The Day Skipper Cheat Sheet

Shape of the assessment

Paper	Time	Content
1 · General	90 min	Short written answers: IRPCS, buoyage, lights and shapes, sound signals, weather, safety, ropes, anchoring, terms, electronics, passage planning.
2 · Chartwork	90 min	Plotting on RYA training charts: positions, fixes, EP, course to steer, tidal heights and streams, pilotage, passage.

Taken at home or in the classroom under exam conditions. Allowed: RYA Training Almanac and RYA Training Charts 3 & 4, plotter, dividers, pencil, calculator. Not allowed: course notes or handbook. The pass is understanding, not perfection — working shown earns marks when the final number slips.

The seven recurring mark-losers

Slip	Guard
Bearing with no suffix	Always three figures + T / M / C: 045°T, never 45.
Variation applied the wrong way	Draw the ladder every time. CADET going up, subtract East going down.
Deviation from a bearing	Deviation is looked up by ship's heading, never by the bearing of an object.
Depth vs height of tide	Charted depth is below chart datum baseline; height of tide is added to it. Drying heights (underlined) are subtracted.
CTS and EP drawn the same	EP: DR first, then tide. CTS: tide first, then the boat-speed arc.
Times in the wrong zone	Note UT vs BST at the top of the page and add the hour once, in writing.
Reading the question thinly	Underline what is asked: a time, a height, a bearing, a course, or a decision. Answer that, with units.

Reading a position

Latitude first, then longitude, degrees and decimal minutes, with the hemisphere: 50°42.35'N 001°18.60'W. Latitude is read on the side of the chart, longitude on the top and bottom.

Quantity	Rule
Distance	1 nautical mile = 1 minute of latitude. Measure on the side scale, at the latitude of your work.
Never	Measure distance on the longitude scale — minutes of longitude shrink towards the poles.
Cable	0.1 nm ≈ 185 m. "Two cables off" = 0.2 nm.
Knot	1 nm per hour. Distance = Speed × Time.
Depth / height	Metres on modern charts; check the chart's units note in the title block.

Chart datums, in one line each

5₈	Charted depth 5.8 m — least depth expected, measured above chart datum.
1₅	Drying height 1.5 m — dries that much above chart datum. Underlined.
(12)	Charted height of a light, bridge or land — above MHWS.
┄┄	Depth contour; the 5 m and 10 m contours make good pilotage handrails.

Symbols worth knowing cold

On the chart	Means
Magenta anything	Caution or man-made: lights, buoys, cables, prohibited areas.
Star + magenta flare	Lighthouse, with its character alongside.
Diamond with letter	Tidal diamond — look the letter up in the chart's tidal stream table.
Circled dot ⊙	Tide-rip, overfalls or observation spot depending on annotation.
Anchor symbol	Anchorage. Crossed-out anchor = anchoring prohibited.
Wreck symbols	Hull outline = shallow/dangerous wreck; ⊕ with dots = depth known; dotted circle = position approximate.
S, M, Sh, R, Co	Seabed: sand, mud, shingle, rock, coral — anchoring quality.
Green tint	Dries at LAT — the drying foreshore.
Blue tint	Shallow water, usually inside the 5 m or 10 m line.

Publications and their job

Almanac	Tide tables, tidal curves, port entry, lights, radio, safety.
Pilot book	Prose description of harbours, approaches, hazards, photos.
Chart 5011	The dictionary of chart symbols and abbreviations.
Notices to Mariners	Corrections; the chart is only as good as its last correction date (bottom left).

What each one is

True	Geographic north. What the chart is drawn to, what you plot.
Magnetic	True corrected for variation — where the earth's field points at that place and year.
Compass	Magnetic corrected for deviation — what your boat's own iron does to the needle, on that heading.

Deviation, the trap

• Caused by the boat's own magnetic fields: engine, keel bolts, speakers, a phone left on the bulkhead.
• It changes with the boat's heading, so it is read off a deviation card against the ship's heading.
• It is never looked up against the bearing of a lighthouse. A hand-bearing compass taken well away from steelwork is treated as deviation-free.
• Checked by a transit: compare the compass bearing of two objects in line with the charted (magnetic) bearing.

