Mike Shrimpton has won our intermediate category.

Fed up with hand-loading timber into a biomass chipper, Dorset farmer Mike Shrimpton sought some mechanical assistance.

First on his shopping list was a Kilworth pto-driven chipper, followed by a Botex forestry crane to load it with and a 6t AS Marston dump trailer to collect the spoils.

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The challenge then was finding a way of meshing this trio into single rig that was compact and manoeuvrable enough to navigate around the farm’s 120ha of heath and woodland.

To kick things off, he set about joining the crane to the chipper, using an A-frame that attaches to the original three-point linkage mounting points.

Extra bracing was incorporated to make sure there was no risk of warping when it was working at full capacity.

Next, he needed a chassis on which to mount the chipper/crane assembly and tow the trailer behind.

Due to the terrain it was going to be tackling, this had to be both compact and lightweight, so there was no room for over-engineering.

Aircraft inspiration

He therefore opted to build it out of a single piece of 180mm box-section, internally braced with 155mm box in the areas which would be subject to the highest forces – an idea he borrowed from the wing spar of a Supermarine Spitfire.

The chipper and crane attach to this using three-point linkage brackets at the front and a third bracket at the rear, while the dumper connects via a double pivot.

To make sure it turns suitably tight, Mike shortened the drawbar to a stub and fitted hydraulic rams on each side to give it forced steering.

This setup gave the trailer a suitably agile 40deg turning ability. However, when pushed to full lock the outfit could become unstable.

He solved the problem by moving the trailer axle forward so that it sits under the middle of the load.

Finally, road lights, hydraulic braking and tipping pipes were all extended to link up with his reverse drive Valtra M150 on the front.