Guide to Bridge Design  

  The Houston Pilots have written this article in an effort to assist ship owners, builders and naval architects in the design and layout of ship bridges.  It is intended to be a guide for avoiding common mistakes and as a checklist to remind the parties involved of areas they might have overlooked. 

In order to evaluate the worth of recommendations it is important to know the background and interest of the party offering the advice.  This paper has been a group effort with contributions from many members of the association.  A draft version has circulated among the pilots and members of the Houston maritime community for more than a year. Ships come to Houston from all over the world, are designed for a wide variety of trades, and range in size from coasters to over 100,000 dwt.  We supply pilots for 16,000 transits annually.  The 80 members of the Houston Pilots generally have 10-20 years experience in maritime service before being invited to join the association.  Within the membership we have representatives from every type of seagoing and inland marine background.  We have members who are graduates of a wide variety of state and national maritime academies as well as members who have come up “through the hawsepipe”.  As former seagoing officers we are knowledgeable about what works and what doesn’t work at sea. We have built on that knowledge base with experience about what works and what doesn’t work in a congested, restricted waterway.  A typical ship’s officer may work on 20 to 100 ships in his or her career.  As pilots we have the privilege of working on 200 vessels each year.  We have daily opportunities to compare and contrast a broad sample of the world’s merchant fleet.

The design of a “perfect” bridge that will make all pilots and watch standers comfortable in all situations and all ports is probably not possible, but there are some things we can all agree on.  It can be safely said that the more open and panoramic the view, the easier it will be for all parties to do their jobs.  A pilot will often need to stand or sit quietly in one position and be able to check the rate of swing of the ship, its alignment with the channel, the position of an oncoming vessel, the spread of the next set of ranges (leading lights), the proper execution of the last rudder order and a host of other items, all more or less simultaneously.  The objects he or she must observe are spread over a wide area.  Having to move back and forth to various positions to do this makes it much more difficult to get a “feel” for all the elements in a situation and much less likely that mistakes will be detected early and corrected quickly.

When we think of the ideal bridge we should be careful what we picture in our mind’s eye.  Are we imagining a sparkling sea with a cloudless sunny sky and a clear horizon all around?  I hope there are a large number of days like that in your vessel’s future, but we should be designing the bridge for those dark nights with rain and lightning all around; nights where a barge suddenly appears out of the rain in a narrow channel with shoals on one side and docks on the other.  How far do you have to run to look in the radar?  Can you blow the whistle and still use the radio?  Can you see what the helmsman is doing from the radar station?  Do you have to get down on your knees to see the face of the VHF to change channels?  Can the pilot and captain pass without knocking each other down?  Are those lights that suddenly appear in the starboard window another vessel or are they the lights of the first vessel reflected on the vertical surface of a window that should have been canted outward?  In those situations, a few extra dollars and a little foresight can perhaps save lives and millions of dollars of damage.

I.  Bridge Layout

The person responsible for laying out the bridge should always have in mind where the person who will be navigating the ship will situate him/herself, the conning station.  This will be different positions for different situations at sea or in port.

In general, but never always, the conning station for a pilot will be slightly to port of the center window.  In a channel, most traffic will be met port to port so a pilot generally favors the port side of the bridge.    Equipment necessary to the pilot should be located slightly to port when possible.  In contrast, equipment and facilities intended for use by underway watchstanders at sea should be concentrated on the starboard side.  While keeping watch in all directions is important, there is a slight tendency to favor the starboard side at sea since vessels appearing on that side usually have the right of way and your vessel will be expected to take action to avoid them in a close situation.  As bridge designers we should keep this in mind when we lay out positions for radios, intercoms, logbook stations, chart tables, light panels, etc.  Sometimes bridge space is at a premium.  Following these guidelines has the benefit of allowing bridge personnel to do their jobs without getting in each other’s way. 

