Coastal Skipper / Yachtmaster Theory Exam Preparation

Prerequisites

RYA Day Skipper shorebased knowledge: chart symbols, position fixing, tidal heights at standard ports and course to steer.
The Coastal Skipper / Yachtmaster Offshore shorebased course, completed or in progress. This lesson is about passing its assessments, not a replacement for the course. The topics themselves are taught in Advanced Chartwork, Tidal Heights and Secondary Ports, Course Plotting and Tidal Navigation, Coastal Passage Planning, COLREGs, Traffic Separation and Restricted Visibility and Advanced Meteorology.
Plotting instruments you are comfortable with (Portland or Breton plotter, or parallel rule), dividers, 2B pencils, soft eraser and a basic non-programmable calculator.

Learning Objectives

By the end of this lesson you will be able to (RYA Coastal Skipper / Yachtmaster Offshore shorebased course, assessment):

Describe how the shorebased assessments are structured and timed (RYA: shorebased course assessment).
Work a chartwork paper accurately and quickly: fixes, EPs, course to steer and variation and deviation (RYA syllabus: position, course to steer, compass).
Solve secondary port tidal height and clearance problems without errors (RYA syllabus: tides).
Answer passage planning questions with a structured plan (RYA syllabus: passage planning).
Answer COLREGs questions on lights, shapes, sound signals and conduct precisely (RYA syllabus: IRPCS).
Interpret synoptic charts and forecasts in the meteorology questions (RYA syllabus: meteorology).
Manage your time in the exam room and avoid the common errors that cost marks.

RYA Syllabus Map

RYA syllabus item	Where it is covered
Shorebased assessment structure	How the Assessment Works
Position, the magnetic compass, course to steer, EP	The Chartwork Paper
Tides: secondary ports, clearances, tidal streams	Tidal Calculations
Passage planning, pilotage, navigational aids	The Passage Making Paper
International Regulations for Preventing Collisions at Sea	The Collision Regulations Paper
Meteorology: synoptic charts, forecasts, sources	Meteorology Questions
Exam technique	Technique and Timing, Common Errors

Formats change. Assessment structure, timings and pass criteria are set by the RYA and can be revised. The figures below reflect what RYA training centres published in 2026. Check with your training centre and on rya.org.uk before you sit the papers, especially if you need the result for commercial endorsement.

How the Assessment Works

The Coastal Skipper / Yachtmaster Offshore shorebased course runs to roughly 40 to 60 hours of teaching, classroom or online. Assessment is in two forms:

Continuous assessment and short tests during the course, typically on meteorology, COLREGs and safety, set by the instructor.
Final assessment papers. Training centres currently describe three papers:

Paper	Typical time	Content
Collision regulations (IRPCS)	About 1.5 hours	Lights, shapes, sound signals, steering and sailing rules, TSS, restricted visibility
Chartwork	About 2 hours	Fixes, EPs, course to steer, compass, tidal heights and streams on a practice chart
Passage making	About 3.5 hours	Passage planning, pilotage, tides, meteorology, safety and decision making, often built around a single scenario

Papers can usually be sat in one session or separately. They are open to chart, almanac extracts and tidal atlas supplied with the paper, but not to notes. If you want to commercially endorse a Yachtmaster certificate later, the assessment must be invigilated, so tell the centre at the start; an un-invigilated online assessment may not count.

Pass criteria are set by the RYA and applied by the centre. Marks are lost mainly for wrong answers outside tolerance, not for untidy working, but clear working lets a marker give credit for method.

Technique and Timing

Before you start writing

Read the whole paper first (5 minutes). Mark which questions use the same tidal data so you only extract it once.
Note the chart datum, the units and the time zone. Almanac times are usually UT; summer exam scenarios are usually BST (UT plus 1). Converting the wrong way is a classic loss of a whole question.
Budget your time by marks. A simple rule: minutes available divided by total marks gives minutes per mark. On a 2 hour, 60 mark chartwork paper that is 2 minutes per mark. A 10 mark course to steer gets about 20 minutes.

