Abstract: A pitch angle indicator system indicates a pitch angle of blades of a propeller of a marine propulsion unit. A mechanical link couples at least one of the blades to a first end of a first rod. An indicator is coupled to a second end of the first rod. The mechanical link is configured to convert a change in the pitch angle into a rotation of the first rod about its longitudinal axis. The indicator is configured to provide an indication of the amount of rotation of the first rod about the longitudinal axis.

Abstract: A method of and an arrangement for improving the lubrication system of a propulsion device of a marine vessel are specifically applicable in removing water from the lubrication oil of various types of thrusters. An inert gas is arranged from an inert gas source to flow through a gas cavity in the lubrication system for flushing moist gas from the cavity.

Abstract: A pitch angle indicator system indicates a pitch angle of blades of a propeller of a marine propulsion unit. A mechanical link couples at least one of the blades to a first end of a first rod. An indicator is coupled to a second end of the first rod. The mechanical link is configured to convert a change in the pitch angle into a rotation of the first rod about its longitudinal axis. The indicator is configured to provide an indication of the amount of rotation of the first rod about the longitudinal axis.

Abstract: Disclosed is a method for maintenance of a ship propeller including the steps of: placing a flexible habitat having an open upper end over an uppermost blade and a portion of the propeller hub, and establishing a gas seal between the upper end of the habitat and the blade to close the habitat at its upper end. After fixing the lower end of the habitat relatively to the propeller, compressed gas is preferably introduced into the habitat to displace the water in the habitat. The apparatus for maintenance of a ship propeller under water comprises a flexible habitat with an open upper end. The habitat has a gas seal adapted to cooperate with a propeller blade surface to establish a gas seal to close the habitat at its upper end and fixing means adapted to fix the open lower end of the habitat relatively to the propeller. A means for introducing compressed gas into the habitat is provided.

Abstract: A method of and an arrangement for improving the lubrication system of a propulsion device of a marine vessel are specifically applicable in removing water from the lubrication oil of various types of thrusters. An inert gas is arranged from an inert gas source to flow through a gas cavity in the lubrication system for flushing moist gas from the cavity.

Abstract: Disclosed is a method for maintenance of a ship propeller including the steps of: placing a flexible habitat having an open upper end over an uppermost blade and a portion of the propeller hub, and establishing a gas seal between the upper end of the habitat and the blade to close the habitat at its upper end. After fixing the lower end of the habitat relatively to the propeller, compressed gas is preferably introduced into the habitat to displace the water in the habitat. The apparatus for maintenance of a ship propeller under water comprises a flexible habitat with an open upper end. The habitat has a gas seal adapted to cooperate with a propeller blade surface to establish a gas seal to close the habitat at its upper end and fixing means adapted to fix the open lower end of the habitat relatively to the propeller. A means for introducing compressed gas into the habitat is provided.