Intermediate Cruising · Instructor Review Guide

Teach the Review

Every exam answer, plus the why behind it — your talking points for the table.

42questions

140/200to pass · 70%

2hrstime limit

How to run this with a crew. Tap a topic chip to jump to a section, then tap any section header to expand it. Each topic gives you the exam answer a student needs to write, a teaching point for how to deliver it, and the why so you can field the follow-up question. Work top to bottom — it follows the exam order.

Exam answerThe fuel & range chain

Two burn rates to memorize: diesel ≈ 0.1 L/hp/hr, gasoline ≈ 0.3 L/hp/hr. Then it's one chain of multiply-and-divide.

Burn rate20 hp × 0.1 = 2.0 L/hr

Running time60 L ÷ 2.0 = 30 hrs

Range30 hrs × 5 kn = 150 nm

Teaching point. Don't let them memorize "150." Make them say the units out loud — hp × (L/hp/hr) cancels to L/hr; L ÷ (L/hr) cancels to hr; hr × kn = nm. If the units land on nautical miles, the arithmetic is almost always right. This is the same skill they'll use on the nav questions in Section 10.

Why diesel sips and gas gulps. Diesel engines run lean and at high compression, so they extract far more work per litre — roughly a third of the fuel for the same horsepower. That's also why almost every cruising auxiliary is diesel: more range, no spark ignition to fail, and the fuel doesn't form an explosive vapour in the bilge.

Q1d / Q1eWhat else changes the range

Engine-related

State of tune / RPM
Number of cylinders
Propeller type & size

Everything else

Sea state, wind, current
Hull fouling / condition
Towing a tender
Helming ability
Motor-sailing (adds range)

Take it to sea. The exam stops at 150 nm — the seamanship lesson is the one-third rule: a third of fuel out, a third back, a third in reserve. So that 150 nm theoretical range is really a 50 nm comfortable passage. Tie it to passage planning: range is a number you plan conservatively, because the day you need it is the day the wind died and the current turned.

Q2Water per person, per day

2 Lsurvival minimum (no shower) — ½ US gal

8 Lcomfortable daily (no shower) — 2 US gal

Q2dConserving water — name 3

Never let taps run (teeth, face)
Fill sinks half full
No showers aboard
One marked cup per person, reused
Dilute dish soap — fewer suds to rinse
Hand / foot pumps, not pressure
Sea-water rinse, fresh-water final

Why the gap between 2 and 8. The 2-litre figure is pure physiology — that's what the body loses and must replace to keep functioning. The 8-litre figure folds in cooking, dishes, and washing up. The teaching message: water is the one consumable you cannot improvise at sea, so you plan tankage for the comfortable number and you know the survival number for when the tank cracks.

Q3Beating seasickness before you leave — name 3

Take medication well in advance (it's preventive, not a cure)
Eat light, non-greasy, easily digestible
Avoid alcohol and coffee
Get a good night's rest
Pre-make food and stow it handy
Keep foul-weather gear within reach

Q4Crew on deck who feels ill — name 3

Give them a job — put them on the helm
Eyes on the horizon
Keep them warm
Nibble plain crackers
Flat ginger ale or ginger tea
Stay out of the cabin
Sea-bands (acupressure wrist)

The why behind every remedy: sensory conflict. Seasickness is your inner ear (which feels motion) disagreeing with your eyes (which, below deck, see a room that looks still). The brain reads the mismatch as poisoning and triggers nausea. Every good remedy closes that gap: the helm lets you anticipate the boat's motion instead of being surprised by it; the horizon gives your eyes the same "we are moving" signal your ear has; staying on deck avoids the still-looking cabin entirely. Frame it that way and students never have to memorize the list — they can reconstruct it.

Q5If they must go below

Lie down, as close to midships as possible, and as low as possible.

Why midships and low. The boat pitches around a point near its centre and rolls around its keel. Midships and low is the spot with the smallest arc of movement — the bow and the masthead trace huge sweeps, the centre barely moves. Less motion in, less conflict, less nausea. Same physics as choosing a seat over the wing of an aircraft.

