Directional Drill

Directional Mole - this is an expensive tool, so no-one uses it much. With a basic 'mole' you set it off in a straight line aimed at its destination, hoping it doesn't veer off on its way. With a directional mole you have some control over its route - you get a depth reading from a detector from which you decide if and when to change its trajectory. This may be ideal if you want to go deep below something and come up again - like a river for example - but you still need to be lucky with rocks.

B4RN have used a directional drill under the Lune - that needed Environmental Agency approval

(And there is a recent B4RN story that someone has punctured a canal by not going deep enough)

Pictures with kind permission of Casterton Video lifted from B4RN via Google

The same type of machine appears in an American video at https://www.youtube.com/watch?v=sMTQJjqF3lg