The Bridge

THE BRIDGE

The nerve centre of any ship is the Bridge. Marine engineers can not understand this statement ! The bridge is always occupied by an officer on watch when the ship is in service. It was originally called a 'bridge' because the early paddle steamers were controlled from a structure built between the paddle boxes to provide good visibility - as it looked like a bridge, the name stuck !

The ship is also controlled from the bridge. The main controls are the steering wheel and engine telegraphs. However there are also the docking telegraphs , the communications systems, radar, charts and flags. Also on the bridge is the most important navigation tool from the days Balmoral was built - the compass. Today there is also an electronic chart plotter and GPS ( global positioning system) so that the Captain will know the position of the ship to about 2 meters anywhere in the world.

The bridge of a modern passenger ship may not be the highest point as designers like to give the people who pay the best view, and thus lounges and often a bar will be at the top of the ship, but the bridge will always have an excellent view ahead and to both sides, although it may not be possible to see the stern ( back ) of the ship and some of the communication and navigation facilities may be in adjacent areas. CCTV cameras and computer communications mean this isn't a problem on modern ships, but Balmoral is built to a traditional design. Her bridge is the highest point and contains all the navigation equipment and control systems - and apart from modern equipment like radar, GPS and VHF radios, she still has all her original fittings and they are used to navigate the ship.

STEERING

The ship is controlled by the Master ( Captain ) or an officer, but is usually steered by a seaman who responds to orders given to him by the person in control. These instructions can either be to keep the ship on a magnetic compass course and to adjust the steering so that the compass remains on a given heading, so that the ship is continuously pointing in a certain direction, or he can be told to steer by degrees - to turn the wheel and hence the rudder by a certain amount. Sometimes the Captain will ask the helmsman to steer at his discretion but he has to trust the man on the wheel as the Captain will be responsible if anything goes wrong !

However in the Bristol Channel, the tides and currents are so difficult that on Campbell's ships, it was not unusual for the Captain to steer the ship himself when approaching a pier or harbour!

As you can see, while the view ahead and to the sides is excellent, the view to the rear ( stern ) is awful, and unlike most new ships, Balmoral does not have extended bridge 'wings' that project over the side, so there is not much view of what is going on at the back. This is one of the reasons why it is necessary to maintain a continual lookout all round the ship and also why it is necessary to have what is known as a docking telegraph. We will look at these later.

Port and Starboard

Left and Right in nautical terms. The two sides are also defined by colors.

Port is Red

Starboard is Green.

An easy way to remember this is the saying : Is there any red port left ?

This is the wheel in the original wheel house and also the compass. The steering wheel controls the direction of the rudder and thus the direction of the ship, while the compass is used to keep the ship on a particular course. While this is not a problem when in sight of the shore and if the Captain knows where he is, but at night, in bad weather or when out of sight of land, the compass is a vital tool for navigation. The compass needle points in the direction of the Earth's magnetic North and is used to steer the ship, either by giving a direction in degrees or the old fashioned way by referring to points of the compass. So, steering 090 degrees ( zero nine zero ) would be due East. However before degrees were used, directions were split into cardinal points, not an issue when heading, say, West. However if you wanted to head a little bit to the west of north, the Captain would have to tell the man on the wheel to steer 'North West by North'- it is rather easier to tell the helmsman to steer 327.5 degrees in modern terms - less room for confusion and a lot more accurate !

This is a compass rose - North is 0 degrees, East is 090 degrees, South is 180 degrees and West is 270 degrees.

Computers don't understand words so modern navigation systems all work in degrees which is much easier and less likely to cause confusion.

The steering system mechanically links the steering wheel to the rudders via shafts and gear wheels that run the length of the ship. The steering is very low geared so that many turns of the wheel are needed to operate the rudder. Modern ships are computer controlled and many have a joy stick like a model radio control, but Balmoral has a traditional mechanical system.