Q6Cruising clothing — list 6

Shade hat & sunglasses
Non-marking deck shoes
Sailing gloves
Foul-weather jacket + pants
Tuque / warm hat
Deck boots
Fleece / sweater / windbreaker
Warm socks

Q6bThe three-layer system

BasePolypro, silk or wool — wicks sweat off the skin

MidFleece or wool — insulates, traps warm air

OuterWindproof + waterproof — sheds wind & spray

AvoidCotton — soaks up water and stays wet

Why "cotton kills." Water conducts heat away from the body about 25× faster than air. Cotton holds water against the skin and won't let go, so a wet cotton shirt becomes a permanent cold compress — that's how hypothermia starts on a 15°C day. Wool and synthetics keep insulating even when damp because they trap air, not water. The layering system is really a moisture-management system: move sweat out (base), hold warm air in (mid), keep weather off (outer).

Q8Marine tool kit — 6 items

Pliers — needle-nose, vise-grips, channel-lock
Wrenches — adjustable + fixed, metric & imperial
Wire cutters & strippers
Screwdrivers & bit set
Hacksaw + spare blades
Allen keys / socket set

Q9Engine spares kit — 6 items

Raw-water pump impeller
Alternator belt
Fuel filter(s)
Assorted hose clamps
Assorted hose
Fuses
Spark plugs (gas engine)
Oil & coolant

Make the spares list make sense. Don't read it as a random list — read it as "the parts that strand you." The impeller and belt are the two most common roadside failures: a chewed impeller means no engine cooling (Section 7, Q21d) and a snapped belt means no charging. A clogged fuel filter is the number-one cause of a diesel dying. Carry the part and know how to fit it — a spare impeller in the locker is useless if no one has changed one.

Q7aMarine head — the sequence

Open seacock; valve to WET
Pump a little water into the bowl
Valve to DRY
Use the head
Pump the bowl empty
Valve to WET; pump to clean the bowl
Valve to DRY; pump bowl dry
Close the seacock

Why "dry" then "close the seacock." Leaving the valve wet and the seacock open lets the sea siphon back through the pump and slowly flood the boat through the toilet — a classic way that boats sink quietly at the dock. Pumping dry and closing the seacock breaks that siphon. And Q7b's "nothing that hasn't been swallowed first" rule is about the macerator: anything fibrous jams the pump, and the moment pumping pressure suddenly rises, STOP — you're about to break something you'll be elbow-deep in fixing.

Q11aCooking underway — 3 precautions

Gimbal the stove so it stays level as the boat heels
Pot clamps / fiddle rails to hold pots
Guard rail in front of the stove
Fill pots only half full
Cook wearing foulie pants & boots
Never stand downslope of a hot pot

Q11bPropane safety — 3 precautions

Tanks in a sealed locker vented overboard at the bottom
Light the match before turning on the gas
Shut the solenoid first to burn off the line, then the stove
Electronic propane detector at the cabin sole

Why propane terrifies experienced sailors. Propane is heavier than air. Any leak sinks straight to the lowest point of the boat — the bilge — and pools there invisibly until a spark sets off the whole hull. That single fact explains every rule: the locker vents at the bottom so a leak drains overboard instead of into the boat; the detector sits low where the gas collects; you burn off the line by closing the solenoid first so no gas is left in the hose. Contrast with CNG/natural gas, which is lighter than air and vents up and out — propane is the dangerous one precisely because it falls.

Q12Stove fuels — true / false

F Alcohol burns hotter than gas with a visible flame — no, it's cooler and nearly invisible
T Alcohol burns best when vaporized by heat
F Alcohol can't be put out with water — water extinguishes it
T Kerosene can burn sooty if used improperly
F Kerosene doesn't burn hot — it burns hot
F Kerosene costs more than alcohol — usually cheaper

Teaching hook for alcohol. Its danger and its safety are the same fact: the flame is nearly invisible and water-soluble. You can't always see an alcohol fire (so respect it), but you can drown it with the nearest cup of water (so it's the forgiving galley fuel). Propane you'd never throw water on a leak — alcohol you would.

