Ship Operation

Hull, equipment and fittings

The hull is the body of the boat. It keeps water out and makes the boat float. The front is the bow, the back is the stern, the left side is port, the right side is starboard. The floor is the deck, and the bottom ridge is the keel.

Fittings are the smaller parts fixed to the hull: cleats or bollards for tying ropes, the anchor and its chain or rope, fenders (soft pads) to protect the boat when it touches a wall, navigation lights, a bilge pump to remove water from inside, and hatches that close openings.

Equipment includes the engine and propeller, rudder, compass, radio, fire extinguisher, lifebuoy and life jackets. A good operator checks all of them before every trip.

Steering

A boat turns by pushing water sideways. The rudder is a flat blade behind the propeller. When the rudder is turned, water hits it and pushes the stern one way, so the bow goes the other way. A boat with the rudder to the right turns to the right.

• A rudder works best when water flows past it. At very low speed it works weakly, so give it a little engine power.
• A boat does not turn on the spot. It moves in a turning circle. Big and fast boats need a large circle.
• The stern swings out the opposite way when the bow turns, so keep clear of walls and boats on the outside of a turn.
• Wind and current also push the boat. Steer with small moves and watch where the boat really goes.
• There are no brakes. To slow or stop, reduce the engine power early, and use reverse gently.

Basics of navigation

To go from one place to another we need to know three things: where we are, where we want to go and which way to point. The compass shows direction in degrees: north 0, east 90, south 180, west 270. The direction the bow points is the heading. The direction you want to travel along the chart is the course.

Tools: a chart (map of the water with depths and hazards), a compass, a GPS to show position, and your own eyes for landmarks and buoys.

Distance, speed and time: distance = speed x time. At sea, speed is in knots (1 knot = 1 nautical mile per hour = 1.852 km/h). Always keep a lookout and compare what you see with the chart.

Weather and sea conditions

The sea changes with the weather. Learn these points.

• Wind makes waves. Stronger and longer wind makes higher waves. Wave height is the distance from the bottom to the top of a wave.
• Visibility: fog, rain and haze make it hard to see other boats.
• Tides and currents move the water. A strong current against the wind makes steep, dangerous waves.
• Forecasts: listen to the official weather and sea warnings by radio, phone or port signals before you go and during the trip.
• Warning signs: dark and fast-growing clouds, a sudden change of wind direction, a swell with no wind, and a falling barometer (pressure gauge).

A simple sea-state ladder: calm (under 0.5 m), slight (0.5 to 1.25 m), rough (1.25 to 2.5 m), dangerous for small boats (higher). If the forecast is bad, do not go.

Voyage planning

A voyage plan is made before leaving. Steps:

1. Choose the destination and the route on the chart. Keep clear of shoals, rocks, nets and restricted areas. Mark waypoints (turning points).
2. Measure distance and work out time = distance / speed.
3. Work out fuel. A good rule is thirds: one third to go, one third to return, one third reserve.
4. Check weather, tides and sunrise/sunset. Plan to arrive in daylight.
5. Choose safe harbours on the way where you can shelter.
6. Check the boat, safety gear and radio. Tell someone ashore your route and return time.
7. Brief the crew on what to do in an emergency.

Heavy-weather navigation and accident prevention

Even a good plan can meet a storm. Stay calm and act in this order.

• Slow down: less speed means less pounding and less water on deck.
• Point the bow into the waves (a little to one side). Waves hitting the side make a boat roll and may capsize it.
• Close hatches and doors and tie down loose things. Water inside makes the boat heavy and unstable.
• Wear life jackets, keep low and hold on. Keep the lowest-weight items and people in the centre.
• Keep away from the lee shore (the coast the wind is blowing towards). Head for a safe harbour or deeper water.
• Call for help early on the radio, before things get worse. Give position and number of people.

Preventing accidents: collisions (lookout, rules), grounding (chart, depth, stay in channel), capsizing (load limit, trim, heavy-weather steps), fire (no smoking near fuel, extinguisher ready), man overboard (shout, throw a lifebuoy, keep eyes on the person, turn back slowly).

Try it

On a calm day draw a simple voyage plan for a trip you know (a ferry, a lake ride): start, destination, distance, speed, time, fuel and one safe place. Then think of one thing that could go wrong and what you would do.

Key formulas and definitions

• Parts: bow (front), stern (back), port (left), starboard (right), hull, deck, keel.
• Distance = speed x time; time = distance / speed.
• 1 knot = 1.852 km/h.
• Compass: N 0, E 90, S 180, W 270 degrees.
• Fuel in thirds: 1/3 out + 1/3 back + 1/3 reserve.

Worked examples

Common mistakes

• Thinking the rudder works the same at zero speed. It needs water flowing past it.
• Putting the boat side-on to the waves in a storm. Point the bow into them.
• Planning a straight line without checking the chart for shoals.
• Counting only fuel to get there. Always keep fuel for the return and a reserve.