”Ihmemies” MacGyver or the Art of re-inventing the wheel

Like many readers I was still a child when MacGyver burst onto our TV screens with tales of action and adventure with some basic physics and chemistry principles mixed in. I always just knew it as MacGyver, in Finnish he is “Miracle-man MacGyver”. Although the re-runs are again on Finnish TV, it looks a bit dated and I wonder if kids really enjoy it in the same way as I and countless others did? Without realizing it at the time, it was the ultimate practical application of science, even if the “problem” at hand was defusing a bomb while dodging laser beams.

In our fieldwork occasional practical problems occur and although not as dramatic as those shown in the TV series, they still need engineering solutions. We call this “MacGyvering”. For example, this year we need to take benthic samples using a small Ponar grab. This is basically a stainless steel grab, which is lowered to the bottom in the open position. On contact with the soft sea bed, it closes and “bites” into the sediment, thus trapping our sample. This is then hauled back up to the boat where the sample is sieved and sorted. More of that in a moment. Although the grab itself is not particularly heavy, even when full, we quickly realized that simply lowering and raising it by hand over the side of the boat could cause back problems, particularly if the site was 20 metres deep. Added to this, to get the best sample we needed to be able to control the grab’s descent so that from a metre or so above the bottom, the user could slowly and carefully lower it to the seafloor. This measure avoids what is known as the “bow-wave effect”. This is caused when water pressure builds in a wave in front of the grab as it rapidly descends. If the grab is allowed to impact the bottom at high speed it will bite deeply but the pressure wave will cause surface sediments, as well as the animals we want to catch to be blown sideways away from the grab. While commercial solutions are of course available, it takes time to budget for, search on the net, select and order them. There had to be another way. Hmmm…. What would MacGyver do?

One of many badly drawn concepts for a pulley system attached to the boat's rails. Photo: Kevin O'Brien.

Our first idea was to build some sort of winch system which could sit on the side of the boat and be fixed in place on the side rails. Some discussion and lots of terrible drawings later we had a starting point. The initial idea was to use two wheelbarrow (kotikärry) wheels complete with inflatable tyres and bearings (laakerit), which would be bolted together and fixed in place on an axle. The grab rope would fit into the groove between the tyres and be gripped there to aid in raising and lowering the grab. This pulley (pylpyrä) mechanism would allow the user to stand inside the boat and be able to operate the system with a straight back. So far, so simple.

The finished pulley system ready for trial. Photo: Kevin O'Brien.

The next problem was figuring out how to to attach the pulley to the side of the boat. We had various ideas on paper but quickly realized that whatever we came up with, we would still need to be able to lift the whole grab over the side of the boat. Luckily, one of our boats has a platform extension on the stern, which is about 10 centimetres above the waterline and to which is attached a diving ladder. The ladder is held in place by two strong bolts. Ok, so now we knew where the winch was going to be and how to attach it. Next step, materials!

After a half day’s shopping in Biltema, we had everything we needed. The initial idea of using two wheels was abandoned. Instead we used a single wheel with the tyre removed and the inner tube cut and glued to fit the concave profile of the metal rim. The frame was simply constructed of wood with some hinges to allow the pulley to extend out over the water. This also allowed the full grab to be brought closer to the back platform where it could be transferred to the awaiting sample box. Ugly as heck, but worked perfectly!

From theory to reality! A Ponar grab sample is retrieved. Photo: Heidi Arponen.

Now to the sampling itself. Depending on the amount of sediment returned in the grab, sieving this material could be quite difficult. Thus, we needed a way to rinse the sample, some sort of shower jet but one which we could vary the power so as not to damage the small and fragile animals contained within. While in Biltema, we found an electric boat bilge pump which runs on 12 volts. With a flow rate of 95 litres per minute it seemed to be tailor-made for our purposes. The pump was fitted with hose and a garden shower head which allows the user to select several different patterns and flow strengths, from stream to a “fine mist”. We rigged the pump to a 12V car battery and installed a switch. When in use the pump was simply dropped over the side of the boat, suspended in the water and switched on. The result was a variable water flow with enough power to aid sieving but not to damage the benthic animals. Result!

Our system for washing benthic samples. Simple but effective. Photo: Kevin O'Brien.

Other projects:

A large part of our work in the VELMU (Vedenalaisen luonnon monimuotoisuuden kartoitusohjelma) programme since 2004 has involved filming and recording the seabed and collecting inventories on what habitats occur along the Finnish coastline, e.g. sediment type, dominant vegetation, etc. Since then our cameras have seen some interesting changes. Our newest state of the art equipment about to come “online”, features LED lights, high definition cameras and lasers, as well as new software allowing us to map the seafloor better than ever before. It wasn’t always like this though. The original cameras were waterproof security cameras protected by a piece of PVC pipe, weighed with a 2 kg lead weight and the camera cable reinforced by taping a rope at metre intervals along its length. Lights, usually a diving torch could be added for deeper sites or during low light conditions. Onboard, live film could be viewed in real time and recorded using a Sony handycam or other digital video recorder (DVR). With the advent of LED lights, with clean white light and low power usage, we could still have diffuse light without too much weight, leading to the form below.

Original SD camera in PVC housing with LED lights and HD sport camera modifications. Photo: Kevin O'Brien.

The lights are powered by a second cable and can be switched on or off at the surface depending on the light conditions near the seabed. The security cameras produce a standard definition (SD) video so this year we added a high definition (HD) sport camera to film also. This gives us live view and SD video as back up, as well as a high definition recording for analysis. This year we had three such dual camera systems. The nicest one though and with the most personality has to be the one “pimped” by our summer workers, which they called the Kuutti Explorer (kuutti is a seal pup).

The Seal PUP Explorer. Photo: Kevin O'Brien.

The cutest camera we ever had! Photo: Kevin O'Brien.




For many aspects of our work, including videoing, diving or bottom sampling, we often need to figure out ex tempore solutions in the field to meet our sometimes demanding work needs. With marine teams covering the marine national parks and the entire Finnish coastline, that is a lot of creative thinking and clever people. In the five years I have worked in Metsähallitus Natural Heritage Services, I have had the opportunity to be involved in creating such solutions and enjoy rising to each new challenge, from an idea to a badly drawn sketch to an actual working gadget in the field. MacGyver would be proud!

Constructing a field laser. Photo: Heidi Arponen.

 

Teksti: Suunnittelija Kevin O'Brien.