While working

Write the answer in the format asked: true or magnetic, nearest degree, time in BST, height to one decimal place.
Show a short line of working for every calculation. A marker can give method marks only for what they can see.
Draw neatly on the chart with standard symbols: one arrow for the water track, two for the ground track, three for the tidal stream; a circle with a dot for a fix, a triangle for an EP.
If you get stuck, write down the method, move on and come back.

Last 10 minutes

Check every answer has the units and reference (T or M) written.
Recheck the arithmetic on tidal heights: a sign error on a height difference is the most common slip.
Read each answer against the chart: is a course of 240 sensible for a passage that runs north-east? Common sense catches big errors.

The Chartwork Paper

Compass conversion

Remember the order True, Variation, Magnetic, Deviation, Compass. Going from true to compass, add westerly errors and subtract easterly ones. Going from compass to true, do the opposite.

Practice question. You need to steer 336 T. Variation is 3 W, deviation on that heading is 2 E. What compass course do you steer?

336 T plus 3 W gives 339 M. 339 M minus 2 E gives 337 C.

Fixes and EPs

A three-point fix with good angles (60 to 120 degrees between bearings) gives a small cocked hat. Take the position at the corner nearest danger, not the middle, if the hat is large.
An EP starts from your last fix and lays off the water track (heading corrected for leeway) for the distance run by log, then the tidal stream for the same time. The end of the tidal vector is the EP.
Leeway is applied downwind: on port tack in a south-westerly wind, the boat is pushed to the north-east of her heading.

Course to steer

Always work on a time basis, usually one hour.

Practice question. You want to make good a track of 000 T. The tidal stream for the next hour is 090 T at 2.0 knots. Boat speed through the water is 5.0 knots. Ignore leeway. Find the course to steer and the speed over the ground.

Lay off the 1 hour tidal vector (090, 2.0 miles) from the start. From its end, swing an arc of 5.0 miles to cut the intended track. The angle between heading and track satisfies sine angle = 2.0 divided by 5.0 = 0.4, so the angle is about 23.6 degrees. To counter an easterly set you must point west of the track: course to steer about 336 T. Speed over the ground is 5.0 times cos 23.6 = about 4.6 knots.

On paper you would measure, not calculate, but the trigonometry is a useful check on the drawing.

Multi-hour passages

For a passage longer than one hour, add up all the tidal vectors for the hours you expect to be under way, and steer a single course. Do not change heading each hour unless the paper asks for it. Work out the number of hours first from the distance and a rough speed over the ground, then refine.

Tidal Calculations

Standard port heights

Find HW and LW times and heights, work out the duration and range, and use the tidal curve. For a quick check of a curve answer, the rule of twelfths works on a regular semi-diurnal tide: in the six hours from LW to HW the tide rises 1, 2, 3, 3, 2, 1 twelfths of the range in successive hours.

Practice question. HW is 0612 at 5.2 m; LW is 1236 at 0.8 m. Estimate the height of tide at 0912.

Range = 5.2 minus 0.8 = 4.4 m. 0912 is HW plus 3 hours. After three hours the tide has fallen 1 plus 2 plus 3 = 6 twelfths, which is half the range, 2.2 m. Height = 5.2 minus 2.2 = 3.0 m. (The curve for this port may give a slightly different figure; in the exam use the curve if it is provided.)

Secondary ports

Extract the standard port HW and LW times and heights.
Interpolate the time differences for HW and LW between the values given for the standard port times either side.
Interpolate the height differences for MHWS/MHWN and MLWN/MLWS according to the day's heights.
Apply the differences, taking great care with signs.
Use the standard port curve with the secondary port times and heights. Where the almanac gives a separate curve (for example on parts of the south coast of England between Swanage and Selsey), use that method instead.

Tip. Draw the interpolation as a small sketch with the two known points and the answer marked between them. It prevents the most common sign error.

Clearance and drying heights

The relationships are simple and examiners test them repeatedly:

Depth = charted depth + height of tide.
Depth over a drying feature = height of tide minus drying height.
Clearance under a bridge = height of the bridge (above HAT on modern UK charts) + HAT minus height of tide, minus your air draught.