Q13Heating systems — true / false

T Forced-air (Espar/Webasto) gives uniform heat but is costly & complex to fit
T Bulkhead liquid/solid-fuel heaters need a stovepipe exhaust
F Electric heaters run on 12V with little drain — they're huge battery hogs

Q14Vessel power supply

DC charging

Engine alternator
Solar panels
Wind generator

120V AC

Shore power
Diesel generator
Inverter

Two battery banks? One "house" bank runs lights and instruments and can be drawn down. A separate start bank is kept full and untouched so you can always start the engine — flatten the house bank and you're still not stranded.

Q15Less fridge power — 3 ways

Pre-chill / pre-freeze food before loading
Keep it full — less air to re-cool
Organize so the door opens briefly
Freeze water bottles as ice blocks
Add insulation
Run the fridge while the engine charges

Why a full fridge is an efficient fridge. A fridge doesn't cool food — it removes heat from the air, and air re-warms instantly every time the lid opens. A full box is mostly cold mass (food, frozen bottles) that holds temperature, so the compressor cycles far less. On a boat the compressor is your single biggest 12V draw, so this is really a battery lesson disguised as a galley lesson.

Q16Electric windlass — 4 considerations

Switch off at the breaker when not in use
Keep fingers, hair, clothing clear of the gypsy
Engine running while the windlass works (huge current draw)
Never break the anchor out with the windlass — motor the boat up over it
Always set a snubber on the rode
Don't run it continuously — let the motor cool

The one that costs money. "Never break out the anchor with the windlass" is the rule that saves a deck. The windlass lifts chain — it is not built to drag the whole boat forward against a dug-in anchor. Use the engine to motor up over the anchor until the rode is vertical, then the windlass only has to lift the anchor's weight, not the boat. Otherwise you tear the windlass off the foredeck.

Q17Match the sail-handling system (A–F, each used once)

D · Headsail sheets used to pull the headsail out, and eased when it is furled in
A · Lazy jacks can hook the battens and prevent raising or lowering the main
C · In-boom furling accommodates battens parallel to the boom
E · Headsail furling line eased when unfurling, used to furl the headsail in
B · Stackpacks integrate lazy jacks with a top-opening mainsail cover
F · In-mast furling can prevent the main from lowering if it jams while furling

On "headsail sheets pull the sail out" — name the confusion. This is the official answer (option D) and it surprises people, so meet it head-on. On a roller-furling genoa two lines work as a pair. To deploy, you ease the furling line and sheet on — the working sheet is what physically drags the clew aft and unrolls the sail. To stow, you ease the sheet and haul the furling line, which rolls it back in. So, per the exam: the sheet pulls the sail out (D); the furling line furls it in (E). The sheet's everyday job is trim — but on a furler it's also the muscle that unrolls the sail.

Q37Trim — the numbers to write

Headsail car: set so the sheet points at the centre of the luff's leading edge
Reefing the genoa → move the car forward
Un-reefing → move the car aft
Good main trim: top batten parallel to the boom
Good main trim: top telltale streaming aft > half the time
Too much heel: drop the traveler (before reefing / in a gust)
Boom position is set by: mainsheet · vang · traveler

Why the genoa car moves forward as you reef. The sheet should pull evenly on the foot and the leech of the sail. Roll some sail away and the clew moves up and forward, so the old car position now pulls too much on the leech and not enough on the foot — the bottom of the sail goes baggy and the top flogs. Sliding the car forward re-aims the pull at the new clew and keeps the whole sail working. The mantra: "reef forward, shake-out aft."

