Becoming an Amateur - Part Two

If you've read Part One you'll know there have been attempts to belittle the work, equipment and skills employed in finding the Bluebird wreck and recovering Donald so he could be given a proper burial. The search and equipment is not something I've really written about before so it's worth doing for its own sake as people might find some of the background of interest.

It's also worth adding it to the truthful historical account we're building here because what the RM doesn't seem to have factored in is that, should they generate an interest in K7 in any one visitor, that visitor sooner or later arrives on our website. At the moment the museum is withholding great tracts of the K7 story from the visiting public so the truth regarding the points set out below can be read about here instead.

1. The location of the wreck was known to many people so locating it was no achievement at all. That's just utter rubbish.

2. The equipment used was nothing special and widely available so nothing clever there either. Read on and decide for yourself.

3. The skills were neither here nor there so any diver could have done it. That's next on the list as well as a substantive response to their ridiculous open letter.

I've heard the same old things before down the years, invariably from people who either don't have a clue what they're talking about or who just want to be spiteful.

The truth of who knew, or rather didn't know, where the wreck lay is now here on the public record and will remain here, so now it's time to take a look at the next point, that being whether the equipment used was nothing out of the ordinary and that which any diver might be expected to own.

Bearing in mind the search began in 1996 some of the kit is now outdated but at the time it wasn't.

Let's begin with navigation because without navigation you're doomed from the get-go.

Finding your way around the globe is dependent on two sets of lines. Those that start and end at the poles and cut the globe into segments like a Terrys Chocolate Orange. (I was going to do the BBC thing and say, other chocolate oranges are available, but I'm not sure that's the case)

Those are lines of longitude. There's 180 of those and we have the first one at zero degrees passing through the Grenwich observatory. From there you can go 180 degrees east or west until you hit the international date line on the other side of the world and start coming back on yourself.

Then there's latitude. These are hoops around the world with the biggest one at the equator and the smallest at the poles so you go from zero degrees latitude at the equator to 90 degrees north or south at either pole.

Okay. Next, each degree is broken into 60 minutes - not minutes in time but minutes of an angle, and each minute is then further broken down into 60 seconds but one second of one degree of latitude is roughly the length of a football field so no good for looking for a 25 ft hydroplane with its front 8 feet missing so instead of using seconds we used thousandths of a second. This is much more like it because a thousandth of a second of latitude works out at about 2m. Longitude is a little more because the world isn't a perfect sphere and the lines of longitude converge towards the poles but for the sake of this discussion it makes no difference.

So if we choose a spot around Coniston Water say, the Ruskin Museum, it's at 54 degrees, 22 minutes and 214 thousandths of a second north and 003 degrees, 04 minutes and 580 thousandths of a second west. Plug all that into your satnav and it'll get you there. Best also to learn your 16.66 times table too if you're working with older positions in deg/min/sec because multiplying by 16.66 will give you the decimal equivalent in thousandths. There's other ways to navigate but that is what we worked with between 1996 and 2001 and again for four months in 2007.

Then there's another small matter to deal with because there's a couple of choices of what model of the world you're going to use. You really ought to choose one and stick with it so anyone using your data in the future doesn't hit snags. There's WGS 84 (world geodetic system 84) which covers the whole world and is OK to use but in the UK we tend to use the OSGB 36. Ordnance Survey 1936 datum. That way any data we produce marries up with our local maps.

So now we're good to go. But how to measure these numbers and work out where you are? We're all used to our car satnavs and telling our phone where we want to be and generally take it for granted but that often relies on GPS and that wasn't always there. When I started diving and looking for shipwrecks it wasn't something we could use. We relied on the old Decca radio navigation system and it was pretty good - on a good day, but GPS or Global Positioning System was the new fangled thing with satellites and everyone wanted it. Unfortunately it was completely useless. The idea is you tune into a constellation of satellites all timed together with very accurate atomic clocks that fire radio waves at you from space. Your GPS receiver then works out how far away each one is and calculates where you are on the face of the earth and how high up you are. Except it's an American military system and they wanted to keep the accurate part all to themselves so the signals us boat skippers got were deliberately degraded such that the best that could be achieved using GPS alone was about 100m accuracy and that's hopeless. You can lose a very big shipwreck with that kind of error and forget searching of any sort. It was called Selective Availability (SA) and, though GPS was around for a long while you didn't find it navigating cars until the 2000s and there's a reason for that.