Practice question. A bar dries 1.2 m. Your draught is 2.0 m and you want 0.5 m under the keel. What height of tide do you need?

Required depth = 2.0 plus 0.5 = 2.5 m. Height of tide needed = 2.5 plus 1.2 = 3.7 m. Use the tidal curve to find when the tide rises through 3.7 m; that is the earliest time you can cross.

Tidal streams

Read the tidal stream atlas or tidal diamond for the right hour relative to HW at the reference port, then interpolate the rate between springs and neaps using the day's range. Mixing up the hour (HW plus 2 versus the hour starting at HW plus 2) is a frequent error: a tidal diamond hour is centred on the time given.

The Passage Making Paper

This paper usually gives a scenario: a boat, a crew, a start port, a destination and a forecast, and asks a series of linked questions. Structure every planning answer the same way so you do not miss marks:

Constraints: crew experience, boat limits, fuel and water, time available.
Tidal gates: headlands, races and harbour entrances, with the window of time when each can be passed.
Departure time that fits all the gates and daylight or night needs, worked out backwards from the most critical gate.
Route with waypoints, distances and courses, clear of dangers and traffic schemes.
Weather limits: wind strength and direction at which you would go, delay or divert.
Ports of refuge and when each is usable.
Pilotage plan for arrival: transits, clearing bearings, leading lines, depth contour, lights for a night arrival.
Safety and crew briefing, watch system for longer passages.

Examiners award marks for reasoning. "Leave at 0530 to carry the fair stream round the headland from HW Dover minus 1, arriving at the race at slack water" earns more than "leave early".

Worked practice question

A 10 m yacht averaging 6 knots through the water plans a 42 mile passage. A headland race 18 miles from the start must be rounded within one hour either side of slack water, which occurs at 1030. The fair stream along the first leg averages 1 knot.

Speed over the ground on the first leg is about 6 plus 1 = 7 knots. 18 miles takes about 2 hours 34 minutes. To arrive at 1030, leave at about 0756. To arrive at the start of the one hour window (0930), leave at 0656. A sensible plan is to leave at 0730 to arrive around 1004, giving a margin both ways, and to have a decision point off the headland: if you arrive after 1130, wait or divert.

The Collision Regulations Paper

Marks here are lost to imprecision. Learn the exact rule numbers and the exact light arcs.

Arcs and ranges: masthead 225 degrees, sidelights 112.5 degrees each, sternlight 135 degrees. Know the minimum ranges by vessel length (a vessel of 50 m or more: masthead 6 miles, others 3 miles).
Rules 12 to 18: sailing vessels, overtaking, head-on, crossing, give-way and stand-on, and the order of responsibilities.
Rule 10: crossing a TSS on a heading as near as practicable at right angles to the general direction of traffic flow.
Rule 19: in restricted visibility there is no stand-on vessel; avoid altering to port for a vessel forward of the beam (other than one being overtaken), and avoid altering towards a vessel abeam or abaft the beam.
Sound signals: one prolonged at intervals of not more than 2 minutes for a power-driven vessel making way in restricted visibility; one prolonged and two short for a sailing vessel, a vessel not under command and several others.

Practice question. At night you see, fine on your starboard bow, a white light over a white light with a red light below and slightly forward. What is it, and what do you do?

Two white masthead lights indicate a power-driven vessel of 50 m or more. Seeing her red sidelight means you are looking at her port side, so she is crossing from your starboard side towards your port side. If you are a power-driven vessel she is on your starboard side, so you are the give-way vessel under Rule 15: take early and substantial action, normally an alteration to starboard to pass astern of her, and avoid crossing ahead (Rules 15 and 16). If you are under sail, she should keep out of your way under Rule 18, but you must monitor her compass bearing and act under Rule 17 if she does not.

Answer these questions in full sentences that name the rule.