Telltales and the top batten — what they're telling you. The top telltale streaming aft means air is flowing smoothly over the whole sail; if it stalls and droops, the top is over-trimmed. The top batten parallel to the boom means the leech isn't hooked to windward (too tight, stalling) or fallen open (too loose, spilling). Together they're your "is the sail actually working?" gauge. And for heel: dropping the traveler spills power without changing sail shape, so it's the instant, reversible first move in a gust — reefing is the permanent one you do when the gusts become the norm.

Q18Fair-weather cumulus

Form: sun heats the land → warm air rises and cools as it climbs → at the height where it cools to its dewpoint, the moisture condenses onto dust particles → cloud. That dewpoint height is the flat cloud base.
Appear: mid-to-late morning
Look: white, fluffy, cotton-wool; flat grey bottoms; taller than they are wide
Decay: afternoon sun lowers → land cools → updraft stops → clouds dissolve
Gone by: late afternoon

Why cumulus has a daily rhythm. These clouds are made by the sun heating the ground, so they follow the sun: nothing at dawn, building through the morning as the land warms, peaking at midday, fading as the afternoon sun weakens. For a sailor that flat grey base is a free altimeter — it marks the height where rising air hits the dewpoint, the "condensation level." Tidy, separated puffs = stable, settled day. Watch them instead pile upward into towers and you're watching the start of a thunderstorm — same process, just with far more heat and moisture feeding it.

The dewpoint — and why it's the thread linking this cloud to the fog question below. Air always carries invisible water vapour, and it can only hold so much at a given temperature. The dewpoint is the temperature at which that air becomes full — cool it any further and the surplus vapour condenses into visible droplets. A cumulus cloud is that moment happening aloft: a rising parcel cools as it climbs and the instant it reaches its dewpoint, the water condenses and the cloud begins — which is why the bases are all flat and at the same height (the parcels all hit the dewpoint at the same altitude). Fog (Q20d) is the exact same event at sea level — air cooled until temperature and dewpoint coincide. Cloud aloft, fog at the surface: one principle, two altitudes. Teach them together and a student answers both questions from a single idea.

Q19Land & sea breezes

After sunset → land breeze (blows offshore): land cools faster than the water, air rises over the now-warmer lake, and cool air slides off the land to fill the gap. During a sunny day it's the reverse — a sea breeze blowing onshore.

Why the breeze flips at dusk. It's all about which surface is warmer right now. Water has enormous thermal inertia — it heats and cools slowly; land changes temperature fast. By afternoon the land is hotter, so air rises over the land and cool sea air flows in to replace it (sea breeze). After sunset the land dumps its heat quickly and the water is now the warmer surface, so the circulation reverses and air flows from land to sea (land breeze). Tie it to PEC mornings: that gentle offshore land breeze at anchor is why early starts are often glassy near shore and fill in once the sun gets to work.

Q20When does fog form — circle all correct

✓ Over land on clear, cool, near-calm summer nights (radiation fog)
✓ Warm moist air blown over cold water (advection fog)
✓ When dewpoint and temperature meet
✗ Strong cold wind over cold water
✗ Barometer rising after a temperature drop

The one principle behind all of fog: temperature meets dewpoint. Fog is simply cloud at sea level. Air can only hold so much water vapour; cool it to its dewpoint and the surplus condenses into the tiny droplets we call fog. Everything on the list is just a different way to reach the dewpoint:

Radiation fog — on a clear, calm night the ground radiates its heat to space and chills the air just above it to the dewpoint. It needs clear skies (so heat escapes) and calm (so it isn't mixed away) — that's why it's a dawn, over-land phenomenon that burns off as the sun warms the ground.
Advection fog — the sailor's fog. Warm, moist air blows over cold water (think Lake Ontario in spring), the water chills the air's underside to the dewpoint, and fog forms over open water. Because the wind keeps feeding new moist air across the cold surface, it can sit for days and won't simply burn off.

Why the two wrong answers are wrong: a strong cold wind over cold water has no warm moist air to chill and the wind mixes the layer too vigorously for fog to settle — you get clear, breezy conditions, not fog. And a rising barometer signals building high pressure, sinking dry air, and improving weather — the opposite of the moist, still set-up fog needs.