In the 'steering flat' is a hydraulic engine that powers the rudders although this can be uncoupled and a reserve manual steering linked up in case of a breakdown. Thus the ship can be steered from the bridge or from the rear ( poop ) deck although this is hard work and would require a chain of commands to be sent along the deck ( or by walkie talkie radio as that's a lot quicker and only needs one person at each end of the communication chain !) so that the man on the bridge can tell the man on the wheel what to do. However when all is going well, the system is fully automatic and a light touch on the steering wheel on the bridge will immediately alter the position of the rudders - although the system will take a few seconds to respond and the ship, as she weighs about 750 tons will take much longer to react. Thus it is important to anticipate and to plan ahead.

The steering is not like a car as it depends on water flowing over the rudders to alter direction. This is a factor of the speed of the ship and also the speed and direction of the propellers. When going ahead ( forwards ) there is plenty of water flow and the rudders are effective as there is something to push on. Going astern ( backwards )there is very little flow and the ship is not as easy to maneuver. In this case, the Captain can use the engines to assist. As there are two propellers, one on each side, the direction of each can be altered and the speed varied so that the ship can be pulled round by one going ahead and the other astern on each side. The ship does not turn like a car as the rudders and propellers are at the back. Instead the back of the ship swings out during a turn and the hull pivots around a point somewhere under the bridge - this takes a lot of getting used to as the turning the wheel one way actually pushes the back of the ship the wrong way and this carries on for several seconds before the bow ( front ) begins to turn in the desired direction.

That is the easy part of steering - the rest is called navigation and is the science of getting the ship to its destination without hitting anything or running aground.

NAVIGATION

The problem on water is that you can't see what is under the surface and its always moving- and if you hit something like a rock or a wrecked ship, your boat may sink. Tides also flow in and out which causes the water to move at varying speeds at different times of the day and depending on where you are. At Clevedon the tide can be 6 knots while at Southampton it may be half that, and the water level rises and falls up to 15 meters in the Bristol Channel in the space of 12 hours, so you have to know if there is enough water to float your ship and enough depth to avoid any obstructions on the bottom. There is also the effect of wind on the ship and all these factors have to be calculated. The one thing you can be certain is that the ship won't actually travel in the direction it is pointing. So you need to factor all this into he direction in which you point your boat.

Then you have to know which way its actually going. The main tool for navigation in the days when Balmoral was built was the compass. This is a direction indicator that always points to the Earth's magnetic North. It is held in gimbals that allow it to move as the ship rocks and rolls so that it is always level and is very accurate. If you have a map of the sea area you are in ( a chart ) then you can work out where you are by taking sightings on land marks and by working out the direction ( bearing ) of each one from your position you can draw lines on the chart to show where you are - or were when you started taking the measurements! Thus all you need to do is to know where you are, where you want to go and to join the two with a line on your chart - the direction of the line in degrees will be the reading on the compass you want to steer.

If only it was that simple ! Your chart is drawn on a fixed direction system known as True North so that every one has a similar orientation, but compass works on Magnetic North which varies slightly every year and needs to be taken into account before you can convert the magnet direction ( Magnetic Deviation ) to the true direction. To make it even worse, most large ships are made of steel, or have steel parts, this will affect the way the compass needle points. This wouldn't be very important in an all wooden dinghy, but in a steel ship it can create a huge error and the compass would be useless - or worse give the wrong readings so that you were making mistakes. Over long distances, even one degree of error can make a huge difference to the destination and many ships have been wrecked because the compass was incorrect. There are two red and green balls which hold magnets either side of the compass. Before the ship sails, the compass is adjusted so that as much of the error is removed by changing the magnets round the outside of the instrument and any remaining errors are written down on a 'deviation card' so that the officer doing the navigation and working out where the ship is heading can take all this into account. He also has to take the tides, currents and wind into account, so navigating a ship is an extremely complicated business.

Thus when you want to go in a particular direction, the tide and wind will push the ship in different directions, the speed and direction over the ground ( course over ground COG ) will not be the same as the direction through the water, and the compass direction won't be showing where you want to go - and the water and the local direction and speed of the tide may alter - all at the same time. So, although you want to go in a particular direction, you may have to point the bow of the ship somewhere else - and working out what direction that is, is up to the navigator ! These days its all done using electronic chart plotters and GPS, but when Balmoral was built it was done by hand and even today, all bridge officers must be able to navigate traditionally - if there is a problem or the power fails, not being able to steer the ship where you want to go isn't an option !

