Free boating theory questions and short answers
Search-friendly answers for Day Skipper theory, Marine Radio SRC, VHF procedure, buoyage, lights, tides, CEVNI and practical revision. Each page has one question, a short answer, a mini quiz and a link to revise the full topic.
Sailing theory subject map
Learn by topic before testing recall
Each topic guide teaches the essential framework, then links to selected short-answer questions and a practical next step.
Boat terminology
8 questionsLearn the directional words, parts and working terms that make instructions aboard a boat precise.
Open topic guideNavigation & chartwork
11 questionsBuild chart-reading, position, distance, speed, time and compass skills in a safe working order.
Open topic guideTides
3 questionsUnderstand what tidal heights and tidal streams mean, which inputs belong together and where safety margins enter.
Open topic guideBuoyage
4 questionsRecognise lateral, cardinal and other common marks without memorising colour in isolation.
Open topic guideCEVNI inland waterways
8 questionsUnderstand how CEVNI, national rules, local signs, commercial traffic, locks and bridges fit together on European inland waterways.
Open topic guideCOLREGs
3 questionsLearn a disciplined lookout-to-action sequence for vessel encounters, lights, shapes and sound signals.
Open topic guideWeather
3 questionsConnect pressure, wind, sea state, visibility and forecasts to passage decisions without over-reading one sign.
Open topic guideMarine radio
12 questionsUnderstand listening watch, channel choice, DSC and the difference between distress, urgency, safety and routine traffic.
Open topic guideSafety
4 questionsUse layered controls for people, equipment, environment and emergencies instead of relying on one item of gear.
Open topic guidePassage planning
1 questionsCombine pilotage, tides, weather, navigation, crew and alternatives into one usable plan.
Open topic guideBoat handling
3 questionsUnderstand how wind, stream, propeller, rudder, momentum and lines shape a controlled manoeuvre.
Open topic guideStart with common searches
Buoyage
What colour is a port-hand mark in IALA Region A?
A port-hand mark is red in IALA Region A.
Marine Radio SRC
What is the difference between Mayday and Pan-Pan?
Mayday is distress with grave and imminent danger; Pan-Pan is urgency without immediate grave danger.
Marine Radio SRC
What is the difference between VHF Channel 16 and Channel 70?
Channel 16 is for voice distress, urgency, safety and calling; Channel 70 is for DSC signalling only, with no voice traffic.
Lights and shapes
What is an isophase light?
An isophase light has equal periods of light and darkness.
Tides
How do you calculate tidal height for a simple depth check?
Add the height of tide to the charted depth, then compare the result with draught plus a safety margin.
Signal flags
What does a yellow flag mean on a boat?
A plain yellow Quebec flag means the vessel is healthy and requests free pratique.
Garbage
Under MARPOL Annex V, which garbage must not be deliberately discharged at sea?
Plastics
Depth planning
Which sequence correctly turns compatible chart and tide inputs into a depth decision?
Charted depth plus tide height, then compare with draught and safety margin
Red shore control
A red lock signal remains displayed while the chamber appears empty. What is the defensible action?
Hold outside until the signal permits entry
Crossing targets
How should a crossing contact be assessed?
Use timed range/bearing, the applicable visibility Rule context, whole-picture action and fresh checks
Datum and depth
What is Chart Datum approximately equal to in most UK tidal waters?
Lowest Astronomical Tide
Blue signal distinction
Which statement preserves the exact distinction between CEVNI blue dangerous-goods and authority signals?
Steady blue counts mark cargo categories; a blue scintillating light marks an authorised role
Recognition method
Which observation report is strong enough to support a CEVNI vessel-light interpretation?
Report every cue, its context, meaning and required action
Meeting traffic
What should shape a CEVNI meeting decision before two vessels enter a narrow fairway?
Classify the meeting, read the signs and scope, and prove the full fairway is wide enough before either vessel commits
DSC fundamentals
Which channel is used for VHF DSC digital signalling?
Channel 70
Working channels
Why should detailed routine traffic move from an initial calling route to a suitable working channel?
To keep the calling and safety route clear
Scope
What does scope describe in this small-boat anchoring plan?
The ratio of cable paid out to the planned vertical distance from its lead to the seabed
Position coordinates
For practical Mercator chartwork, one minute on the nearby latitude scale represents what distance?
One nautical mile
Terms
On a vessel's sidelights, what colour marks the starboard side?
Green
Terms
If a crew member is asked to move aft, where should they move?
Towards the stern
Terms
What is the 'draught' of a vessel?
The depth of the hull below the waterline
Terms
What does a halyard do?
Hoists a sail up the mast
Terms
What is 'leeward' and how is it pronounced?
Away from the wind — 'loo-ard'
Terms
What is 'freeboard'?