Make it local and useful. The fog that matters on our courses is advection fog — spring and early summer, a warm southerly over still-cold Lake Ontario water. Teach the tell: the air feels mild and damp and the lake feels cold. That's your cue to fix a position, set a careful pilotage plan, get the radar reflector up (Q32) and sound your fog signals before the visibility closes in — not after.

Q21aLeak — hull not damaged

Find the source and the rate
Check through-hulls, stuffing box, keel bolts, hoses, rudder post, strainer
Fix it — close the seacock or drive in a wooden plug
Start pumping / bailing
PFDs on the crew
If it keeps gaining — head for shore, shallows, or a safe harbour

Q21bFouled propeller

Stop the engine immediately
Sail clear, heave-to, or anchor
Engine in NEUTRAL before anyone goes near the prop
Pull the line by hand; try gently turning the shaft by hand in reverse
Cut it with a knife on a boat hook
If conditions allow, someone over the side with a secured knife
Otherwise make for shelter / call a tow

Q21cAground on a falling tide that will dry

Prop her upright if you can; if not, lay her down with the mast toward shore
Cushion the hull with anything available
Set anchors to seaward to hold her still
Close seacocks, ports and hatches so the rising tide can't flood her

Q21dEngine cooling water fails

Stop the engine immediately (overheating warps it fast)
Sail clear, heave-to, or anchor
After a short cool-down, try a restart
Check: through-hull, raw-water strainer, impeller, hoses, pump belt
Can't fix it — sail to port or call a tow
Or raft the dinghy alongside and use its motor

Why "stop the engine" is the first move in three of these. A fouled prop, a cooling failure, an overheat — the instinct is to keep the engine going to get home, and that's exactly what wrecks it. No cooling water = the engine cooks itself in minutes; a line on the prop = you're winding it tighter and risk bending the shaft. Stopping costs you nothing you can't recover under sail, and it preserves the option of fixing the problem. That's the whole seamanship lesson: diagnose before you power through.

Q22Inoperable rudder — 3 remedies

Steer with the sails — ease the main to bear away, ease the jib to head up
Jury-rig a rudder (paddle, floorboard, locker lid)
Tow a drogue / object astern on two lines and adjust to steer
Shift crew weight to heel her and induce a turn
Raft the tender alongside and steer with its motor

Why easing a sail turns the boat. A sailboat balances around its keel. The main is behind the pivot, so its push turns the bow away from the wind — ease it and the bow comes up into the wind (heads up); trim it and she bears away. The jib is ahead of the pivot and does the opposite. Once a student feels that the sails are a steering system, a lost rudder becomes a manageable problem instead of a panic. This is also why a well-balanced boat tracks straight with the helm let go.

Q23COB who can't help themselves — 2 methods

Bowline around the chest, onto a halyard or mainsheet tackle, and hoist
A Lifesling or similar commercial recovery system
Parbuckle — roll them up the hull on two lines run under their body
Use the dinghy as a recovery platform

The hard truth to teach. Getting back to the person is the easy half; getting a soaked, exhausted, possibly unconscious adult up the topsides is the half that defeats crews. A grown person in wet gear is a dead lift of 90+ kg up a slick hull — you cannot do it by arm strength. You need mechanical advantage: a halyard on a winch, a tackle, or the parbuckle roll. Drill the recovery, not just the approach.

Q24Fixed dock, 2 m tidal range

Long spring lines · weights to hold her alongside at high water · no breast lines · a fenderboard. Lines must cover the full range of tide without re-adjusting.

Why long lines and no breast lines. The boat has to rise and fall 2 m against a fixed dock. A breast line (straight out to the dock) is short and has no give — as the tide drops it either snaps or hangs the boat off the dock. A long spring line runs at a shallow angle, so a 2 m vertical change barely alters its length; the boat slides up and down freely while still being held fore-and-aft. The longer the line, the gentler the geometry — that's the whole trick of tidal mooring.