The exception to pilots favoring the port side is bridge forward designs.  When maneuvering in restricted waters on these ships it is necessary for the pilot to take a position in line with the foremast (or often in line with a wire stretched down to the mast) in order to have a true sense of where the vessel is headed.  In a bridge aft design the foremast is 100-200 meters away it is not a problem if the conning station is off center by a windowpane or two.  If the foremast is only 10-20 meters away the same position is almost worthless due to parallax error.

Just like there can be no perfect kitchen because there are so many chefs, there can be no perfect “pilot center” on the bridge because there are so many different pilots and ports.  That doesn’t mean there can’t be guidelines for bridge design just like there are guidelines for kitchen design.  In kitchens there is a triangle between sink, stove, and refrigerator that designers recommend be as small as possible.  There are many possible arrangements, but this essential triangle must be kept in mind.  For pilots the triangle is the window, the radar and (recently) the chart display.  Ideally these items will be grouped together within a few steps of each other.  Other items like the VHF radio, whistle, searchlight controls and a windowsill/counter for loose items should be located within the triangle.  Things that need to be seen, like the rudder angle indicator, the engine telegraph, and the gyro repeater, must be visible from within the triangle.

Something we have never seen, but think is a good idea, would be a small portable display console that could be set up on the window sill or wherever the pilot (or any watchstander) needs it.  Our idea was something the size of a tissue box with a digital course readout, swing meter, rudder angle indicator, and rpm dial.

Special note on bridge consoles

We are seeing more and more ships with horseshoe shaped bridge consoles.  We recognize it as an attempt to modernize the wheelhouse, but find that in practice the concept is poorly implemented.  The consoles appear to have been purchased from a catalog and plopped in the middle of a bridge with little effort to integrate them into the overall bridge layout or the way mariners operate when making an inland transit.  We very strongly recommend that the consoles NOT be placed directly against the forward bulkhead of the bridge. This placement forces the conning officer to stand several meters back from the windows and is extremely undesirable. (See more on this issue below).

One theory for the generally poor integration of consoles into the bridge layout is that the design studies are conducted in simulators.  In many computer simulators, each window is an individual piece of the whole display and one must step back to look at all the frames to get a full picture.  In reality, the most complete view is obtained by standing directly in the window with one's face close to the glass.  Faced with an enclosed console, pilots have two choices: they can take position in front of the windows and be removed from the other sources of information needed for their jobs; or they can move behind the console and put a bank of lights, window frames and displays between themselves and the outside situation.

These consoles are usually offered as a “package” by the shipyard and are a convenient way to deal with the challenge of integrating the various pieces of equipment. All the gear is sold by a single manufacturer in grouped units with the radar, gyro, AIS, ECDIS, autopilot, etc connected together.  This is not a problem.  The problem arises when the conning officer must circumnavigate an unbroken mass of equipment to get from the window to the radar or a radio.  Since the equipment is constructed in several individual units it is always possible to leave an opening between units to provide direct access to all areas of the bridge.  Such an opening at the top of the “U”, close to the center of the console is ideal.

Another problem with prefabricated consoles is that they are seldom designed for the real world.  The surfaces are slanted, surfaced in glossy enamel, and covered with switches and displays.  Within the console there is often no flat, unobstructed surface to rest handheld radios, binoculars, shipping schedules, or DGPS laptops.  In the real world ships pitch and roll and mariners drink coffee to stay awake long, late hours.  Give us a secure place for a coffee cup and our binoculars.

Our suggestion is to avoid "U" shaped consoles that are only open to the rear.  Equipment can and should be grouped in an efficient manner, but not in such a way that direct access to the windows or to a radar is restricted. The pilot should be able to get what he or she needs to do their job without obstacles.

 CHECKLIST

1.      There should be an unobstructed view forward from conning position.  This should be a given, but sadly it is not.  Whenever possible, bridge windows should be above the height of deck cranes and other obstacles.  It is not only the pilot or conning officer that needs a clear view forward.  It is a common occurrence that the helmsman’s station will be directly aft of a large crane.  It is useful and desirable for the helmsman to use visual references to assist in steering even when steering by compass.  He will be much less likely to “chase the compass” or commit other common mistakes if he can glance up occasionally to check his own performance.

