ASYMMETRIC BRIDGE

Abstract: An asymmetric bridge (20) of a ship (10) where the main navigation workstation (21) is located aside the center line of the ship on the starboard side of bridge at the starboard end of the bridge. The front bulkhead (15) of the bridge is directed from the main navigation workstation to the port side of the ship (10) in an angle ( alpha ) abaft the beam. The aft bulkhead (16) of the bridge is directed from the main navigation workstation to the port side of the ship (10) in an angle ( beta ) between the direction of center line of the ship. The angle ( alpha ) is preferably 10-15 DEG and the angle ( beta ) 40-45 DEG . The angle ( THETA ) of the field of vision is about 320 DEG seen along the bulkheads of the bridge (20).

Description: ASYMMETRIC BRIDGE BACKGROUND OF THE INVENTION This invention relates to a bridge of a ship and specially to an asymmetric bridge where the main navigation workstation is located aside the center line of the ship on the starboard side or on the port side of bridge. When designing the bridge form for a ship the most important factors to be considered are the overall view required from the inside of the bridge and the field of vision required from each workstation. For safe navigation and manoeuvreing of the ship it is necessary that all objects of interest for the navigation, such as ships, lighthouses etc. can be seen in any direction from inside the wheelhouse. The workstations for navigation and traffic surveillance/manoeuvreing are prescribed in the Det Norske Veritas-regulations. Additionally according to those rules it will be needed also different kind of other workstations such as: - workstations for conning - workstations for route planning - workstations for manual steering - workstations for docking - workstations for performance of additional functions The bridge of the traditional merchant vessel is symmetric. Normally the main navigation workstation is located in the center of the bridge. The simple steering workstations may be added on both sides of the bridge at bridge wings for docking. This same arrangement is still used also on the bridge of the modern passenger ship. In some cases like in the modern icebreakers the main navigation workstations are situated on both wings and a simple steering workstation is in the middle. This arrangement, however, is complicated and takes lots of room because all the systems must be duplicated. To avoid double systems on the bridge the asymmetric bridges have been used. The main navigation workstation is in that case located unsymmetrically on starboard side because of the collision regulations. The vessels shall normally allow sufficient space for safe passing to the vessels coming from starboard side. Especially the modern research vessels have been equipped with asymmetric bridges because a long side wing gives a good visibility towards the stern of the ship. For the same reason also some modern one man bridges for a cargo ship have been asymmetric. However the modern asymmetric bridges have also disadvantages. The asymmetric bridge form considerably limits the view seen from the main navigation workstation. To fulfill the requirements for the field of vision according to the international rules and for example Det Norske Veritas rules for one man bridge regulations the different workstations must be located in the different parts of the bridge. The view from the bridge is also limited by the superstructures, funnels and stairways which limit sight especially aftship. Besides for navigation and manoeuvreing the sight aft and around the ship is also needed when working for example on the work deck aft, on the helideck, by the side doors, on rescue equipment area and with the research equipment, etc. Good aft and around sight makes also possible to control the deck equipment like cranes, winches, research equipment etc. It also reduces the manning at the bridge and adds co¬ operation in different operations even in that amount that the often used aft wheelhouse can be left away. By using the asymmetric bridge design it is possible to gain sight which is superior compared to the present bridge design and makes possible to concentrate the most operations to be controlled by one main workstation on starboard side. The consequences are that the manning on the bridge can be reduced. Due to the good sight at least the following workstations at the bridge can be combined: - workstation for navigation - workstation for traffic surveillance/manoeuvreing - workstation for manual steering - workstation for docking operations - workstation for conning - workstation for performance of additional operations like - crane and winch controls - dynamic positioning control - research equipment control - helideck control - work deck operations control etc. Normally only a secondary docking workstation on the port side is needed for harbour operations and for the special operations. The unobstructed sight has been achieved by placing the main workstation as far as possible away from all obstructing structures like stairways, lift if used, funnel etc. which will be located on the port side corner of the bridge. By this arrangement the blind sector will be minimized. Also by forming the bridge bulkheads in line in the direction of sight so that they widen towards the corner where the obstructions are the excellent sight can be achieved. Also by placing all the extra workstations like workstation for safety operations, for radio, for machinery and for navigation into this blind sector this superior field of sight has been made possible. Best result for the good sight close to the vessel can be achieved by also having at least partly asymmetric deckhouse. SUMMARY OF THE INVENTION According to the invention the bulkheads of the bridge are so directed that from the windows of the main navigation workstation can be seen - to the reverse side of the ship ahead of the front bulkhead of the bridge in an angle abaft the beam, and/or - to the stern and to the aft deck of the ship in the direction that forms an angle between the direction of the center line of the ship. The above and other features and advantages of this invention will become better understood by reference to the detailed description that follows, when considered in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 presents a ship seen from side equipped with an asymmetric bridge according to the invention. FIG. 2 presents a sectional view of the ship according to FIG. 1 seen from top. FIG. 3 presents the ship according to FIG. 1 seen from bow. FIG. 4 presents the ship according to FIG. 1 seen from stern. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT In FIG. 1 is shown a ship 10 seen from side equipped with an asymmetric bridge 20 according to the invention. The main navigation workstation 21 is placed on starboard side into a wing 22 where it is sight to the aft deck 11 and the fore deck 12. The vertical blind sectors 13 and 14 are very small as it can be seen In FIG. 1. In FIG. 2 is shown the ship 10 of FIG. 1 seen from top and the sectional view of the bridge 20. The form of the bridge 20 is asymmetric so that the main navigation workstation 21 is on starboard side in a wing 22. One man can navigate the vessel at the main navigation workstation 21 fulfilling Det Norske Veritas-regulation requirements for one man bridge Wl. The workstation console is normally arranged either for one man or for two men. The workstation 21 console is formed in the way that it is easily possible for the navigator to walk around the console in order to get the best possible sight and to facilitate handling of the navigation equipment. Of course the console can also be located directly against the bulkheads depending on the size and use of the vessel. The forward and aft bulkheads are placed in the angled position so that the angle Φ of the blind sector is minimized in view of the both bulkheads. In FIG. 2 can be seen that the field of vision is not only directed forward and to both sides but also aft. According to IMO's International Regulations for Preventing Collisions at Sea the horizontal field of vision should extend at least over an arc from 22,5° abaft the beam on the side, through forward, to 22,5° abaft the beam on the other side. In FIG. 2 the horizontal field of vision extends an angle τ which is about 30° abaft the beam on the port side. On the starboard side the angle even much bigger . In the ship 10 of FIG. 2 the port side wing 23 of the bridge 20 is equipped with a secondary navigation workstation 24. The field of vision is unobstructed to fore ship, to aft ship and to port side bulwark because all the bulkheads are equipped with windows 18 in order to facilitate easy harbour manoeuvreing. Only the main workstation 21 is normally equipped for normal navigation. This arrangement reduces the number of the navigation equipment and saves costs. On center line of the bridge 20 there is another secondary steering workstation 25 with a sight to fore ship and also aft. This workstation 25 is meant for so called line navigation and it is normally equipped with a steering device and a compass. In the horizontal blind sector 26 of the main navigation workstation 21 the following objects are located: - chart table - radio center - machinery control - office space - safety center etc. This arrangement makes also possible to place the equipment and the space needing illumination as far as possible from the main navigation workstation 21. Typical such spaces are the stairs to the bridge deck, toilet, the lift and the pantry. The funnel 27 is preferably placed outside the wheelhouse 28 in the blind sector. In special cases the whole wheelhouse 28 can be built vice versa like a mirror picture so that the main navigation workstation 21 locates on the port side. All the bulkheads of the bridge 20 in the ship 10 of FIG. 2 are equipped with windows 18 except the bulkhead 29 in the blind sector where the windows are optional. Therefore the horizontal view angle Σ of the field of vision can be up to about 345°, almost around the horizon. The blind sector angle Φ is only about 15-20°. In FIG. 3 can be seen that on starboard side the navigator can see water very close to the ship from the main navigation workstation 21. The vertical blind sector 30 is not very large. Of course the navigator can walk around the main navigation workstation 21 to have even better view to the ship side for instance when docking is taking place. On port side the vertical blind sector is under the sector line 31 in FIG 2 and FIG. 3 when looking from the main navigation workstation 21 through the port side window of the bridge. According to the invention the field of vision is so large on the bridge 20 because the front bulkhead 15 of the bridge 20 is directed in an angle α of about 12° abaft the beam on the port side. Also the angle β between the aft bulkhead 16 of the bridge 20 and the direction of center line of the ship is about 42° on the starboard side. When the navigator looks out of the window 18 to the port side along the front bulkhead 15 of the bridge 20 only the deck of the lower deckhouse deck 17 limits the vertical field of vision. The sector line 32 illustrates the vertical border of the field of vision in FIG. 3 and the horizontal border of the field of vision in FIG. 2. If the ship 10 is not provided with the overhanging lower deckhouse deck 17 or the deck 17 is designed to be more inclined only the fore deck 12 of ship 10 and the sector line 33 limits the vertical border of the field of vision. In that case on port side there is only a small blind sector 34. In FIG. 4 is shown the ship 10 seen from stern. The vertical field of vision on the sides of the ship extends very close to the ship. The sector line 35, seen in FIG. 1 and in FIG. 4, is directed along the aft bulkhead 16 of the bridge 20. As it can be seen in FIG. 1 the stern deck 11 is very well in the field of vision. According to the invention a large field of vision around the ship 10 is achieved from the main navigation workstation 21 so that there is no need for the navigator to move anywhere from his place.