Meteorology Questions

Expect to:

Identify fronts, highs, lows, isobar spacing and wind direction on a synoptic chart, and say how the wind will change as a depression passes (veering and increasing ahead of a warm front, then veering again at the cold front, with squalls).
Interpret the shipping forecast and inshore waters forecast terms: "soon" means within 6 to 12 hours, "later" more than 12 hours, "imminent" within 6 hours. A gale warning means mean winds of Beaufort force 8 or gusts of 43 to 51 knots.
Explain sea breezes, fog types (advection fog over cold water with a warm moist airstream; radiation fog over land on clear still nights) and wind against tide effects.
Name reliable sources: Met Office shipping and inshore forecasts, Navtex, coastguard broadcasts on VHF, GRIB files with their limitations.

Practice question. A depression is moving east, its centre passing north of you. Describe the wind changes you expect.

Ahead of the warm front the wind backs and increases from the south or south-east with lowering cloud and rain. At the warm front it veers south-west and visibility can be poor in drizzle. At the cold front it veers sharply west or north-west with heavy showers and squalls, then pressure rises and visibility improves.

Worked Example

Tom's mock chartwork paper, marked. Tom scored 58 per cent on a mock. His tutor's marking shows:

Question	Marks lost	Cause
Secondary port height	6 of 10	Applied a minus 0.3 m height difference as plus 0.3 m
Course to steer	4 of 12	Gave answer in true when magnetic was asked
EP	3 of 8	Applied leeway to windward
Time of HW	5 of 5	Used UT, not BST
Fix	0	Correct

Every lost mark came from process errors, not lack of knowledge. Tom builds a one-line checklist he writes at the top of each paper: "BST? T or M? Signs? Leeway downwind?" On the next mock he scores 86 per cent. The lesson is that most candidates who fail the chartwork have the knowledge but not the discipline.

Common Errors

Time zones: forgetting to add an hour for BST, or adding it twice.
Signs on tidal differences: the commonest single error on secondary port questions.
True or magnetic: answering in the wrong one, or not stating which.
Leeway the wrong way: always downwind of the heading.
Wrong tidal hour: tidal stream data applied to the wrong hour relative to HW.
Measuring distance on the wrong scale: always use the latitude scale level with the work, never the longitude scale.
Vague COLREGs answers: "give way" without saying how, or wrong rule numbers.
Planning without reasoning: listing waypoints without explaining why the departure time works.
Running out of time: spending 40 minutes on a 6 mark question.

Summary

Training centres currently describe three final papers: collision regulations (about 1.5 hours), chartwork (about 2 hours) and passage making (about 3.5 hours), plus in-course tests. Check current formats with your centre and rya.org.uk.
Invigilation is needed if you will later commercially endorse a Yachtmaster certificate.
Read the whole paper, budget time by marks, and write units and references on every answer.
In chartwork, the errors are usually process errors: time zone, signs, true or magnetic, leeway direction.
For tides, use depth = charted depth plus height of tide, and height needed = draught plus clearance plus drying height.
In passage making, answer with a structure and give the reasons.
In COLREGs, quote the rule and be exact.

Check Your Understanding

You need to steer 095 T. Variation is 4 W, deviation 1 W. What is the compass course?

Answer: 095 T plus 4 W = 099 M; 099 M plus 1 W = 100 C.

Charted depth is 0.8 m and height of tide is 2.6 m. What is the depth of water?

Answer: 0.8 plus 2.6 = 3.4 m.

A rock dries 2.1 m. Your draught is 1.8 m and you want 0.4 m clearance. What height of tide do you need?

Answer: 1.8 plus 0.4 plus 2.1 = 4.3 m.

On port tack in a north-westerly wind, which way does leeway push the boat relative to her heading?

Answer: To the south-east, that is downwind of her heading.

Why must the theory assessment be invigilated for some candidates?

Answer: An invigilated assessment is required if the Yachtmaster certificate will later be commercially endorsed.

In restricted visibility, a vessel is detected by radar forward of your beam and is not being overtaken. Which way should you avoid altering course?

Answer: To port (Rule 19 (d)).

In a shipping forecast, what does "later" mean?

Answer: More than 12 hours from the time of issue.

Name three process checks that prevent most lost marks in the chartwork paper.

Answer: Any three of: correct time zone (BST or UT), correct signs on tidal differences, answer in true or magnetic as asked, leeway applied downwind, correct tidal hour, latitude scale for distance.