A watercraft steering system includes a reverse reduction transmission and an obstacle detector. The reverse reduction transmission is configured to convert power from a main engine into an output for causing a watercraft to make forward travel, neutral, or reverse travel, so as to control navigation of the watercraft. The obstacle detector is disposed at a hull of the watercraft and is configured to detect an obstacle. The watercraft steering system is configured to, based on a location of the obstacle with respect to the hull, a travel direction of the watercraft, a travel speed of the watercraft, and a distance between the hull and the obstacle, select from among the forward travel, the neutral, and the reverse travel, and maintain the travel speed or change the travel speed.

A method of operating a marine propulsion system (1) in a trolling mode. The marine propulsion system (1) comprises at least one propeller shaft (6) which can be driven by an engine (2), via a pressure operated forward clutch (4), in a forward direction or, via a pressure operated reverse clutch (5), in a reverse direction. A forward pressure is applied to engage the forward clutch (4) to a certain extent and, at the same time, a reverse pressure is applied to engage the reverse clutch (5) to a certain extent. A value of the forward pressure is different from a value of the reverse pressure so that the propeller shaft (6) is caused to rotate in a desired rotational direction. A control unit with mechanism to operate the marine propulsion system according to the method and a marine propulsion system with such a control unit are also disclosed.

The invention relates to a manoeuvrable trailing dredging vessel comprising; a vessel propulsion member coupled with a propulsion shaft provided with a single gear for driving the propulsion member, a drive system having a central drive shaft coupled with the vessel propulsion member for providing power to the vessel propulsion member, a transmission device having at least a trailing transmission shaft provided with a trailing pinion and a sailing transmission shaft provided with a sailing pinion, wherein the central drive shaft is coupled with the single gear of the propulsion shaft through one of the trailing transmission shaft and the sailing transmission shaft.

The invention relates to a manoeuvrable trailing dredging vessel comprising; a vessel propulsion member coupled with a propulsion shaft provided with a single gear for driving the propulsion member, a drive system having a central drive shaft coupled with the vessel propulsion member for providing power to the vessel propulsion member, a transmission device having at least a trailing transmission shaft provided with a trailing pinion and a sailing transmission shaft provided with a sailing pinion,
wherein the central drive shaft is coupled with the single gear of the propulsion shaft through one of the trailing transmission shaft and the sailing transmission shaft.