Wrapping and format

• Three figures always: 007°, not 7°.
• Wrap within 000–359: 358 + 5 = 003, 002 − 5 = 357.
• Suffix always: T (true), M (magnetic), C (compass).
• Reciprocal = ± 180°. A light bearing 210° from you means you bear 030° from it.

Drill this: Three Norths →

The three plotting symbols

Symbol	Line	Meaning
→	One arrow	Ground track / course over the ground — what actually happens.
→→	Two arrows	Water track — the course you steer through the water.
→→→	Three arrows	Tidal stream — set (direction it goes towards) and drift (distance).
⊕ 1030	Circle + dot	Fix, with time in four figures.
△ 1130	Triangle	Estimated position, with time.
•	Dot / tick	DR position — course and log only, no tide.

Fixing your position

1. Pick three objects roughly 60° apart, charted and certainly identified.
2. Take the quickest-changing bearing last (the one nearest the beam), note the time and log.
3. Convert each: compass → magnetic → true. Write each line out.
4. Plot from the object with the reciprocal; label each line with its bearing.
5. A small cocked hat is normal; take the position at the corner nearest the danger.

Other good fixes: a transit (two objects in line — the most accurate line on any chart, no compass involved), a transit crossed with a bearing, a bearing crossed with a depth contour, a range from a radar or a rising/dipping light.

Estimated position — "where am I?"

1. Start at the last fix. Plot the water track (course steered, corrected to true, plus leeway) and step off the log distance run — that end is the DR.
2. From the DR, plot the tidal stream for the same period: set and drift, three arrows.
3. The end of the tide vector is your EP. Triangle, time it.
4. The line fix→EP is your ground track; measure it for course and distance made good.

Course to steer — "where do I point?"

1. Draw the ground track you want: a line from your position to the destination. Don't measure it yet.
2. From your position, plot the tidal stream for one hour (set and drift). Call its end A.
3. From A, swing the dividers at your boat speed through the water for one hour; where the arc cuts the ground-track line is B.
4. A→B is the course to steer (water track, two arrows). Measure it: that's your heading in true.
5. Apply leeway: steer upwind of that by the leeway angle. Then apply variation and deviation down the ladder to get °C.
6. Your position→B is the ground track: measure it for speed over the ground and the ETA.

Multi-hour legs: use whole hours of tide from the same starting line — two hours of tide then a two-hour boat-speed arc. The construction is identical, the numbers just double.

The vertical picture

You want	Sum
Depth of water now	charted depth + height of tide
Depth over a drying patch	height of tide − drying height
Clearance under the keel	depth of water − draught
Clearance under a bridge	charted height + MHWS − height of tide
Range of the tide	HW height − LW height

Springs and neaps

• Springs: new and full moon, sun and moon in line. Biggest range, highest HW, lowest LW, fastest streams. About two days after the moon phase.
• Neaps: first and last quarter. Smallest range, weakest streams.
• Roughly fortnightly cycle; the almanac prints the spring/neap ranges for each standard port in the curve panel.

Standard port, height at a given time

1. Find the day's HW and LW times and heights. Correct for BST (+1 h) if the tables are UT and the question is local.
2. Compute the range = HW − LW, and see where it sits between the printed spring and neap ranges.
3. On the tidal curve, mark HW height on the top scale and LW height on the bottom scale; join them with a sloping line.
4. Enter the time scale at HW, count the hours to the time you want, go up to the curve — spring curve solid, neap curve dashed, interpolate for anything between.
5. Go across to the sloping line, then up or down to the height scale. Read the height of tide.

Time for a given height — the same picture backwards

Enter on the height scale, across to the sloping line, up to the curve, down to the time scale, and add or subtract from HW. Two answers exist each tide (one rising, one falling) — say which you mean.