2.      Visibility on many cargo ships is shamefully poor.  Attention is called to 33 CFR 164.15 which deals with visibility from the conning station/bridge.  At present, this rule is not being enforced.  As we all know, all it takes is an accident where visibility is considered a significant factor for this to rise to the surface of the enforcement effort.  The most important visibility line for the majority of navigating and maneuvering tasks is the horizon.  Structures that intersect the line of sight from the bridge to the horizon should be avoided.  Locate boom cradles so that the booms are not resting horizontally in this critical area.  Avoid attaching winches and other equipment to booms at the horizon level.

3.      Do not.  Do not.  Please, do not locate the crane for the last hatch AFT of the hatch unless the bridge windows are higher than the crane.  A crane in this position will block a significant area dead ahead of the bridge.  The conning officer standing to the left or right of this obstacle will not be able to see the opposite side of the ship.

4.      Ships should have open bridge wings for docking.  The usefulness of being able to sense the elements working on the ship, to be able to lean over the rail to judge speed and dock closure, to be able to look down the side of the ship and out in all directions without changing position cannot be overstated.  Even a small 2 meter roofed wing, open on the sides, is preferable to a completely enclosed wing.

5.      There should be an unobstructed view astern from bridge wing for backing to a berth.  Some ships have lifeboats or other obstacles directly astern of the edge of the bridge wing.  This should be avoided.  In our pilotage it is sometimes necessary to back a ship over a mile from the closest turning basin to her berth.  Imagine the pilot, standing back by the stack, shouting orders over the noise of the ventilators to the captain, who is standing halfway to the bridge wing.  The captain, in turn, passes the order via radio or by shouting to the mate at the controls.  Neither the pilot nor the captain have a way to check for the correct execution of the order.  It is a disaster waiting to happen.

6.      If it is necessary to mount a searchlight or floodlight near the corner of the bridge wing it should be located well above or well below the height of eye of the personnel docking the ship from the bridge wing.  The captain and pilot need to observe and compare many things at once during a dock approach.  Every time they have to shift position to see something, their sense of speed, swing and closure are briefly lost until they can stand still and pick the thread up again.  We cannot begin to tell you how irritating it is to have a large inert object in your field of view every time you turn your head.  The rule of thumb should be never to weld a large object in a position where you, as a polite person wishing to be unobtrusive, would not stand while the pilot and captain are engaged in docking the ship

7.      There should be a 120 cm (48”) minimum walkway behind the windows extending the width of the bridge.  This provides enough room for two people to pass each other comfortably or enough room for a pilot chair with a person sitting in the chair. 

8.      There should be a level, 16” windowsill about waist high inside the windows to allow placement of portable computer equipment, radios, notebooks, binoculars, coffee cups and the assorted other gear required to be on hand while underway.

9.      The ship should have a 110-120 volt ac electrical connection located on the forward bridge bulkhead for portable DGPS connection, preferably in the immediate vicinity of the required “pilot plug”.

10.  The helm should be located where the quartermaster has a clear view forward but slightly back from the windows so the captain and pilot have access to the center window without having to look around or over the helmsman.  This is especially important on bridge forward designs. 

11.   We have seen several new ships with the windows extending from the wheelhouse in a bay window or “bubble” style.  We recognize the effort as an attempt to improve visibility, but members who have sat in on ship design panels generally recommend that the builder save his money.  Because of the extra framing and the angles, the bubble actually reduces the field of view unless one is standing in the middle of it.  Standing in the bubble results in one of two problems:  (1) the navigation equipment is not in the bubble and the pilot is there alone, isolated from the navigation equipment, or (2) all the equipment is up in the bubble and he/she cannot get close to the windows.  In practice, normal windows in a straight line are more than adequate for views abeam.  When one needs to see directly abeam, close to the ship, and back near the wheelhouse (the only area of visibility improved by the bubble) it is always in a situation where the quarter needs to be watched as well.  The interested parties will be out on the bridge wing anyway. 

