Sled (aka) Slide and Stone Boats

Draught horses have to learn to pull.  One way used is to  start with an old truck wheel, then gradually progress to increasing weight and size of sleds.

Three progressions: truck tyre, small standing sled and two seater sled
Working with the small standing training sled
This two seater can carry a third person standing behind
Much heavier, this two horse sled can comfortably carry four passengers, two sitting and two standing behind