Secondary ports

1. Work the standard port tide for the day, first.
2. Take the secondary port's time differences (given for HW at e.g. 0000 and 0600) and interpolate for your actual HW time.
3. Take the height differences for MHWS / MHWN / MLWN / MLWS and interpolate for your actual HW and LW heights.
4. Apply both: secondary HW time and height, secondary LW time and height.
5. Use the standard port's curve with the secondary port's figures unless the almanac prints its own.

Day Skipper needs awareness and a straightforward case; Coastal/Yachtmaster needs full interpolation. Lay the work out as a table — standard, difference, secondary — and the marks follow the layout.

Two sources, same answer

Source	How to read it
Tidal diamond on the chart	Find the lettered diamond nearest your track, then the table: rows are hours before and after HW at the named standard port, columns give direction (°T), spring rate, neap rate.
Tidal stream atlas	One page per hour relative to HW. Arrows show direction; figures like 19,34 mean 1.9 kn neaps, 3.4 kn springs — the comma is a decimal point, small number first.

Interpolating for the day

1. Work the standard port's HW time for the day and label your hours: HW−3, HW−2, … HW+1.
2. Work the day's range and compare with the printed spring and neap ranges.
3. Interpolate the rate between the neap and spring columns in that proportion. Halfway between = the mean of the two.
4. Multiply by the hours you'll be in that square to get drift.

Computation aid in the almanac does this graphically; in the exam, plain proportion is accepted if you show it.

Using the stream, not fighting it

• Tidal gate: a headland or narrows where the stream runs hard — plan to arrive with it, not against it.
• A fair tide of 2 kn on a 5 kn boat is a 40% speed change; over a day it dwarfs any sail trim.
• Streams turn earlier inshore and run harder off headlands and over shoals.
• Wind over tide = short, steep, breaking seas. Same strength, far worse ride.
• In a river or narrow channel, the stream follows the deep water; the eddy at the edge may run the other way.

Lateral marks — Region A (UK and Europe)

Mark	Day	Light
Port	Red can, can topmark	Fl R / Q R / any red rhythm
Starboard	Green cone, point up	Fl G / Q G
Preferred channel to starboard	Red with one broad green band, can	Fl(2+1) R
Preferred channel to port	Green with one broad red band, cone	Fl(2+1) G

Cardinal marks — go where the black points

Mark	Topmark (2 cones)	Body	Light (white)
North	Both points up	Black over yellow	Q or VQ (continuous)
East	Base to base (♦)	Black, yellow band, black	Q(3) 10s / VQ(3) 5s
South	Both points down	Yellow over black	Q(6)+LFl 15s / VQ(6)+LFl 10s
West	Point to point (wine glass)	Yellow, black band, yellow	Q(9) 15s / VQ(9) 10s

The other four marks

Mark	Day	Light	Means
Isolated danger	Black with red band(s), two black balls	Fl(2) white	Small danger with navigable water all round — stay off.
Safe water	Red and white vertical stripes, single red sphere	Iso, Oc, LFl 10s or Mo(A)	Mid-channel or landfall; water all round.
Special	Yellow, yellow X topmark	Fl Y	Not navigational: spoil ground, outfall, racing buoy, cable.
Emergency wreck	Blue and yellow vertical stripes, yellow cross	Al Oc Bu/Y 3s	New, uncharted wreck. Alternating blue/yellow.

Light characters, decoded

Abbr.	Name	Rhythm
F	Fixed	Continuous, steady.
Fl	Flashing	Light shorter than dark. Fl(3) 10s = three flashes every 10 s.
LFl	Long flashing	One flash of 2 s or more.
Q	Quick	50–60 flashes a minute.
VQ	Very quick	100–120 a minute.
IQ / IVQ	Interrupted	Quick flashing with a regular dark gap.
Iso	Isophase	Equal light and dark.
Oc	Occulting	Light longer than dark — a "blink" of darkness.
Mo(A)	Morse	The letter in morse: A = • —, safe water / landfall.
Al	Alternating	Changes colour.

The arcs, first

Light	Arc	Where
Masthead (steaming)	225°	White, ahead to 22.5° abaft each beam.
Sidelights	112.5° each	Red port, green starboard, ahead to 22.5° abaft that beam.
Sternlight	135°	White, astern — fills the gap the masthead leaves.
All-round	360°	Anchor lights, and every "status" light (red/green/white pairs).

