Anti-drift bumpers
A wheel fixed to one or to both drives and idle units prevents the vessel from drifting (as per picture 1).
Anti-drift steering idle unit (manual or automatic)
Steering idle unit can be manually (as per picture 3 image Nr. 3) or automatically (as per picture 3 image Nr. 4) managed by means of an hydraulic jack controlled by tactile inductive or by laser sensor.