The height of the deck above the waterline
Terms
What is the 'kicking strap' (vang) used for?
Holding the boom down to control mainsail shape
Terms
What does 'abeam' mean?
At right angles to the vessel's centreline
Terms
What is the difference between a 'shroud' and a 'stay'?
Shrouds support the mast from the sides; stays support it fore and aft
Terms
What does amidships mean?
The middle area of the vessel
Coastal planning
What is a lee shore and why is it considered dangerous?
A shore towards which the wind blows — dangerous because wind and waves can reduce sea room and drive the vessel towards danger
Direction and movement
What is the difference between 'course' and 'track'?
Course is a specified intended or steered direction; track is the actual path made over the ground
Coastal planning
In navigation, what is 'fetch'?
The distance over water for which wind blows in a broadly consistent direction—one factor in wave development
Direction and movement
What does 'making good' a course mean?
Actually achieving the desired track over the ground; planned corrections may help, but the result is observed
Coastal planning
What is a transit in navigation?
Two identified charted objects observed in line, giving one line of position without a compass
COLREG terminology
What does it mean when a vessel is described as 'making way through the water'?
The vessel is moving relative to the surrounding water
Direction and movement
What is the difference between 'heading' and 'bearing'?
Heading is the direction the bow points; bearing is the direction of an external object measured from the vessel or from north
Special marks
What should you do with a yellow special mark?
Check the chart and current publication to identify its purpose, limits and route implication
Hazard marks
Which mark sits on or close to a small hazard with navigable water around it?
An isolated danger mark, with the chart used to resolve the danger's extent and passing distance
Terms
What does it mean to 'gybe'?
To turn the stern through the wind
Shared-channel operation
What should you do before making a routine marine VHF voice call?
Listen and confirm the channel is clear of existing or higher-priority traffic
Distress threshold
A yacht is being driven onto rocks, cannot arrest the approach and needs immediate outside help. Which priority is appropriate?
Mayday, because the danger is grave and imminent and immediate assistance is required
Operator authority
A boat has a Ship Radio Licence and an MMSI. What separate operator condition applies to ordinary SRC-covered use?
An appropriate operator certificate, or direct supervision by someone who holds one
Distress alerting
What is an EPIRB's primary alerting function?
Send a vessel-associated 406 MHz distress alert through the satellite system
Safety information
What may safely be concluded from an AIS display with no target at the harbour entrance?
Only that no received AIS report currently creates a displayed target
MMSI
What does an MMSI identify?
An assigned maritime radio station or group identity
Routine voice procedure
Which phrase correctly introduces your own vessel identity in a routine voice call?
This is
Lock preparation
A small craft reaches a lock before a commercial vessel and both will share it. When should the small craft enter?
Only when invited by staff, after the other vessel, even though it arrived first
Radar picture
What does a radar display show?
Returned energy needing interpretation
Harbour approach
What is the safest response to an uncertain harbour radar picture?
Slow, hold safe water or wait, and rebuild the picture before entering
Applied understanding
A learner recognises a bridge signal but cannot say what action it requires or what local fact remains to be checked. What is missing?
The operational consequence and evidence limit: whether to stop, wait, pass, call or use another opening, plus the current local control
Competence boundary
Why is passing a CEVNI multiple-choice test not enough preparation for a busy commercial waterway?
Knowledge evidence does not demonstrate current handling, lock, radio or command competence around constrained traffic
Helm handover
What should happen during a helm handover?
Deliberate control handover, kill cord transfer, and maintained lookout
Passage planning
A familiar short trip is proposed. What is the governing purpose of its passage plan?
To connect route, conditions, boat, people, timing, alternatives and monitoring so decisions retain margin
Calling channels
Which description of Channel 16 is operationally correct?
It carries distress, urgency, safety and initial calling by voice; routine traffic moves away promptly
Operating loop
Which sequence best supports a radar-based decision in a developing traffic situation?
Check, observe, cross-check, decide within limits and monitor
Coastal planning
What is a weather shore?
A shore from which the wind is blowing; it may reduce local fetch to leeward but does not guarantee shelter
Safety
Why must you NEVER attach a helicopter winch wire to the boat?
The helicopter could capsize the vessel if it needs to pull away
Prohibitory scope
A.5 tells vessels not to berth on the side where the board is placed. Which interpretation is complete?
It is prohibitory and removes both anchoring and making fast on that side
Radar fixing
What is essential before using a radar echo for a fix?
Positive identification of the fixed charted feature
Blind areas
A blank wedge remains on the same relative bearing when the boat changes heading. Which cause should be investigated first?
An onboard blind or shadow sector
Lookout
Even with radar operating normally, which duties and evidence remain part of the decision?
Proper lookout, safe speed, required sound signals, all appropriate available means and COLREG judgement