The plan was that the Americans would have pinpoint navigation anywhere on the globe but their enemies weren't going to profit from it. Mariners did well out of it on long sea passages but around harbour or the coast it might put you ashore so an answer was soon found.

Differential GPS or DGPS. It's a very simple fix. What they did was set up shore stations with very precisely mapped locations then plonk a GPS receiver there and ask it where it thought was. Armed with the difference the shore station could calculate a correction and broadcast that as a data string to any DGPS equipped receiver and hey-presto, 2m navigation at your fingertips.

That's all well and good but now it meant that anyone could use the system to its fullest potential. Hmm, bit of an own-goal there, Americans. DGPS had to be killed off so in May 2000 the SA was switched off and suddenly it was good enough to navigate your car and if the Americans so chose they could degrade the system if war broke out. The Amazon parcel delivery drivers would be snookered, mind you.

So quite early on we bought a good GPS receiver and also interfaced a chart plotter for working off the Tyne or the Clyde - two of our happiest hunting grounds. Chart plotters were in use with the trawlermen and professional mariners but divers weren't into them at that time so we were ahead there.

Naturally you need all of this equipment to work properly but the DGPS receiver we had used thus far struggled so far inland so at great expense I bought a new one especially for the Bluebird search.

That was at 1996 prices and no one we knew had one of those in the sport diving community. It was the proper bees-knees and before I was allowed to buy it I had to sign a declaration that I was not part of or affiliated with any terrorist organisation! How many terrorists must have been thwarted by that one document?

We built the GPS receiver, DGPS receiver and chart plotter onto a single mount that could be fitted to either boat.

The yellow box is the DGPS and the silver one has the chart cartridge reader inside. Now it's all on a single laptop or monitor but back then that wasn't how it was done. It's all waterproof too because it could get a bit exposed out on the RiB

So that's the nav sorted out but it's all pretty useless without a boat. We could use the little 6m RiB and it was equipped to run all the same kit as the big boat, Predator, which has a nice warm wheelhouse, an outdrive for exceptional manoeuvrability and a turbocharged Toyota Land Cruiser engine making her good for 28 knots. She's also just small enough to go on a trailer and pull behind the Land-Rover. In actual fact we found K7 from the RiB on a rainy and dark October evening with a clear plastic bag over the monitor but that's another story.

All of this gave us a choice of boats we could navigate with deadly accuracy to find lost things on the bottom of a lake or in the sea and the kit thus far described, as you can see, was nothing at all. Most of it came out of Christmas crackers or was cobbled together from old broken bits we found in people's gardens alongside discarded Dysons and collapsed Argos TV stands and we had to use a pop bottle full of diesel and some old jump leads to find wrecks - as you're about to find out.

What do you actually look for shipwrecks with? It's lot of hard work with only a depth sounder.

As it happened, we'd become very adept at finding iron shipwrecks with a device called a magnetometer and the way ours worked is this. If you encircle a bottle of hydrocarbon fluid (diesel will do) with an electromagnet and energise it, all its molecules will line up and there they will remain for a short while before the order gradually decays, so energise the coil every two or three seconds and you get some nicely ordered molecules that will soon go all disordered if there's any other magnetism about.

Our mag fish - From memory, Aquascan Bob used to make these from gas piping and, yes, it is really full of diesel. I would love to know how many hundreds, if not thousands, of miles we towed this thing with the mag rhythmically going beep, beep, beep besides us.

While you're cruising around with nothing but the earth's magnetic field to worry about not much of anything happens, but smash up a big steel shipwreck all over the seabed and it wreaks havoc. The lines of earthly magnetism go all higgledy-piggledy and if you pull your tube of magnetised diesel through it, it goes all higgledy-piggledy too and in so doing induces a few microvolts in the coil that can be displayed to the operator.

Our old mag. It all still works and would find you a shipwreck today even though it's all over 20 years old now.

If you want to find iron shipwrecks at a diveable depth, and even wooden ones, because they still contain enough iron to make them findable, then a magnetometer is the go-to tool. Forget all the fancy sonars and get a mag - only it didn't work on Bluebird.