Q25Berth that will dry out

Make her lean toward the dock — a line from the mast to the dock if needed
Heavy weight (anchor + chain) on the dockside deck
Prop the bow up if she won't sit on her keel
Check the rigging won't snag or rub the dock as she settles

Why lean into the dock. When the water leaves, the boat has to fall one way or the other. Lean her away from the dock and she topples into open space — uncontrolled, possibly past her shrouds, taking on water when the tide returns. Lean her toward the dock and the dock itself catches and supports her at a safe, known angle. You're choosing the direction of the fall before gravity chooses for you.

Q26Anchor off the bow, stern to the dock

Drop the anchor far enough out for proper scope
Motor in, stop short of the dock
Two stern lines crossed over for stability
Snug the rode to hold the stern off the dock
Mark the anchor with a float if appropriate

Q27Recovering a fouled anchor — 3 methods

Motor directly over it, snub the rode to a cleat, motor slowly ahead to trip it
Snub it with crew weight forward, then move crew aft to rock it free
Let tide or wave action break it out
Use a trip line if you rigged one
Motor a circle around the anchor to unwind it

Q28Overnight rafting — hazards & fixes

Fouled anchors use one anchor only — from the boat with the heaviest ground tackle
Too much weight drags more scope; leave the raft if it worsens; second anchor
Fire / sinking plan a fast getaway, run your own lines back aboard, brief everyone
Hull & rig contact post a watch; fenders at rail height; offset the spreaders

Why one anchor for the whole raft. If every boat sets its own hook, the rodes wrap and tangle in the night as the raft swings, and no one can leave in a hurry. A single anchor off the boat with the biggest gear gives the raft one clean pivot and one rode to manage. And why offset the spreaders: rafted masts roll on the same swell but at slightly different rates — line the spreaders up and they'll eventually swing together and lock; stagger the boats fore-and-aft and the rigs pass clear of each other.

Q29Dinghies — true / false

T An inflatable is more stable than a hardshell of the same length
F A hardshell takes a bigger outboard than an inflatable — the inflatable usually takes more

Q30Stop the dinghy bumping the hull at night — 3

Hoist it on deck or tie it to the dock
Tie it forward on the anchor rode and pay out more (steady wind/current only)
Swing it off to the side on a boom or spinnaker pole
Raft it alongside on fenders
Haul the bow up onto the transom

Q31Towing a dinghy — 3 precautions

Painter made fast securely — ideally a bridle
Use floating line so it can't foul your prop
Shorten the painter in close quarters
Empty it and take the outboard off
Match speed and painter length to the sea state

Q32Radar reflector

Mount it as high as possible · remember wet sails can mask it · hang it in the "catch-rain" position (corner up).

Why "catch-rain," corner-up. An octahedral reflector works by bouncing radar energy straight back at the ship that sent it, but only when its internal corners present a proper right-angle to the beam. Hung flat ("collect-snow") the geometry is wrong and the echo collapses; hung point-up so it would catch rain, the corners face outward and throw back a strong return. Tie it to Section 6 — this is the gear you want aloft before the advection fog rolls in.

Q33Swimming from an anchored boat — 3 factors

Lookout stays aboard
Can you re-board easily?
Boat traffic nearby
Dangerous marine life
Currents
Underwater hazards

Q34Harbour & seamanship — true / false

F You can't legally raft at a public dock — you can, with permission
T Cross rafted boats forward of the mast
F Keeping clear of racing boats is required by the Collision Regs — it's courtesy, not law
T Near a sinking vessel, your first duty is your own boat & crew
T You may ask a boat not to anchor in your swinging room

Why "cross forward of the mast." Two reasons, both about respect and safety: the cockpit is the crew's living space — you walk across someone's foredeck, not through their dinner — and the foredeck is the wide, uncluttered, strong part of the boat, clear of the boom, backstay and cockpit gear. It's the courteous route and the safe route at once.