225 + 135 = 360: the masthead and stern arcs together cover the horizon, and each sidelight covers half the masthead arc.

Power-driven vessel underway

• Under 50 m: one masthead light, sidelights, sternlight (a second, higher masthead light is optional).
• 50 m and over: two masthead lights, the after one higher, plus sidelights and sternlight.
• Two masthead lights in line tell you the heading: open to the right, she is crossing right to left… read them with the sidelight.
• Under 12 m: may show one all-round white plus sidelights. Under 7 m and under 7 kn: one all-round white, sidelights if practicable.

Sailing vessel

• Sidelights + sternlight. No masthead light — that is the giveaway.
• Optional: two all-round lights at the masthead, red over green ("red over green, sailing machine"), with the sidelights and sternlight still burning.
• Under 20 m may combine sidelights and sternlight in one tricolour at the masthead — used instead of, never as well as.
• Motor-sailing = a power-driven vessel: masthead light on, and by day a cone, point down, forward.
• Under oars, or sail under 7 m: at least a torch or lantern shown in time to prevent collision.

Status lights and day shapes

Vessel	Lights (all-round)	Shapes
Not under command	Red over red	Two balls
Restricted in ability to manoeuvre	Red, white, red	Ball, diamond, ball
Constrained by draught	Three red in a vertical line	Cylinder
Trawling	Green over white	Two cones, points together
Fishing (not trawling)	Red over white	Two cones, points together (+ cone pointing at outlying gear over 150 m)
Pilot on duty	White over red	Flag H if displayed
At anchor	One all-round white forward (two if ≥50 m, forward one higher; deck lights on if ≥100 m)	One ball forward
Aground	Anchor light(s) plus two red	Three balls
Minesweeping	Three green: masthead and each yardarm	Three balls, same positions
Motor-sailing	As power-driven	Cone, point down
Diving	—	Rigid replica of flag A

Towing and pushing

• Tug: two masthead lights in a vertical line; three if the tow measures more than 200 m from tug stern to tow stern. Sidelights, sternlight, and a yellow towing light above the sternlight.
• Vessel towed: sidelights and sternlight only — dark between tug and tow, so never cut through.
• Tow over 200 m: a diamond shape by day on tug and tow.
• Unable to deviate from her course (tug and tow restricted): she may also show the RAM lights and shapes.

Drill this in 3D: Night Watch →

The rules Day Skipper examines by number

No.	Rule	What it demands
5	Look-out	A proper look-out by sight and hearing and all available means, at all times.
6	Safe speed	Able to stop in the distance appropriate to the visibility, traffic, manoeuvrability, background lights, sea state, draught.
7	Risk of collision	Use all available means; assume risk exists if in doubt. A constant compass bearing with decreasing range means collision.
8	Action to avoid	Early, substantial, obvious — large enough to be seen by eye or radar. Avoid a succession of small alterations. Slowing or stopping is a legitimate action. Alter course rather than speed if there is room.
9	Narrow channels	Keep to the starboard side. Vessels under 20 m, sailing vessels and fishing vessels shall not impede a vessel that can navigate only within the channel. Don't cross so as to impede. Sound one prolonged blast at a blind bend.
10	Traffic separation	Join and leave at the ends, or at a small angle. Crossing: head as nearly as practicable at right angles to the flow (heading, not track). Under 20 m, sailing and fishing shall not impede lane traffic. Use inshore zones if under 20 m or sailing.

