WO2010114380A1

WO2010114380A1 - Controllable propeller device of the canister type for a vessel

Info

Publication number: WO2010114380A1
Application number: PCT/NO2009/000133
Authority: WO
Inventors: Kristian Haslum
Original assignee: Marotec A/S
Priority date: 2009-04-03
Filing date: 2009-04-03
Publication date: 2010-10-07

Abstract

Controllable propeller device (1) of the canister type for a vessel wherein the mechanical and hydraulic devices (3) of the propeller device are substantially enclosed in a cylinder container (5) which is sealed against ingress of water, the unit can be pulled into the vessel by a jacking mechanism (7) inside the ship, the cylinder container (5) with the propeller device (1) is pulled into the vessel as a unit.

Description

Controllable propeller device of the canister type for a vessel

The present invention concerns a controllable propeller device of the canister type for a vessel wherein the mechanical and hydraulic devices of the propeller device are substantially enclosed in a cylinder container which is sealed against ingress of water.

Such propeller devices, or thrusters which is the international designation of such propeller devices, are substantially used to keep vessels in position offshore. Some of these are controllable with regard to which direction they are acting - azimuth. Most of the thrusters can control the push the thrust with the rotational speed or the blade pitch.

Normally, thrusters are located underneath the hull of a ship. The result is to obvious disadvantages; the draft of the vessel is increased and the thrusters are difficult to maintenance. Today, two main groups of the thrusters exist. The first main group is the fixed thrusters shown in figures 1 and 2. The second main group is the pull in thrusters which can be pulled into the vessel in order to reduce the draft and for simplified maintenance. The pull in thrusters are complicated mechanical/hydraulic devices wherein much of the mechanical parts are exposed to seawater. For the fixed thrusters the underwater part (which is underneath the hull) can be demounted and keelhauled up to deck of the vessel. However, this is a time consuming operation, such that it is carried out for repair and maintenance and probably not in order to sail into harbour having limitation with regard to depth.

Normally, thrusters will require comprehensive periodic maintenance. This may result in considerable costs related to devices offshore.

Today, another known solution of the fixed thruster is known wherein the fixed thruster is mounted in a canister including all corresponding equipment as shown in figure 4.

An object of the present invention is to provide a controllable propeller device which is located underneath the hull and wherein the advantage of the pull in type is achieved and such avoid the disadvantages of the fixed type of thrusters. Another object of the present invention is that the maintenance advantages of the canister solution is achieved in that most of the equipment is kept dry and that the complete unit can be taken onshore for maintenance.

The objects of the present invention are achieved by a controllable propeller device of the canister type for a vessel wherein the mechanical and hydraulic devices are substantially enclosed in a cylinder container which is sealed against ingress of water, characterized in that the cylinder container including the propeller device can be pulled into the vessel as a unit.

Preferred embodiments of the controllable propeller device is further explained in the claims 2 including 7.

The invention will be explained in the following with reference to the attached drawings, wherein figure 1 and figure 2 depict a controllable propeller device or thruster of a fixed mounted azimuth - thruster type, figure 3 depicts a underwater part of the thruster according to figure 2, figures 4a, 4b, 4c, 4d and 4e show a thruster in a canister unit, figure 5 further depicts the canister unit itself from figure 5 in a disengaged state, and figure 6a, 6b and 6c depict a preferred embodiment of a controllable propeller device according to the present invention.

With reference to figures 1 , 2 and 3 an example of a fixed mounted controllable propeller device which is utilized today is shown.

Figures 4a, 4b, 4c, 4d and 4e further shows an embodiment of this fixed propeller device wherein parts of the propeller device is mounted in a canister or a cylinder container. As previously discussed pull-in propeller devices are known.

The present invention combines in a new and inventive way the advantages and the features of the fixed propeller device mounted in a cylinder container with the pull in propeller device.

The main feature of the solution is that the fixed propeller device of the canister type is prepared for pull-in. The result is that the complete propeller device 1 including cylinder container 5 containing mechanical and hydraulic devices 3, could be pulled into the vessel and that the supply of electric power, control signals and cooling liquid must be supplied via a flexible tube 4 shown in figure 5. The flexible tube 4 is in the shown embodiment routed in a spiral form around the upper narrowed part 6 of the cylinder container 5 or the canister. The flexible tube 4 has an uncoupling mechanism, preferably in the upper end terminating in the hull. A jacking mechanism 7 for elevating/lowering the canister will be provided within the vessel. The canister may further be equipped with a ballast system in order to ease the elevating/lowering process. When the canister is further elevated upwardly from the "top position", it could be lifted completely out of the hull for maintenance. Prior to this the flexible tube will be disconnected in the upper end by means of a coupling here. With the present invention it is achieved in a unique way a controllable propeller device wherein only a small number of the parts are exposed to water, substantially seawater. This will in a large degree contribute to reduce the maintenance costs and extend the lifetime of the propeller device. The propeller device 1 is made for pull-in, i.e. that it can be pulled into the hull of the vessel and thus not be critical with regard to the draught of the vessel. Further, the propeller device 1 could be mounted / demounted in a dry environment inside the ship, which also will contribute to favourable working condition for the staff carrying out this work.

Claims

1. Controllable propeller device (1 ) of the canister type for a vessel wherein the mechanical and hydraulic devices (3) of the propeller device are substantially enclosed in a cylinder container (5) which is sealed against ingress of water, the unit can be pulled into the vessel by a jacking mechanism (7) inside the ship, the cylinder container (5) with the propeller device (1) is pulled into the vessel as a unit, characterized in that the supply conduits of the propeller device in the form of electric power, control signals, cooling liquid etc. are assembled in a flexible tube (4) having path-ways for the supply conduits.

2. Controllable propeller device (1) according to claim 1 , characterized in that flexible tube (4) is routed in a spiral form around an upper narrowed part (6) of the cylinder container (5).

3. Controllable propeller device (1) according to claims 1 or 2, characterized in that the flexible tube (4) is provided with uncoupling mechanism in the upper end which terminates in the hull of the ship.

4. Controllable propeller device (1) according to claim 3, characterized in that unit is releasable by use of the uncoupling mechanism whereby the unit is elevated and can be lifted out of the hull of the ship.

5. Controllable propeller device (1) according to anyone of the previous claims, characterized in that the cylinder container (5) is provided with a ballast system.