We'd found corroded engines on the seabed from which the wooden boat they once powered had long since rotted away. We found lumps of pig iron ballast from lost sailing ships and old anchors but when we scoured our search grid in Coniston Water it contained only one target and it was small. We weren't expecting the mag to scream and jump about over a small boat with a steel frame and aluminium skins but we were totally confident it would be easily detected by the mag. Not a chance.

The one target we did find was carefully boxed in until we had it in a very small area then, lo and behold, what did we see? A rope coming towards the surface, the mystery rope. We quickly put a diver down to secure another length to it and lowered our underwater camera to see what was on the end of it. Did I mention the underwater camera? Just a camcorder in a poly bag on a string.

It wasn't Bluebird, down there but we'll get to that.

Having so far exhausted our arsenal without result, we went big rather than go home and rummaged in our kit bags until one of us turned up a sidescan sonar system - don't ask to see the receipt for that!

Sidescan is a mythical thing, and massively overrated in many circumstances. Many people imagine that you just pull a torpedo on a string behind you and watch the seabed and everything on it roll by on a screen. Admittedly it can be like that because it's so ridiculously easy to use and a baby could do it but that's also for another day.

The first one we used didn't really come out of a kit bag because it was bought from an equipment rental company as it was coming off their inventory. Sidescan was from the world of oil and gas exploration and ours was very probably the first in the hands of sport divers and to this day sidescan is still rarely found in that environment. Our Imagenex, above, was pretty basic but still a powerful tool and when we needed more grunt we'd rent a Geocoustics system. That was a full-on professional survey system that any weekend diver might have lying around the garage but, strangely, no one did so we rented. By the time we came back in 2007 we'd thrown together an old toaster and a set of Christmas lights to develop our own sidescan that operated over multiple frequencies and went on to be sold worldwide by Tritech International.

Look, I'll show you. This is the original prototype of our first crack at making our own sidescan.

We began with a collision avoidance sidescan made by a company called System Techologies in Ulverston.

ST was run by two extremely clever engineers, Marcus Cardew and John Trepte, who seemed able to design sonar and write code in their sleep. I first met Marcus when appearing as an expert in the Lady in The Lake murder trial and we hit it off straight away. The trial was held in Manchester Crown Court and I'd drive down so I gave Marcus a lift back to Ulverston where he was kind enough to show me around his factory, I was like a kid in a sweet shop. Most of their kit was marketed by Tritech International in Aberdeen for use in oil and gas exploration so they were soon interested in what we were up to.

The collision avoidance sonar was designed to be strapped to a work class ROV (Remotely Operated Vehicle) and powered from the vehicle itself. It had no data logging capabilities and existed purely to make sure you didn't prang your expensive ROV into an oil rig leg. But the image quality was exceptional and we wanted to build a towed vehicle with all that exciting capability but this presented a couple of problems. We'd need data logging or it was all pointless so the software engineers at Tritech got to work sorting that out. Its power supply was also no use for towing on the end of a long cable because of the voltage drop over 300m of thin tether so Marcus beefed that up. Meanwhile, we made the above rig to alter the transducer angles to optimise its performance as a mapping tool and hauled it around the North Sea. Now it could look down instead of only sideways. That resulted in our first towfish. A great hunk of stainless, but it was successful so far.

The structure at the bottom has two transducers bolted to it at the optimum angle. The transducers are what fire the sound into the water. The green plug connector is for the right hand side 'ducer. Green for starboard, and it all fits inside the stainless tube above with a bottle of electronics to make it work.

A fancy coat of offshore-exploration yellow and it was time to beat it to death in the ocean to get the whole system working. We also built a computer for it in a Peli Case so we could easily chop and change and modify. We'd use a laptop now but we wanted as many options as possible back then.

You can change the graphics card at sea in a gale in there. Not so much with your laptop.

The controls bottom right with the array of black knobs was made by ST and was officially called a RAT. What didn't go into the official literature was it earned that name because it was, known as, and I quote, 'a f***ing big mouse'.

It has all the controls to put just the right amount of sound into the water and stay across that in real time. It unclips and can be carried around the wheelhouse. Above it is one of those vandal proof keyboards you get in cash machines or whatever. It meant that even if we dropped our keyboard in saltwater and stood on it, it didn't care.

Once the software was all done and up to speed we were able to use a laptop in place of the Peli Case if nothing was going to get soaked.

