Not easy. This was a problem my high school math tutor, a glaciologist [0],[1] discussed with me one evening doing some applied math.

From memory, using a tug to pull an iceberg from Antartica to the Australian mainland would be difficult because of the forces involved. As the tug would try to pull the iceberg, the iceberg itself is acted on by other forces (gravity, currents). The tug pulling the iceberg, connected by a cable would be acted on by the forces applied by the iceberg resulting in the berg and tug rotating in circles around each other. [2] Adding another tug has similar problems.

The idea isn't stupid, it's just the physics get in the way of achieving a result.

[0] 1970 - 2003 http://www.antarctica.gov.au/news/2003/antarctic-ice-man-and...

[1] 2003 - 2016 https://rmdb.research.utas.edu.au/public/rmdb/q/indiv_detail...

[2] If memory serves me, Jo used 'moments of inertia' to describe this problem ~ https://en.wikipedia.org/wiki/List_of_moments_of_inertia