Steering and sailing — who gives way

No.	Situation	Action
12	Sail meets sail	Different tacks: port tack gives way. Same tack: windward gives way. In doubt about the other's tack when you are on port: assume you must give way.
13	Overtaking	Coming up from more than 22.5° abaft the beam (you'd see only her sternlight). The overtaker keeps clear, sail or power, and stays clear until finally past and clear.
14	Power head-on	Both alter to starboard and pass port to port. In doubt, assume it applies.
15	Power crossing	The vessel that has the other on her own starboard side gives way, and shall avoid crossing ahead.
16	Give-way vessel	Take early and substantial action to keep well clear.
17	Stand-on vessel	Keep course and speed. You may act when it becomes clear the other is not; you must act when collision cannot be avoided by her action alone. If power, do not alter to port for a vessel on your own port side.
18	Responsibilities	The pecking order below — and remember a sailing vessel keeps clear of a vessel constrained by draught, fishing, RAM or NUC.
19	Restricted visibility	See the box opposite — no vessel is "stand-on" in fog.

Deciding in four moves

1. Is there risk of collision? Take a compass bearing. Steady bearing, closing range → yes.
2. What is she? Read lights, shapes or aspect. Power, sail, fishing, restricted?
3. Which rule? Overtaking (13) beats crossing (15) beats the sail rules (12), and Rule 18 sits over all of them.
4. Give way or stand on? If give-way: alter early, large, to starboard where possible, pass astern, and make it obvious. If stand-on: hold course and speed, keep watching, be ready to act.

Drill this: Rules of the Road →

The units

Short blast ≈ 1 second. Prolonged blast = 4–6 seconds. Written • and —.

Rule 34 — manoeuvring, in sight of one another

Signal	Means
•	I am altering my course to starboard.
• •	I am altering my course to port.
• • •	I am operating astern propulsion.
• • • • •	(at least five, rapid) I do not understand your intentions / your action is insufficient. The doubt or "wake-up" signal.
— — •	I intend to overtake you on your starboard side (narrow channel).
— — • •	I intend to overtake you on your port side.
— • — •	Overtaking agreed (Morse C).
—	Approaching a blind bend or an obstructed view in a channel — answered by the same from the other side.
—	Also: leaving a berth / getting under way where sight is obscured.

Rule 35 — in or near restricted visibility

Vessel	Signal	Interval
Power-driven, making way	—	≤ 2 min
Power-driven, underway but stopped	— —	≤ 2 min
Sailing · fishing · NUC · RAM · CBD · towing or pushing	— • •	≤ 2 min
Vessel towed (last of the tow, if manned)	— • • •	≤ 2 min
At anchor	Bell rung rapidly 5 s (plus gong aft if ≥ 100 m)	≤ 1 min
At anchor, warning an approaching vessel	• — •	as needed
Aground	3 separate bell strokes, the 5 s bell, 3 strokes	≤ 1 min
Pilot vessel on duty (extra)	• • • •	—
Under 12 m	Any efficient sound signal	≤ 2 min

Distress signals you may be asked to list

• Mayday by VHF voice on Ch 16; DSC alert on Ch 70; EPIRB; SART.
• Continuous sounding of any fog-signalling apparatus.
• Red parachute rocket or red hand flare; orange smoke by day.
• SOS by any means; the spoken word "Mayday".
• Flag N over C; a square flag with a ball above or below it.
• Slow, repeated raising and lowering of outstretched arms.
• Flames on the vessel; a gun fired at one-minute intervals.

A white flare is not a distress signal — it is an anti-collision signal to say "I am here".

Shipping forecast vocabulary

Term	Means
Imminent	Within 6 hours of the time of issue.
Soon	6 to 12 hours.
Later	More than 12 hours.
Veering	Wind direction changing clockwise (SW → W → NW).
Backing	Changing anticlockwise (SW → S → SE).
Gale warning	Force 8, or gusts 43–51 kn.
Severe gale / Storm	Force 9 (gusts 52–60) / Force 10 (gusts 61–68).
Violent storm / Hurricane force	Force 11 (gusts 69+) / Force 12.

