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Mike Leahy's Med diary: Putting food on the table

Updated Thursday 27th September 2007

Mike Leahy sniffs out the solution to a mysterious tub.

Mike Leahy Copyrighted image Icon Copyright: Production team

Saturday 25th September - Day 1

Three months to Christmas. What an awful thought, but at least I didn't have to make any more dye. More to the point, I had an enjoyable project to look forward to.

Jonathan and I were to attempt to generate electricity. I got up at a quarter to six and walked up to the prison in order to get some time on my own.

Although I was tired, I enjoyed it immensely, and towards the top, where the track became smoother I ran.

On reaching the prison, I took off my sweaty vest and hung it up to dry. I was meant to have bought a second set of matching clothes for Programme 3 but had not found time, and the vest was the only piece of clothing I had that wasn't plastered in brand names.

I chilled out on one of the prison walls watching the sun struggle over the horizon, and it wasn't too long before I heard the dulcet sounds of the Land Rovers’ diesel engines pulling up the incline.

Time to get going!

My idea was to make a generator which produced direct current (DC), following the design of some early automobile units in which a coil of wire, supported on an armature is rotated within a magnetic field.

In fact, most of my work on the island was based on my previous career as a mechanic, rather than my current one of molecular biologist / virologist. Even so, both are linked by a common thread: the desire to find out how things work.

Jonathan, on the other hand, was to make a very simple (and in my view) small, alternating current (AC) generator.

His design incorporated a stationary coil of wire and he was going to pass magnets close to it, thus forcing the magnetic field across the conductor. Although his was an elegantly simple design, I was confident that my generator would function far better.

To get the armature or magnets turning we needed some form of motive power. Jonathan opted for wind power, but I fancied trying something different for when the wind wasn't blowing.

As there was no running water close to the prison, I thought that I would try to build a simple steam turbine. As I built my generator, Jonathan started on the windmill.

His generator was an integral part of the windmill's structure, and could not be built in isolation, whereas I could build my generator on its own, and make sure that I could produce electricity before coupling it to a power source.

By the end of the first day I had more-or-less finished the generator, and knew that it was whacking out about 6 volts and a good few milliamps.

On the other hand, Jonathan was halfway through building the windmill, and had no idea whether his design would be successful. To be honest, I thought that I was almost there, and didn't think that there would be any problem turning the thing. How wrong could I be?

Sunday 26th September - Day 2

I got up early and ran up to the prison again instead of taking the Land Rover. This time I could get on with my work. In a way this was pretty selfish behaviour, because the previous night we had been on a foraging tour, and had found some big barrels, and a pallet. I should have helped load them onto the Discovery, but forgot, and left the crews to carry the can (literally).

On arrival there was some concern over the nature of liquid that had been stored in the barrels. Would they blow up if heated? One clearly smelt of diesel, but the other was a mystery; strangely familiar, but not quite right.

At first I thought it was paraffin, but after my mind drifted back to the good old days when I worked in a garage workshop, I soon changed my mind to engine degreasant. A strange thing to find on such a tiny island.

Who would have used such a large barrel of the stuff? The important thing was that there was little risk of explosion once the barrels were half-full of water.

Petrol could have been lethal. I busied myself making a steam wheel, a bit like a mini waterwheel. Of course it was not exactly a turbine, but close enough. Then I tried it out by sticking it on the axle of the generator and aiming a jet of steam from a kettle at it.

No joy! To maintain an efficient magnetic circuit I had made the armature from some magnetic, but very heavy, sections of scaffold pole. This, added to friction from the simple wooden axle and bearings, made turning the generator a difficult business, so I tried to redesign the steam wheel.

Still confident that I could get enough power from steam under very low pressure, I persuaded Vanessa to give up helping Jonathan and help me build a bloody great fire to generate much more steam.

In the meantime, Jonathan was facing the opposite problem. Wind would readily turn the sails of his windmill, but his tiny generator needed lots of speed rather than turning power (torque) if it were to work, and at this point it was producing no electricity at all.

Eventually I finished my modifications and carried the generator around to the huge twin fires that Vanessa, and most of the film crew had built. The first thing that struck me was how much wood is needed to heat up the two 205 litre barrels of water.

The second was how crude the steam delivery hoses were. With no means of precision engineering, combined with my slapdash approach, it was going to prove difficult to sort out the details.

True to form the very roughness of construction b******d the attempt and I couldn't persuade the generator to turn for longer than a few seconds. More to the point, I was facing revolt. Vanessa, both film crews, and our esteemed producer could not keep up with the demand for firewood, and the steam and smoke were pissing everyone off.

Monday 27th September - Day 3

After two day's hard work, plus a run back to the hotel the previous night, I was tired, and took the Land Rover up to the prison. But if I was tired I was doing better than my clothing. The vest that I had worn the previous two days was gopping - the most disgusting piece of clothing one could imagine.

Today was the last chance to get the generators going. I had a generator without a decent power supply, and Jonathan had a great, if intermittent, power supply combined with a crap generator.

We did the sensible thing, and combined forces, resulting in an acceptable machine. We still had problems however. For a start, if the windmill rotated in the wrong direction (for example if the wind caught the sails from behind), the generator could easily be damaged.

Secondly, because the generator was made of very basic parts, the commutator caused bulbs to flash on and off, rather than give continuous light.

Even so the thing worked!

To end the programme we visited the lab to see what Anna and Mike had been up to, and found out that they had been producing anti flatulence medicine, and a hair restorer - both for me!


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