II. Windows

1.      There should be an odd number of forward windows so there is a center window.  If possible, the center window should be at least two meters wide. 

2.      Windows should be large and have direct access not blocked by consoles, tables or other equipment.  In order to have the capability of tracking multiple elements of a navigational situation simultaneously it is absolutely necessary to have the widest possible view.  This can only be accomplished by putting one’s nose inches from the window.  This is where you want the captain or pilot in a tight situation.  The further a person has to stand back from the window the narrower the field of view will be.  Window framing becomes blind spots.

3.      If there is one piece of equipment that may be exempt from the rule of no equipment blocking the windows it would be the radar.  If it will be placed up against the forward bulkhead a good arrangement is a wide window, 2 m or more, with the radar not in the middle but on the left or right side leaving the rest of the window open for an ample conning station. 

4.      The windows should be inclined outward at a slight angle so that lights are not reflected on the inside surface in such a way that would cause confusion to watchstanders.  This applies to all the windows on the bridge, not only to the forward windows.

5.      The bottom of the window should be approximately 90-100 cm (36-40”) high and the top of the window should be approximately 200-210 cm (79-83”) high.  Also see I.8 above (window sills).

6.      Windows should be wide and spaced closely together with a minimum of framing so that a person standing back from the windows has as close to an unobstructed panorama as possible.  We see ships now with all bridge windows two meters or more in width and 7-8 cm framing. 

7.      Window wipers should not be skimped on.  The best we have seen feature a vertical wiper mounted on tracks.  The wiper slides back and forth cleaning the entire field of view.  Wipers should rest at the edge or bottom of the window when not in use; definitely not in the middle of the window.  Centrifugal clearview devices take a good window and make it unusable.  Maybe it’s the perfect thing for Antarctica, but we would spend our money on heated windows and good wipers.

8.      Ships often arrive at the seabuoy with windows crusted with salt from a long ocean passage.  Sometimes we see windows that are almost opaque with hard water deposits on the outside.  An easily accessible walkway should be provided outside the forward windows to allow crewmembers to safely clean windows from the outside.

9.      If a water washdown system for the windows is provided, an inexpensive enhancement is a compressed air connection that allows the water to be followed by a blast of air that augments the force of the water spray and blows the windows clean.  It also empties the water pipe which prevents rust streaks on the windows.

10.  At least one window should be provided with a view astern to allow for easily checking ranges astern of the ship.

11.  A substantial visor over the window is useful in protecting the window surface from rain and shielding the inside of the bridge from the glare of the sun.

12.  The windows should be clear glass, free of any reflective film.  Plexiglas scratches and gets ugly after extended use.  Reflective film is nice during the day, but at night you want all the light coming through that window you can get in order to keep a proper watch. 

III.       Bridge Equipment

1.      The rudder angle indicator should be mounted so it can be easily seen from ALL angles.  An indicator mounted flat against the forward bulkhead is very common and should not be acceptable.  It can only be seen from a limited area.  A rudder indicator should not be mounted directly behind or above the principal conning station, but rather in a place where it can be easily seen from the conning station without the conning officer having to twist around to check the rudder position.  It frequently happens in the course of a transit that the quartermaster puts the rudder port instead of starboard or vice versa.  If not corrected immediately such a minor mistake can have disastrous consequences.  It is a safety item for the conning officer to check that quartermaster actually put the rudder as ordered.  Making it easy to do so will help ensure that it gets done.

2.      Since the pilot’s usual conning station is slightly to port it doesn’t make sense to place equipment that will be used mostly or exclusively by the ship’s crew in this area.  Try to put the internal phone system, logbook station, light switches, engine order telegraph, etc to starboard of the centerline.  It is difficult for a pilot to navigate at night with the mate standing next to him, waving a flashlight, writing in his logbook and calling around the ship to conduct ship’s business.

3.      The steering gyro should be equipped with an inner caliper or other mechanism that allows the helmsman to detect changes in heading of less than one degree.  The best steering gyros show 1/8 or 1/10 degree changes.  A swing meter that measures rate of heading change is also useful to both pilot and helmsman.