Next, the towfish was redesigned into a marine grade aluminium body and given a thorough tank testing.

It has all the same parts inside but a in a much more elegant package and while this was going on the software was being tweaked and honed.

We worked closely with both ST and Tritech who gave us incredible support and also took a lot from us hammering their kit in real-life scenarios. I remember asking the software engineer if he could make a slider on the screen a bit wider. He said if he did that it would reduce the amount of data I'd be able to to see on the screen but I said I didn't care how much I saw in real time as my only interest was in not crashing the fish into the seabed and making sure the data was of the best quality I could achieve. Looking at it would come later in the office with a nice cup of tea so losing a slither that was logged but which I couldn't see at the time wasn't a problem. The other issue was that grabbing the slider with a mouse pointer on a rolling boat was really difficult. Those things didn't happen in the lab so we got the slider widened and it worked nicely.

The finished job.

And it worked too. This is a wreck off the Tyne. It's a steam tug called Hercules.

Shot at 675kHz you can clearly see the deck beams and the steam engine, you can even see the sponges growing around the bow. The scouring on the seabed is quite striking too. Tritech went on to sell that fish as its own product for a lot of years and I remain very proud of the work we did on that.

But having sonar data is only part of the process. It's only any good if you can properly process and interpret it so you need some sort of post-processing software. To that end we used Coda Geosurvey, a full-on professional post-processing suite that cost about seven grand - then. But it meant we could take raw data captured out on the ocean and make it into pretty pictures like you see above. More of that in Part-3.

And it didn't end there - we brought two scanning sonar systems to the party too. They, as everyone knows, grow on trees so that was easy. One an Imagenex and the other made by Tritech (Marcus designed it and nicknamed it the 'bean tin' sonar because of its size and shape so maybe this is where the idea came from that our equipment list was all commonplace stuff).

See the blue thing poking out of the top of the road cone? That's a scanning head. There's quite a lot of other stuff lying about the deck too.

They were both very powerful weapons and it was the scanning sonars that allowed us to find Donald after 34 years on the lakebed, another trifling afternoon out but worth a mention, it's a wonder no one thought to do it sooner. History recorded that we found him on the 28th May 2001 but that's a lie. Must put that right in due course.

The scanning sonar isn't towed, it sits on a structure (we tried a few ideas before deciding the road cone made a perfect base) in one place on the bottom and scans around itself rather like a radar on a ship. Being static, it gets around many of the problems of a towed sonar, except that if you want to look over there you have to pick the sonar head up and go over there, but how to use it is for Part-3 too.

This was a very common sight in our wheelhouse.

This is the scanning sonar screen. It was usually left running because it let us watch everything that was going on down on the lakebed. If we had divers down or ROVs we could see where they were and what they were up to.

We also introduced ROVs to the inventory and USBL (Ultra Short Base Line) acoustic navigation to keep track of them under water. All things you can get in the middle aisle at Aldi.

We used two ROV's. Ours, which was pretty basic and manned mostly by Capt. Connacher (see the team page), and would often have to be recovered thick of weed because he'd fly it low down.

And the other belonged to Marcus who added on-board sonar, a manipulator and his own, home-made acoustic navigation system, as you do.

He also built a bespoke top-side box and sometimes flew his little robot using a PlayStation controller.

Clever chap, is Marcus. Below he can be seen launching the transducer for the acoustic navigation system. That pinpoints the ROVs on the bottom. Notice also, on the wheelhouse roof, is the DGPS antenna.

One final piece of kit worthy of mention is the rebreathers. BBP was the first all-rebreather expedition. Rather than carry bottles of compressed gas to breathe in once then blow bubbles with every breath, the rebreather, as the name suggests, recycles your breathing gas, chemically scrubbing out the CO2 and topping up the oxygen as required. it's a little life support machine, but hey, anyone can use one. I'll do a separate write up on the 'breathers as they're a subject all on their own.

So that's a quick look at the kit used so now you can decide for yourself whether it's commonplace or not.

In the meantime, Ruskin Museum, whilst aiding the public in properly interpreting all of Bluebird Project's amazing work, should there be anything you've left out regarding what equipment we employed in the successful search for Bluebird and Donald Campbell, you may use the above to properly inform your visitors.

Bill