Q35Distress message — 6 essentials

Name of the vessel
Position
Description of the vessel
Number of people aboard
Nature of the distress
Assistance required

Teaching the Mayday. Drill the order until it's reflex — under real stress people forget the two that matter most to rescuers: position (so they can find you) and number of people (so they know when everyone's accounted for). Have them write a card and tape it by the VHF. Mayday = grave and imminent danger; Pan-Pan = urgent but not life-threatening; Sécurité = safety/navigation info.

Q36Rope types & uses

Nylon stretchy, strong, abrasion/UV resistant → dock lines, anchor rode
Polyester / Dacron low stretch, strong, great UV → halyards, sheets
Polypropylene stretchy, poor UV, floats → dinghy painter, heaving line

Why the stretch is the answer to "which rope." Pick the line by the job: a dock line or anchor rode wants stretch — nylon acts like a shock absorber, soaking up the snatch of waves and gusts so the cleats aren't torn out. A halyard or sheet hates stretch — you set the sail shape and want it to stay put, so low-stretch polyester. And a painter or heaving line must float so it stays clear of props and reaches a person in the water — that's polypropylene's one job, even though sun destroys it (so you replace it often). Match the property to the purpose and you never have to memorize the list.

One formula runs Q38–Q40. Distance = Speed × Time. Rearranged for the exam: minutes = Distance ÷ Speed × 60. Teach them to write the units every time — if "knots" and "hours" don't cancel to "nautical miles," they've set it up upside down.

Q38Distance · 5.6 kn for 30 min

5.6 × 30 ÷ 602.8 nm

Q39ETA · 18 nm at 4 kn, leave 0945

60 × 18 ÷ 4270 min = 4h 30m

0945 + 04301415

Q40Revised ETA · after 1.5 h, speed → 5 kn

Covered in 1.5 h @ 4 kn6 nm

Remaining18 − 6 = 12 nm

60 × 12 ÷ 5144 min = 2h 24m

0945 + 1:30 + 2:241339

Q41True → Compass T V M D C

True, Variation, Magnetic, Deviation, Compass. Going T → C: East errors ADD, West errors SUBTRACT ("East is least, West is best" — read it backwards going this way).

a) 049°T · var 20°E · dev 5°E049 → 029°M → 024°C

b) 175°T · var 20°E · dev 2°W175 → 155°M → 157°C

Q42Compass → True C D M V T

Reverse direction. Going C → T: East errors SUBTRACT, West errors ADD.

a) 025°C · dev 5°E · var 12°W025 → 030°M → 018°T

b) 310°C · dev 4°E · var 12°W310 → 314°M → 302°T

Why variation and deviation are two different corrections. Variation is the Earth's fault: the magnetic pole isn't the geographic pole, so the chart (true) and a perfect compass (magnetic) disagree by an amount printed on the compass rose, and it depends on where you are. Deviation is the boat's fault: the engine, the rigging and electronics pull the needle off magnetic, by an amount that depends on the heading you're on. So you correct in two steps — first the world (variation), then the boat (deviation). Teach the direction with a sentence, not a sign rule: converting from true toward compass you're undoing the corrections, so add easterly; converting from compass toward true you're applying them, so subtract easterly.

Updating variation (the step before T→C). The rose gives variation for an old year; the exam wants it for the current year. Method: (current year − chart year) × annual change, carried in minutes (60′ = 1°), then apply by sign. The official worked example: rose reads 22°E set in 2003, annual change 7′W → for a 2022 sitting that's 19 yrs × 7′ = 133′ = 2°13′W; a westerly change reduces an easterly variation, so 22°00′ − 2°13′ = 19°47′ ≈ 020°E. Run it for this exam's year — a 2026 sitting is 23 yrs × 7′ = 161′ = 2°41′, giving 22° − 2°41′ ≈ 019°E. Mind the sign: a westerly annual change subtracts from an easterly variation but adds to a westerly one (Q42's 9°W rose grows to 012°W).

End of Intermediate Cruising review · 42 questions · pass 140 / 200

Good luck on the water ⛵

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