Visibility	Range
Good	more than 5 nm
Moderate	2 – 5 nm
Poor	1000 m – 2 nm
Fog	less than 1000 m

Pressure tendency	Change in 3 h
Steady	< 0.1 mb
Rising / falling slowly	0.1 – 1.5 mb
Rising / falling	1.6 – 3.5 mb
Rising / falling quickly	3.6 – 6.0 mb
Very rapidly	more than 6.0 mb

Beaufort, the numbers that matter

F	Knots	Name / at sea
0–1	0–3	Calm / light air, mirror or ripples.
2–3	4–10	Light breeze / gentle breeze; crests begin to break.
4	11–16	Moderate; frequent white horses. Reef point for many cruisers.
5	17–21	Fresh; moderate waves, many white horses.
6	22–27	Strong; large waves, spray. "Yachtsman's gale".
7	28–33	Near gale; foam blown in streaks.
8	34–40	Gale; moderately high waves, well-marked streaks.
9–10	41–55	Severe gale / storm; visibility affected, tumbling crests.
11–12	56+	Violent storm / hurricane force.

Pressure systems in the northern hemisphere

	Low (depression)	High (anticyclone)
Circulation	Anticlockwise, spiralling in	Clockwise, spiralling out
Weather	Cloud, rain, wind, fronts, changeable	Settled, light winds, haze or fog, can be persistent
Isobars	Close = strong wind	Widely spaced = light

A depression passing over you

Stage	Sky	Wind	Pressure
Ahead	Cirrus thickening to cirrostratus, halo	Backs, freshens	Falling
Warm front	Nimbostratus, steady rain, poor visibility	Veers as it passes	Falling, then steady
Warm sector	Stratus, drizzle, mild, often murky	Steady direction	Steady
Cold front	Cumulonimbus, squalls, heavy showers, then clearing	Veers sharply, gusty	Rising
Behind	Cumulus, bright, good visibility, showers	Gusty, veered	Rising

Wind veers at every front passage in the northern hemisphere — that is the single most testable fact here. An occlusion is a cold front catching a warm one: the warm sector lifted clear of the surface, mixed weather, wind veering.

Local effects

• Sea breeze: sunny afternoon, land heats, air rises, cool air draws in from the sea. Onshore, building through the afternoon, dying at dusk; can add 10–15 kn and back or veer the gradient wind.
• Land breeze: night and early morning, weaker, offshore.
• Advection fog (sea fog): warm moist air over a cold sea. Common in spring, persists in wind — the fog that matters to sailors.
• Radiation fog: clear calm night over land, drifts out of river mouths at dawn, burns off with the sun.
• Wind over tide: steep breaking seas. Wind against a headland or shoal: overfalls and a race.
• Katabatic wind: cold air pouring down a valley or off high ground at night, gusty, offshore.
• Wind funnels and accelerates between headlands and along cliffs; expect more than the forecast in a gap.

Where the forecast comes from

Shipping forecast (BBC R4 long wave, four times daily) · inshore waters forecast · Met Office and other websites and apps · Maritime Safety Information broadcasts by the Coastguard on VHF after an announcement on Ch 16 · Navtex (518 kHz) · harbour offices and marinas · barometer and your own eyes.

The Mayday call, word for word

Call	Use
Mayday	Grave and imminent danger to a vessel or person, immediate assistance required.
Pan-Pan	Urgency: a serious problem, but no immediate danger to life — engine failure in a shipping lane, a serious injury.
Sécurité	Safety: navigational or weather information, e.g. a container adrift.
Mayday relay	You are passing on someone else's Mayday.
Seelonce Mayday	Silence imposed by the controlling station; Seelonce Feenee ends it.

Flares and what they are for

Type	Range / use
Red parachute	Up to ~25–30 nm at night, fires to ~300 m. Long-range distress — use when there is a chance of being seen.
Red handheld	~5–10 nm. Pinpoints you for a searching craft. Hold downwind, over the side.
Orange smoke	Daylight distress, ~3 nm, and shows the wind to a helicopter.
White handheld	Not distress. Anti-collision: "I am here".

Man overboard, in order

1. Shout "man overboard" and detail one person to point and never look away.
2. Press MOB on the GPS or plotter.
3. Throw buoyancy: horseshoe, danbuoy, lifesling — immediately, even if you sail back.
4. Get the crew on deck; start the engine (watch for lines in the water).
5. Manoeuvre back: a reach away and a reach back, or a crash stop, depending on boat and conditions — the plan you have practised.
6. Approach slowly from downwind, stop with the casualty at the shrouds, secure them to the boat before anything else.
7. Recover with a strop, halyard and winch — lifting horizontally where possible after a long immersion.
8. If not recovered quickly, send a Mayday. Treat for hypothermia and shock.

