you have to invest more time in the search. But when they find a wreck they can sometimes map them (with the newer systems like synthetic sonar) to centimetre accuracy, so you can see the hits in the wreck, you can see damage, you can see ropes. They are phenomenal systems and we've come a long way in the last 20 years.
are there rules to this? when can you say for certain it's definitely that particular ship? Do you have to get that shot of the ship's name or can you go entirely on Acoustics - is the shape distinct enough?
You wouldn't just rely on acoustics. In most cases you want that… it's a terrible term “money shot” of e.g. for the Indianapolis the number 35 on the bow to indicate that is the Indianapolis. Or the name like Johnston on the ship or it's pennant number. If there's no other ship like it in the area, the Terra Nova, 57 meters long, wooden hull, wreck from Dundee, she's a whaler. You know, you can categorically say: this is that exact ship. But you really need to be able to prove it and there has been a number of mistaken wrecks where they've even actually gone down and the ship's very similar to another one and misidentified them, to be corrected later.
“There has been a number of mistaken wrecks where they’ve even actually gone down and the ship’s very similar to another one and misidentified them, to be corrected later.”
is there some sort of international body of shipwrecks where you go to them and say ‘I want you to register this because we've found it’ and therefore it's somehow on a record? or do you just put it out there and see what happens?
For military ships, there's a whole process where you would contact the admiralty and the naval historical branch and inform them that you've found that wreck. There are stringent rules for operating: there's strict no-touch policies, you can't take pictures of anything that could be clothing or show where there was a body lying. You can't penetrate inside a wreck, yeah it’s a war grave so there are laws that protect it.
I remember going to sea with you a long time ago, and you guys had stumbled across a Yugoslavian bulk carrier at 3000 meters. did you come across that by mistake or was that one of the ones you honed in on?
It was more of a mistake. We knew that there was a wreck in the area but we were also looking for seeps on the seabed. The one interesting thing about the wreck that we saw, it was a coal carrier and as it inverted and capsized, the hull had burst open. All the coal that had fell out from the ship, created a debris trail on the seabed that had a different reflectivity from the mud. The coal bounces back the sound and it was almost like a comet trail, and at the end of that trail was this area. Obviously a big metal ship reflects a lot of noise, that indicated that there was a shipwreck. But we were also interested in the seeps, so we dived down and confirmed that there was a lot of coal on the seabed and it belonged to this Yugoslavian bulk carrier. We never set out to find that wreck but you know… we identified it and we were able to say ‘okay this isn't a seep, this is a wreck’. And we do come across shipwrecks at sea just by chance. We've even found things like missiles and rockets and things from military tests. There's a vast amount of junk out there. And in other parts of the world, you find stuff where people have just sunk all their rubbish, so there's a lot of strange things we find down there.
assuming you've got the right tools for the job, is it easier to find a wreck in shallower water or deep water? because the size of the debris field gives you a bigger Target to get eyes on, right? but it's only big because it's spread out because it's fallen over such a huge distance.
Yeah, that's the good thing. You look at the Titanic's debris trail, and some of the wrecks that the hull got blasted apart on the surface and that that debris trail filters down. I think yeah a deep water can be a lot easier, the difference is depending where the shallow water is. For example, off Norway there's a lot of oil and gas. The shallow wrecks have generally been found during surveys there which are unrelated to finding the wrecks. So the deeper ones can be easier to find but it depends on the area, the depth of the water, there is a lot of variables but debris trails are fantastic indicators and help you find them.
how many wrecks are there? I read somewhere that it could be in excess of two million!
The wreck of the USS Johnston from the viewport of a submarine.
Yeah I think it was the UN report said there's around 2 million. That's from inferring what we just stumble across, what we know is out there. So there are millions of wrecks and sometimes you do just stumble on them and you have no idea what they are. You think little fishing boats from 200 years ago, they’re just timbers on the seabed and no one knows what they are. Or trading ships that just vanished into obscurity. The well-known ones, they take a lot of interest but there's a lot out there that we just don't know what they are. Everyone likes the famous ones like the the Lexington, the Indianapolis, the Johnston. They’re things where you can tie them to tangible history, although not always. People like the viking wrecks and stuff but some of the ones which have become popular like the Johnston, because there's so much written about those battles. We had survivors up until recently who can give personal accounts, and seeing the wreck can give closure to a lot of people. And then for us as biologists, you can go down and you can see colonisation of the wreck, or in some cases, how that wreck is damaging the environment around it.
“So there are millions of wrecks and sometimes you do just stumble on them and you have no idea what they are.”
we always think of shipwrecks almost in a romantic type of way, but it's still man-made litter. it is still something that shouldn't be there.
then at the same time, from an archaeological point of view, if you leave it where it is, it's going to dissolve. but then, what do you do? get a massive tin opener and just crack it open and take out all the good bits? you could preserve some of this stuff but that by doing it, it feels like you're desecrating it. but by not desecrating it, you're you're signing it's death warrant because it's never going to survive the seawater.
