Pilotage & VHF DSC Basics Flashcards

What is the purpose of a 'clearing bearing' in pilotage?

Answer: A compass bearing that, when maintained, keeps the vessel clear of a specified hazard

A clearing bearing (also called a danger bearing) is a pre-planned compass bearing that defines the outer boundary of a danger. Keeping the bearing greater or lesser than this value keeps the vessel safe.

In a pilotage plan, the term 'mark abeam' refers to:

Answer: The moment a charted feature is directly to the side of the vessel (90° to heading), used as a timing or turn trigger

A mark abeam is used in pilotage to trigger a course alteration or confirm position — when the mark is directly to port or starboard, it confirms you have reached a precise position line.

A marina's approach chart shows a leading line of 270°T. Approaching from seaward on an easterly course, the skipper should:

Answer: Line up the two leading marks and steer 270°T — the reciprocal leads into the marina

Leading lines show the safe inbound track. If the leading line direction is 270°T, approaching from seaward means coming FROM the east and steering 270°T (westward) into the marina.

On a VHF DSC radio, what is Channel 70 used for?

Answer: Digital Selective Calling (DSC) distress and safety calling only — voice communications must not be made on this channel

Channel 70 is reserved exclusively for DSC (Digital Selective Calling) distress, urgency, and safety alerts. No voice communication is permitted. All GMDSS-equipped vessels must keep a DSC watch on Ch 70.

A skipper enters a port for the first time in poor visibility. Which is the safest pilotage approach?

Answer: Use pre-planned waypoints, transits, and clearing bearings; proceed at reduced speed; sound fog signals

Best practice in restricted visibility is to use all pre-planned pilotage features (transits, clearing bearings), reduce speed, post a good lookout, and make regular sound signals (fog signals) per COLREGs Rule 35.

What is the MMSI number on a DSC radio?

Answer: A unique 9-digit identifier for the vessel used in DSC transmissions — similar to a telephone number for the radio

Maritime Mobile Service Identity (MMSI) is a unique 9-digit number programmed into a DSC VHF radio. When a distress call is sent, this number identifies the vessel automatically to rescue services.