Collision Rules

All boaters, regardless of the size of their boat, should familiarise themselves with the International Rules for Preventing Collisions at Sea (Col Regs) and become aware of the basic rules on the water.

You should always make your movements clear and deliberate so that other masters can see your intentions. Never assume the master of another boat will observe the rules – always be prepared to take action to avoid a collision.

The Colregs give clear indication about passing, approaching, giving way and overtaking to avoid collisions with other boats. They are the traffic laws on the water.

Rivers and channels

Animated image showing boats passing in rivers and channels
A boat must always be navigated on the starboard side (right) of a river or channel.

Approaching head on to another boat

Animated image showing boats approaching head on
Each boat alters course to starboard (right) and passes port to port (left). Always assume this situation exists. 

Power-driven boats crossing

Animated image showing power driven boats crossing
A boat approaching from your starboard (right) side has right of way. If you are approaching another boat from its starboard side, you have right of way. However, if the other boat does not give way, you must take action to avoid a collision. 


Animated image showing boats overtaking
If you are overtaking a boat, you can do so at either side of the boat you wish to pass. However, you must keep well clear of the boat you are overtaking. This applies to both sail and power boats. 

Sailing boats and power-driven boats

Animated image showing sailing boats and power driven boats crossing
Animated image showing sailing boats and power driven boats crossing - large vessel
Power usually gives way to sail. However, this does not always apply. Larger vessels, such as ferries or container ships, have difficulty manoeuvring due to their size. Masters of other boats, including sail boats, should always apply common sense and good seamanship by giving larger vessels a wide berth. 

Sailing boats

Sailing boats with wind
When two sailing boats have wind on different sides, the boat with the wind on the port side must give way.
When both boats have the wind on the same side, the boat to windward shall give way to the boat to leeward. 

Copyright State of Queensland

Keep a Lookout

A good lookout through sight and sound must be kept at all times.

The master is responsible for keeping a lookout for dangers. Be aware of the boating environment, especially in bad weather, restricted visibility and darkness.

Sound Signals

Special sound signals exist for vessels to indicate their manoeuvring intentions when they are in sight of one another.

  • 1 short blast  – I am altering course to starboard
  • 2 short blasts – I am altering course to port
  • 3 short blasts – I am operating engines astern (stopping)
  • 5 or more short blasts – I am unsure of your intentions and I doubt whether you are  taking sufficient action to avoid collision


Code Flag A
The international Code Flag “A” is a blue and white vertically divided flag that indicates divers below. When displayed, this flag requires that boats do not exceed 5 knots when within 120 metres of it. This flag may be hoisted from an anchored vessel, on a buoy or dive float or hoisted on the shore. The flag must be at least 500mm high and at least 400mm wide.
Operation in Pilotage Areas

Recreational vessels often operate in shipping ports and channels. Small craft operators must be aware that large ships cannot alter course or speed quickly and often their draft restricts them to a very specific course. In addition, it is difficult to even observe small craft from the bridges of certain ships.

Code Flag H

The international Code Flag “H” is a red and white vertically divided flag that indicates that the vessel has a pilot on board. This flag is used when ships are approaching their berth and are under the control of a pilot. In such circumstances, the recreational skipper must keep clear of the ship at all times.
Vessel under Control of Exempt Master

Ships that enter ports regularly are occasionally exempt from using a pilot, however they still have right of way over all other craft. To indicate that they are under the control of an exempt master, these ships will display an all-white square flag.