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Spider reaches out to defeat the weed menaceThe Problem Like a bush regenerator's fingernails, cliffs and quarries also accumulate pockets of dirt in nooks and crevices, and anywhere that happens you can be sure the weed seeds will somehow find their way there. And so they did on the cliff face at Cornelian Bay, Hobart, flourishing and multiplying in the way that weeds do best until there was a pretty good coverage of Cotoneaster, Boneseed, African Boxthorn and Red Valerian, safely inaccessible to those who would dearly love to see them blitzed. But how to achieve this without losing anyone over the edge or damaging the infrastructure? 
This was the question posed to Regnans enviro contracting when the Cornelian Bay Bushcare Group were successful in gaining an Envirofund grant to help them with several projects, one of them being the clean-up of the cliff face from the beach at the head of the bay to the seaward end of the point, a distance of about 550m and a height of around 10m. In June 2006, we were asked to research the 'best' method of attack to clear the cliff face of the above weeds, spray the weeds on the top of the cliff on the danger side of the walking track, and remove the cut debris from the site without it floating away on the incoming tide. Yes, the stony base of the cliff is covered almost right to the edge of the cliff except at the spring tides which only happen at fortnightly intervals. Only then does a wide enough swathe of the 'beach' become uncovered sufficiently for work to be carried out from the base of the cliff. So we did a bit of brainstorming –
But each of these had disadvantages:
A long-legged approach Enter the spider, or rather, one of its mechanical cousins. While shopping at the Kingston Centre, I saw a compact EWP (elevated work platform) sitting on big, balloony tyres and it suddenly came to me that maybe it could negotiate the rocky platform and shingle scree at the base of the cliff and then we could do the work from the safety of a basket. A quick call to the hire company and a site visit brought the answer - No, that machine probably wouldn't do the job as it required to be on level ground, was about seven tons and would probably damage the foreshore structure. But wait a minute… there was another EWP with a potential 17m lift that ran on tracks, was around 2.5tons, only 1200mm wide but with legs that could be individually swung out and manoeuvred to create a level and stable work platform; the Omme 1750 RD Lift from Denmark - colloquially known as the Spiderlift, for obvious reasons when you see it. What a great little machine. It looked as though it could be the answer to all the criteria we needed to fulfill and so we had it go through its paces at the hire depot. It confirmed that all the different aspects of the job could, in theory, be fulfilled with the one machine in much greater safety and less damaging than any of the other methods. We could even utilise the spider to remove the cut debris, saving ourselves a lot of manhandling, though we weren't exactly sure how just then. Now we just had to convince the clients that this was the way to go, get ourselves certified (some thought that was done long ago, ha, ha) to use the machine and get on with the job. Putting the theory into practice 
Not quite so simple … a peculiarity of the Hobart tides meant that for weeks we couldn't use the low tides we needed because they always took place well outside of work hours, usually in darkness. When they were predicted to come at the right time of the day, in October, it turned out that the machine was already booked out on the days we needed it and then for a further solid two months, so we missed all the possible low tides until after Christmas. And the next good tide was New Years Day, so it wasn't until mid January that we finally got started on a job that was meant to be finished by November. But at last the day came and we trundled the machine down the beach and around the corner at the base of the cliff, and here we nearly came to grief before we'd even started when the machine slithered over the slippery rock shelf and tipped into a boggy bit. Getting it out, thanks to the expertise of Sherrin Hire's operator who was minding us for a while to make sure we were competent in its use, was a valuable lesson in what might happen and some useful methods for getting out of tricky situations (which we had to use in earnest a couple more times when the sand surface of the beach suddenly gave way). Somewhat chastened, we continued, with the machine lurching over the uneven ground in what looked a most alarming manner, but it took it all in its stride and by the time we'd rounded the point we were feeling much more competent at handling the beast and reading the ground ahead. 
Now came the actual business part of the exercise – removing the weeds – and happily this went really well. The manoeuvrability of the machine to get the operator right to the spot in relative comfort was delightful. The frequent moves required gave us plenty of practice in setting up level and becoming familiar with all the controls and after a couple of hours we were deemed fit enough to go it alone. The window of opportunity on each usable day was only 4.5hrs time actually on the beach, allowing for a margin of error to get the machine safely back to dry land so the work was very concentrated and preparation a pretty important part of it all. Just driving down to the point took nearly an hour one way although this time decreased a little as we worked back towards the start. Additional time on the day was also required to set up and pack down. The Lift was left on site near the beach for consecutive day's work. Another two days went by and we were really getting into the swing of things until disaster struck just as we were driving out at the end of the third day's session, which coincided with the end of the working day – about five thirty. One of the rather worn tracks (they were due for replacement on completion of this job) got hooked under a lip on a rock ledge which threw it off its guides and jammed it against the body of the machine. With the tide now rising, we sprang into action to use everything at our disposal to try and get it back on line but it was just too tightly jammed and we had to make an emergency call to the hire company to send someone over. This they did - fortunately, the engineer wasn't already halfway to the lakes, fishing - and he was with us in about fifteen/twenty minutes. With his arrival and a good assortment of tools and expertise, it was still no easy task to get the track back on but it was finally accomplished just about the time the water was lapping around the engineer’s toolbox. Thanks to our margin of error we got back to solid ground home and dry. Now we just had another delay while waiting for the new tracks to arrive, but the final day, a month later, went without hitch and the job was completed without furthur incident. 
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