4.      There should be a gyro repeater visible from conning station, u/w watch station, and from both radar positions.  Sometimes gyro information is available on the radar screen where it is very useful.  A lighted digital gyro readout above the windows on the forward bulkhead is a good option.

5.      The whistle will be seldom used except in close call situations or fog (or both).  The controls should be placed in several convenient locations: centerline forward bulkhead, radar station, and both bridge wings.  They should be labeled with big letters and easy to find at night.

6.      10 cm radar should be on the starboard side for use of u/w watch standers.  It has longer range and is generally designed for use at sea.  The 3 cm radar is designed to be used in port.  The short wavelength allows targets to be sharply defined.  It is possible to judge the relative size of targets making it easier to distinguish which target is the ship, the buoy, the tug etc.  It should be located slightly to port. 

7.      Both radars should be situated so the conning officer can look at radar and out the window without changing position in order to compare the visual picture with the electronic one.  As portable DGPS units come into greater use it will be useful to be able to check all three sources of information without having to change position. 

8.      Multiple VHF radios should not be installed side by side.  With two radios close together it is difficult to determine which radio to pick up when being called.  Precious moments can be lost in an emergency if the wrong handset is used to reply.  The contact might be lost altogether.  A radio on each side of the centerline provides separation and makes it more likely one will be handy where needed.

9.      Radios should not be located in the immediate vicinity of the quartermaster.  He does not normally answer the radio and noise from the radio interferes with his ability to hear orders from the conning officer. 

10.  One popular VHF radio in use today has an LCD panel that can only be read from a position directly in front of the radio.  It is designed to be wall mounted and usually ends up at knee height below the forward windows.  To change channels the captain or pilot has to go down on their hands and knees.  In most situations this is just amusing and inconvenient.  In an emergency it will not be so funny.

11.  The engine order telegraph should be prominently mounted and clearly labeled with the standard commands of "dead slow", "slow", "half", and "full" for both ahead and astern.  In English, the words "full" and "slow" are often confused.  On pitch propeller controllers there is often only a series of lines so the pilot must guess if the pitch being given is the same every time.  Safety demands that orders be acknowledged and confirmed.  Make it easy for the conning officer to see that the mate understood and properly executed the order.  The buzzer or bell announcing a change of engine order should not be so loud that action on the bridge is suspended until the noise subsides.

12.  There should be rudder angle and RPM indicators on the bridge wing.  Bridge wings are the conning stations for the captain and pilot during docking.  This is a time when a missed order can be very expensive.  Orders are shouted back and forth to people inside or transmitted on a portable radio.  We need to verify that the orders were received and executed correctly when conning from the wings.

13.  Searchlight controls/switches should be conveniently located, well labeled, and prominently displayed so they can be easily found in emergency situations.  We have avoided many accidents by quickly illuminating the deck of our own vessel or by a quick flash at the other vessel to get his attention.  Of course sounding the correct whistle signals and exchanging information by radio come first, but there have been countless times as pilots where we have had to ask a tug boat to shine a light at someone to get his attention.  It’s another tool a mariner can use before the situation gets to be an emergency.

14.  If the forward view of the radar is obstructed by cranes and booms, the radar won’t detect targets ahead of the vessel.  This is unacceptable in any situation but is especially dangerous when navigating a narrow channel where the vast majority of traffic is coming from dead ahead.  The antenna can and should be mounted on the foremast if this is the case.

15.  Bridge noise levels are sometimes a problem.  It is common to have several VHF radios on at the same time (all on stations we are required to monitor).  Loud background machinery noise causes radio volumes to be turned up higher and personnel to talk louder to be heard over the background noise and radios.  The result is a bridge where there is tension and confusion.  The helmsman and mate can’t easily hear the captain or pilot’s orders.  The pilot can’t hear the repeat to ensure proper execution.  This leads to more shouting.   The most frequent source of high ambient bridge noise levels are radar and gyro power supplies.  On well designed bridges they are located in an electrical supply/equipment room behind the bridge.  Other sources include ventilation fans, air conditioners, wiper motors and transformers.  Equipment that must be on the bridge should operate quietly or be rejected as unsuitable.