Claims: CLAIMS 1. An asymmetric bridge (20) of a ship (10) where the main navigation workstation (21) is located aside the center line of the ship on the starboard side or on the port side of bridge, characterized in that the bulkheads (15, 16) of the bridge (20) are so directed that from the windows (18) of the main navigation workstation (21) can be seen - to the reverse side of the ship (10) ahead of the front bulkhead (15) of the bridge in an angle (α) abaft the beam, and/or - to the stern and to the aft deck (11) of the ship (10) in the direction that forms an angle (β) between the direction of the center line of the ship. 2. An asymmetric bridge (20) according to the claim 1, characterized in that the main navigation workstation (21) is located at the starboard end of the bridge (20) and the front bulkhead (15) of the bridge is directed from the main navigation workstation to the port side of the ship (10) in an angle (α) abaft the beam. 3. An asymmetric bridge (20) according to the claim 1 or 2, characterized in that the main navigation workstation (21) is located at the starboard end of the bridge (20) and the aft bulkhead (16) c>f the bridge or the starboard side bulkhead of the bridge is directed from the main navigation workstation to the port side of the ship (10) in the direction that forms an angle (β) between the direction of center line of the ship. 4. An asymmetric bridge (20) according to the claim 1, 2 or 3, characterized in that the angle (a) between the front bulkhead (15) of the bridge and the beam of the ship (10) is 10-15°. 5. An asymmetric bridge (20) according to any of the claims 1-4, characterized in that the angle (β) between the aft bulkhead (16) or the starboard side bulkhead of the bridge and the direction of center line of the ship (10) is 40- 45°. 6. An asymmetric bridge (20) according to any of the claims 1-5, characterized in that the front bulkhead (15) of the bridge (20) and the aft bulkhead (16) of the bridge are directed so that from the main navigation workstation (21) can be seen in the direction of those bulkheads. 7. An asymmetric bridge (20) according to any of the claims 1-6, characterized in that the angle (θ) of the field of vision seen from the main navigation workstation (21) along the bulkheads of the bridge (20) is up to about 320-330°. 8. An asymmetric bridge (20) according to any of the claims 1-7, characterized in that the angle (Σ) of the field of vision seen from the main navigation workstation (21) on the bridge (20) is up to about 330-345°. 9. An asymmetric bridge (20) according to any of the claims 1-8, characterized in that the blind sector angle (Φ) of the field of vision seen from the main navigation workstation (21) on the bridge (20) is about 15-20°.

Inventors: ERONEN HARRI, HAGELSTAM LENNART, HARJULA ARJO, ERONEN, HARRI, HAGELSTAM, LENNART, HARJULA, ARJO
Applicants: ERONEN HARRI, HAGELSTAM LENNART, HARJULA ARJO, MERENKULKUHALLITUS, ERONEN, HARRI, HAGELSTAM, LENNART, HARJULA, ARJO
Application year: 1992
Main classification: B63B15
IPC codes: B63B15, B63B29, B63B35, B63B49