Kit, checks and fire

Item	Point
Lifejackets	150 N for coastal cruising; crotch strap, light, whistle, spray hood. Check gas bottle and firing head, service annually.
Harness and tether	Clip to jackstays or a strong point, not the guardrail. Short tether on deck beats a long one.
Liferaft	Serviced, lashed where it can be launched, painter made fast to the boat. Step up into the raft — abandon only when the boat is definitely going down.
Fire: prevention	Turn gas off at the bottle, sniff the bilge before starting, no smoking near fuel, secure the cooker.
Fire: action	Cut the fuel or gas, cut the air, then cool. Dry powder for most; never water on fuel or electrics. A fire blanket for a galley pan.
Bilge and pumps	Know where the seacocks are and keep bungs beside them.
Helicopter	Brief the crew, drop sails or motor as instructed, all lifejackets on. Never make the hi-line fast — let it touch the sea or the deck first to discharge static, and pay it out freely.
Before leaving	Tell someone ashore your plan and your ETA, and tell them when you arrive.

The four stages

Appraisal	Gather everything: charts, almanac, pilot book, forecast, crew and boat capability.
Planning	Write the plan: route, waypoints, tidal windows, ETA, bolt-holes, pilotage notes.
Execution	Depart at the planned time, or re-plan. The plan serves the day, not the other way round.
Monitoring	Fix regularly, log it, compare with the plan, adjust. Cross-check the plotter against a bearing or a depth.

What a Day Skipper plan must contain

• Tides: HW and LW times and heights at departure, destination and any gate; stream directions along the route hour by hour; the height of tide over every shallow patch on the way.
• Weather: the latest forecast and where the next one comes from; wind against tide spots; the limit you'll turn back at.
• Route: courses and distances leg by leg, with the expected SOG and a running ETA.
• Hazards: rocks, races, firing ranges, TSS, ferry routes, restricted areas; clearing bearings or contours for each.
• Pilotage: entry and exit plans at both ends, drawn out, with lights and marks in sequence.
• Contingency: alternative ports and the conditions under which you'd use them; where you can anchor and wait for the tide.
• Admin: fuel, water, food, crew fitness and watches, safety briefing, someone ashore told the plan.

Tidal window, worked in three lines

1. Least charted depth on the route, minus your draught and safety margin, gives the height of tide you need.
2. Read the curve for the times that height occurs, rising and falling — that's the window.
3. Check the stream and the harbour's own restrictions inside that window, then set the departure time by working back from the far end.

Pilotage — navigation without plotting

Tool	Use
Transit	Two charted objects in line: the most accurate position line there is, and it needs no compass. Also shows cross-tide instantly — if the back mark drifts left, you are being set right.
Leading line	A purpose-built transit into a harbour; keep them in line and stay in the channel.
Clearing bearing	"Keep the bearing of the church more than 060° and you stay clear of the ledge." Written NLT 060°M / NMT 145°M.
Depth contour	A handrail: follow the 10 m line, or use "not less than 5 m" as a safety line.
Sectored light	White = safe approach; red and green mark the danger sides. "Am I still in the white?"
Buoy hopping	List the marks in order with their characters and the course between each — a ladder you tick off.

Electronic navigation, and its limits

Instrument	Reads	Watch out
GPS / plotter	COG and SOG — over the ground, with the tide already in them	No tide vector to apply; position to WGS84; check the chart's datum note. Antenna and power can fail.
Compass	Heading — where the bow points	Not the same as COG whenever there is tide or leeway.
Log	STW — speed through the water	Impeller fouls; calibration drifts.
Echo sounder	Depth below the transducer, unless offset	Know whether it reads from the waterline, the keel or the transducer. Say which when you answer.
AIS	Other vessels' identity, course, speed, CPA	Not every vessel carries it. It is not a look-out.