16.  Modern bridges seem to get more indicator lights and warning lights each year.  All lights on the bridge should be equipped with dimmer controls.  All it takes is one bright light in the periphery of one's vision to make night adaptation impossible.  The usual solution for non-dimming lights is to put a book or a piece of paper over them.  If it’s an important indicator that’s a poor option.

17.  Give some thought about where the pilot and captain’s chair will go.  I have seen articles by old salts who deplore the use of a chair on the bridge.  Our average round trip is about 12 hours.  That’s a lot of time on your feet.  There are a lot of similar ports in the world.  Situate bridge consoles and equipment in a way that allows room for a chair with a person sitting in it at the conning station.  One would think it would not be necessary to ask that chairs not be mounted/welded to the deck directly behind a window frame that obscures the view dead ahead.  Sadly, it is necessary.  A survey of fixed chairs would show more than half of them in the mentioned position.   Welding a chair to the deck is a bad idea anyway.  They can be safely secured to a recessed pad-eye during rough weather, then released and moved as the situation changes. 

IV.  Miscellaneous  Vessel Characteristics

1.      We highly recommend a well designed Becker or Schiller rudder.  These rudders and their effect on maneuverability cannot be overstated.  They have been successfully used for over 20 years on many ships of different types and should be considered free from any taint of being experimental or new. 

2.      If a Becker or Schiller rudder is not possible, do not scrimp on rudder size.  Many formulas for rudder size yield a rudder that will satisfy minimum requirements for maneuvering at sea in deep, open water.  Considering that each voyage typically begins and ends in narrow, shallow, congested waterway this is a remarkably limited standard for such an important piece of equipment.  We have even seen standards that suggest larger rudders for vessels that “will spend significant time in port”.  This suggests that rudders should be designed for open water use.  A ship designed only for open water is like a golf club designed to be stored neatly in a golf bag.  Coming into port and hitting the ball are the critical tasks that must guide their design.  

3.      We don’t recommend CP propellers.  These propellers have limited and unpredictable effectiveness astern. This is a significant disadvantage. It is often suggested that the ability to go from ahead to astern quickly is an advantage with CP propellers.  Pilots would rather wait a few seconds for a reliable backing than have instant non-effect. In addition, steering is usually seriously degraded when speed is reduced. Getting consistent telegraph settings from watchstanders is difficult, and with the propeller constantly turning there is always danger of injury to linemen or getting lines caught in the wheel when docking.

4.      Install a quick rudder, 20 seconds from hard port to hard starboard.  A rudder that is slow getting into position detracts from its turning ability.  Due to strong, rapidly changing hydrodynamic effects as vessels pass each other in a narrow waterway it is often necessary to shift the rudder quickly at critical points in the maneuver.  In an emergency situation it is often necessary to put the rudder hard over in one direction to clear the bow from danger and immediately shift rudder hard over in the opposite direction to swing the stern clear.  Those seconds from hard over to hard over are the longest seconds in a mariner’s life.

5.      Maneuverability should conform to IMO standards on 20/20 zig zag test as performed on actual vessel or sister vessel. Tank tests, simulator trials or calculated values are not close to reliable.  We are dealing with more and more vessels that are slow to turn and even more difficult to steady up, especially larger vessels.  (See IV. 1 and 2 above.)

6.      Equip the ship with heavy duty bollards and chocks designed to accommodate the increased forces generated by modern tractor tugs. 

7.      Bridge forward designs should be avoided if possible.  They are more difficult to maneuver due the pilot’s inability to see the length of the vessel and judge its position in the waterway accurately.  If you don’t have experience maneuvering both kinds of vessel, try to imagine driving a bus that steers with the rear wheels instead of the front wheels.  Now, imagine you are sitting on the hood of the bus while you do this.   

Thank you for your interest.  Any and all input or discussion is welcome. 

Lvest@houston.rr.com