Basics of ship handling
Ship handling (also called manoeuvring) is controlling where the ship goes and how fast.
The tools are the engine and propeller (speed), the rudder (direction), and sometimes bow thrusters (side propellers) and tugs. The rudder is a flat plate behind the propeller. When it turns, the water pushes the stern to one side, so the bow swings the other way. The ship pivots around a point about one-third of the length from the bow.
Important ideas: helm orders are clear spoken words like "starboard ten" (turn rudder ten degrees to the right), and the helmsman repeats them back. The turning circle is the path of the ship when the rudder is held over; it is much larger than the ship. A ship has a lot of inertia, so it keeps moving after the engine stops. This is why we measure stopping distance in ship lengths.
Advanced ship handling
Advanced handling is about working in tight places and with outside forces.
Wind and current. Wind pushes on the tall sides of the ship; current moves the whole water the ship floats in. Both cause leeway and drift. The captain aims a little into the wind so the ship ends up on the right line (this is called making a crab angle).
Berthing and unberthing. The ship approaches the pier slowly, at a small angle, stops with the engine going astern (reverse), and is held by tugs and ropes. Shallow water and narrow channels: when the ship is close to the bottom or a bank, water squeezes and the ship sits lower (this is called squat) and steers badly, so speed must be lower. Anchoring: the ship approaches the spot slowly into the wind, drops the anchor, and lets out chain about three to five times the water depth.
Rules of the road (collision regulations): two ships meeting head-on each turn to starboard (right); the give-way vessel acts early and clearly.
Heavy-weather seamanship
In a gale or typhoon the sea is dangerous. Good seamanship means prepare early, slow down, and keep control.
- Prepare: close hatches and doors, lash down gear, check pumps, tell everyone, and get the latest forecast.
- Reduce speed so that the ship does not slam into waves.
- Heading: keep the bow about 20 to 30 degrees off the waves. Waves hitting from the side (beam seas) can make a ship roll heavily and even capsize, and waves from behind (following seas) can push the stern around (this is called broaching).
- Avoid the typhoon: a ship in the north should leave the dangerous right-hand side of the storm, where wind and storm movement add up.
- If it is too rough, heave to (keep the bow into the waves at slow speed) or run to a safe port.
Marine accidents and emergency response
Common marine accidents are collision (two ships hit), grounding (ship hits the sea bottom), fire or explosion, flooding and sinking, capsizing (turning over), and man overboard. Most are caused by human error: tiredness, poor lookout, wrong speed or ignoring rules.
General emergency steps: 1) Raise the alarm. 2) Save life first. 3) Send a distress call ("Mayday") with the name and position. 4) Control the danger: stop leaks, fight fire, reduce speed. 5) Prepare to abandon ship only on the master's order, with lifejackets on.
Man overboard: shout "man overboard", throw a lifebuoy, mark the position, turn the rudder fully towards the side where the person fell (so the stern and propeller swing away), then do a Williamson turn or similar circle to return along the same track. Keep eyes on the person.
Collision or grounding: stop the engines, check for leaks, and do not reverse off if the hull is holed. Call for help first.
Try it
In the 3D: set the rudder to 10, 20 and 35 and count how wide each circle is. Then use Engine stop at slow and at fast speed: which gives the longer stopping distance? Add some wind and try to keep the ship on a straight line by steering. At home: roll a toy car on a smooth floor, stop pushing, and measure how far it coasts. Do it again faster.
Key formulas and definitions
- Helm order example: "Starboard ten" = rudder 10 degrees to the right.
- Stopping distance grows quickly with speed (roughly with the square of speed).
- Distance (nautical miles) = speed (knots) x time (hours). 1 nautical mile = 1.852 km.
- Anchor chain length = about 3 to 5 x water depth.
Worked examples
1. A ship travels at 10 knots for 3 hours. How far does it go in nautical miles and in km?
Distance = 10 x 3 = 30 nautical miles. In km: 30 x 1.852 = 55.56 km, about 55.6 km.
2. A ship is 150 m long and needs 8 ship lengths to stop. How many metres is that?
8 x 150 = 1200 m, which is 1.2 km.
3. Water depth is 15 m. The captain pays out chain 4 times the depth. How much chain?
15 x 4 = 60 m of chain.
Common mistakes
- Thinking a ship stops as fast as a car. A heavy ship glides for many ship lengths.
- Holding the rudder over and expecting an instant turn. The turn builds up slowly.
- Forgetting wind and current. The ship's nose direction is not always its real path.
- Taking waves side-on (beam seas) in heavy weather. Bow-on at a slight angle is safer.
- Reversing off after grounding or holing. This can make the leak worse.