CONTROLLING THE ENGINES

If you are an engineer, then the engine room telegraph is the most important part of the control system. Modern ships have computer controlled engines and the man on the Bridge presses buttons and uses a lever to control the engine speed and direction of the propellers. On Balmoral, she has a traditional system of engine room telegraphs. There are two dials for each engine and in the engine room, an engineer is stationed beside each one.When the Captain wants to alter the engine output he 'rings down' to the engine room by moving the handle for the appropriate engine. The telegraphs are linked and duplicated on the other side of the bridge. Moving the lever operates a gong in the engine room that can be heard above the din of the engines and the pointer will then move to the required command. The engineer's first job is to confirm the command by altering his own pointer and this moves o the bridge telegraph so that the arrow will point to the position the Captain has requested. Once that is done , the engineer alters and engine and gearbox controls to adjust the engine speed and propeller direction. The system is a mass of chains, pulleys and linkages but once adjusted is very reliable, although there are two back up systems, a set of lights and a system of bell rings. It is very unusual for the system to fail but if it did, there would be no problem as the reserve system is immediately available. There is also a note pinned up in the engine room as a sort of 'if all else fails' instruction - 'continuous ringing of the bell means full astern' !! . ...just in case !

In addition to ahead and astern, the telegraph has a positions for 'stand by' . This is to tell the engineers that they will soon be needed. On a long run there is no need to have the men waiting for an instruction to alter the engine speed until the ship is approaching its destination. As it gets near, the Captain will ring down 'stand by' to tell the engine room crew to be prepared to respond to commands. Likewise when the ship is tied up to the quay and the engines can be shut down, the bridge will ring 'finished with engines', releasing the engineers from continual duty. This saves manpower and a lot of boredom !

There is also a speaking tube system on Balmoral. This is long out of use on modern ships, but before hand held radios, you had a pipe that ran from the bridge to the engine room control station. At each end was a plug with a whistle built into it. If someone at one end wanted to speak to the other,, they removed their plug and blew hard down the pipe. This caused the plug at the other end to whistle, so the receiving end removed their plug, put their ear to the opening .... and could just about hear what was being shouted from the other end. Simple, reliable two way communication - and it usually worked !

On the bridge, the engine room telegraph... each of the brass levers is connected to a dial above the engine control station on that side of the ship ....................

SOUND SIGNALS

The bell used to be used for time signals but is not of great significance these days. Balmoral's bell is from the Bristol Queen paddle steamer as the original was stolen. It is not left on board during lay-up !

All ships need a hooter and Balmoral's works from the engines compressed air supply. It is EXTREMELY loud and always scares the life out of passengers on the foredeck - however it needs to be loud as it has to be heard by other ships over the noise of wind and engines.

Like most things on a ship, it has several other uses. It serves as a signal to evacuate the vessel in an emergency and also tells other water users what the ship intends to do next. In crowded waters where there may be people without access to a radio it is easier to use a sound signal. In this case the horn. If you hear a series of short hoots from a ship, they are not just given because its saying hello - every signal has a code. A short blast on the horn is about a second. A long blast is about 5 seconds.

There is quite a complicated code for informing other ships you are there, that you are turning, you have run aground and even a couple of unofficial rude ones. Here are a few of the more common ones:

One long blast: I am here - I am about to start moving or .... OI! WAKE UP !!

One short blast: I am turning to starboard.

Two short blasts: I am turning to port.

Three short blasts: My engines are going astern - this does not necessarily mean that the ship is going backwards, just that the engines are running in reverse.

Five short blasts: What are your intentions ? More commonly it means 'get out of my way' and is very popular in the Solent at holiday times.

Six short blasts: unofficial - IDIOT !

Seven short blasts: unofficial and often accompanied by hand gestures: Your mother was a walrus and you have inherited her looks and intellect. This is uncommon as it can be mistaken for:

Seven short and one long blast: Call to muster stations for possible abandoning of the vessel.

In fog there are further sound signals that have to be used to advise other ships of your presence and what you are doing.

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