Yeah, that is a tough ethical question and greater minds than mine have pondered over that for ages. At what point does it become historic? Look at the Mary Rose, a fantastic ship that's been recovered and is now in Portsmouth. You think of that and it's a window into history gone by. You look at the Titanic; it is fading away, but should one company be allowed to own that and run shows and charge a lot to do it? Or should it be for the greater good that everyone can see it? And then you get to war wrecks, where people really want to know what happened to a specific ship. They want to put a flag back on there because the ship's still in patrol and other people want to leave it alone where it fell. I think it's hard with the war graves. You could go to France and you could visit the Samoa, or you could go to Passchendaele and see the brutality of war first hand. But for sailors, they have no marked grave. In this sort of case, they were lost at sea. Nature took their bodies away and the only thing that's left is this rusting hull on the seabed which the families in most cases can't see. So it's out of sight, out of mind. Although, there's a lot of people yearning to see it and then a lot of people not, so there's always a delicate balance and a big ethical question.
so out of Interest, what wreck is on top of your list right now?
Oh, I would like to find the wreck of HMS Glorious, a British aircraft carrier that was sunk during the evacuation of Norway. It's one of Britain's worst loss of life, with over 1500 killed onboard three ships. They were sailing back from Norway, basically the Germans had invaded the low countries. France was about to fall and Britain realised that it needed to consolidate its forces in the UK against the potential German invasion. So they were evacuating Norway and for some unknown reason at this moment, we kind of know what it is now, the aircraft carrier glorious was allowed to return with just two destroyers. On the way back, she just happened to encounter two German battleships that sunk them and it was a massive loss of life and there's so many unanswered questions in how this happened and what happened during the battle. I would like to find that and see the state of the wreck. It’s in the arctic circle, so it's kind of in the in the middle of nowhere in about three and a half thousand meters of water. So that would be a interesting one to find, there's been a huge amount of research done on that and thousands and thousands of records from the archives. So I think that would be top of my list but there's lots of other historic wrecks associated with older battles but it takes a lot of time and investment to do the research into finding something and I've got a day job as well, which is a supporting science!
HMS Glorious after she was converted into an aircraft courier.
yes that's the problem, it would be nice just to go about and find these things but yeah in the current funding climate, that's not an easy thing to get away with. archeology doesn't have the kind of money to support huge sea going Expeditions, with some of the most expensive gear you can think of.
Yeah, when you look at a ship, we're talking say 40 or 50,000 a day with the right equipment on there. And, some of these, you don't know where they are so you add in a 20-day survey or longer and that price really starts getting up.
Then you could add a caveat: we might not find it.
Yeah it is a high risk thing. Especially for ones where they just have historical value. There's organisations that go out there and find gold and it funds itself. If it's just for the historic value it's trying to convince someone that they should part with a few million to go and do it.
have you ever been involved in exploring these amMunitions dumps?
Dumped chemical weapons (Image courtesy of - Hawaii Undersea Research Laboratory)
I've stumbled across a few by accident. Our first was something off California. There was a lot of really nasty chemical weapons dumped off there and you could see it leaching into the seabed. But I've never actually gone to one of those areas and specifically looked at it. We found wrecks which have been sunk deliberately with things like mustard gas on, but again they really have no historical value. And as you say, they're like a ticking time bomb, biology-wise. They might be interesting but yeah, we tend to stay away because some people say if you go near there and knock something then you were the last person to touch it and if anything ever happens…
I just think it's fascinating from the same sort of philosophical question about how we use the sea and what's in it and how much we should disturb it, and so on. and I had the same feeling when someone showed me a confidential map of where all the known ammunition dumps are. even just around America, you're like: my God there's so many! just piles of bombs and missiles and chemical weapons. and that never really gets into the public Consciousness about what the sea has been used for, and probably maybe still is.
I mean you've dived to the deepest parts of the planet, there's a SR-71 in the Mariana Trench that they recovered, removed some of the sensitive stuff off and then threw back in. It was one of the first ones. It crashed and they threw it back in the trench. So, you know I think at that point, they were thinking ‘yeah it's not going to be that easy to get down there’.
One of the SR-71 planes that can be found wrecked somewhere in the Mariana Trench
oh I want to see that! that's the single coolest plane that ever took off. and it's in the Mariana? do you know where it is?
Uh no, but there's plenty of articles on it and you can see it just before they dumped it back in. But it had a bit of a high impact collision initially but it's back down there. That would be an interesting one to see.
are there any other great insights into into shipwrecks you want to share with us?
I think going forward, an organisation that does science nine months of the year but does a bit of wreck hunting to study the biology and the history would be an epic program. If you could balance the two, yeah I think that would be the way forward.
well Leighton, that's been absolutely brilliant and thanks very much for for joining us on the deep sea podcast!
Not a problem, thank you it's been a pleasure.