Ah yes. I was trying to be too clever.
How do you steer them is something I have often wondered.
The percussive moles such as the grundomat need a launch and receive pits. These pits need to be to quite large as the gundomat needs to be level to launch we are talking hiring a digger size. The only reason to use one would be under an expensive surface. The other problem with the grundomats is that the percussive power has to disapate somewhere and depending on ground conditions this can be upwards causing the expensive suface to crack ( I actually lifted part of the Donington Race circuit on a job with a grundomat we launched at a depth of 6 ft.)
In grass you may find it better and cheaper with a tractor mounted mole plough or a ditchwytch. We found it cheaper to use drainage contractors than hiring stuff yourself.
On the Grundomat we used you don't steer you just launch in a straight line but they can be deflected by hard rocks etc, the Gas board had steerable ones but even they managed to pop one up in the middle of the A38
when soil nailing a railway embankment one of our contractors accidently put a soil nail though a 90' angle and was peeping through the track (aka between the railway sleepers) not good. Not sure what the outcome of the investigation was though...
Mostly they're trouble free though.
||Would a tractor mounted mole suffice? (Not much help if you don't have a tractor)|
||I was told one by someone who'd operated one that they'd once managed to puncture the sewer from a country house. Once the mole punched through the side of the sewer, it raced off up it. How they knew something had gone wrong.|
||On the Grundomat we used you don't steer you just launch in a straight line...|