In short
A nautical mile is 1852 metres, and what counts is the distance actually sailed, not the straight line between ports.
Distance is half of it: schemes also want days at sea, days as skipper and night hours under way.
Your role decides a great deal. Crew miles and skipper miles sit on different lines of the requirements.
Miles are signed off by the passage skipper or stamped by a school. Unconfirmed, an entry is only your word.
Orders of magnitude: about 200 miles for the first skipper rung, 800 for coastal Yachtmaster, 2500 to 3000 for offshore.
Figures differ between IYT, ISSA and RYA and are revised — check the current rules of your own body.
What counts as a mile
A nautical mile is 1852 metres, and every certificate requirement is written in them.
What counts is the distance the boat genuinely covered. If the rhumb line between two ports is 20 miles and you beat 35 to get there, you record 35. Those miles were sailed.
The second condition is that you were crew and took part in running the boat. Miles are made under way, at sea. IYT defines "at sea" as being outside any harbour, natural or artificial, where a cruising yacht could lie for a prolonged period. Anchor time falls outside that.
What generally does not count
Days alongside and at anchor, even if you slept aboard.
Passages on which you were a passenger and stood no watch.
Hour-long jaunts: some bodies state plainly that miles must come from genuine passages.
With the RYA, part of the requirement is tied to tidal waters and vessel size: half the qualifying time must be tidal and on vessels under 24 metres.
The wording varies, and in borderline cases the answer comes from your organisation, not a forum.
Which roles the miles count in
Requirements almost always come in pairs: a total, plus a separate line about command.
Crew. Ordinary miles and days at sea. The foundation of any record.
Watch leader. You run the boat while the skipper sleeps. Many schemes treat this as equivalent to skippering when counting days.
Skipper. You take the decisions and answer for the vessel and the people aboard. The scarcest line in a beginner's logbook.
So the RYA asks Yachtmaster Offshore candidates not merely for 50 days at sea but for 5 days as skipper and five passages over 60 miles, two in command. ISSA asks Offshore Skipper candidates for 28 days specifically as skipper or watch leader. IYT asks Yachtmaster Coastal candidates for 25 days and 800 miles, including 2 as watch leader or skipper.
The practical conclusion: as soon as your experience allows, ask for watches of your own and record them on a separate line.
Who confirms the miles
Checking is done by the school when you apply and by the examiner on the day. Confirming is done by those who were aboard.
The skipper of the passage. A signature in the logbook beside the entry — the commonest route. Note the name, certificate number and contact details: a couple of years may pass before you apply.
A school or instructor. Miles sailed on a course are stamped by the school. With IYT the school principal signs the passport.
The owner or delivery skipper. For deliveries and private trips this works like a skipper's signature.
A race organiser. Racing miles are confirmed by the event paperwork: entry, finish list, a line in the ship's log.
Nobody audits every line, but an examiner may ask about any passage on the list, and generally does. Someone who sailed those miles remembers the port, the weather and what broke; someone who wrote them in does not.
How many miles each rung asks for
These are the benchmarks at the time of writing. IYT, ISSA and RYA word their requirements differently, revise them periodically, and vary them according to whether you arrive from scratch or with the previous rung in hand. Check your organisation's current rules before applying.
IYT
International Bareboat Skipper — 200 nautical miles and 10 days at sea by the end of the course, from age 16.
Yachtmaster Coastal — 800 miles and 25 days at sea, of which 2 days as watch leader or skipper, plus 12 hours on watch at night under way; from age 18.
Yachtmaster Offshore — 3000 miles, at least 2000 on coastal passages, 50 days at sea and 30 hours of night watches, including 6 as captain or watch leader.
RYA
Day Skipper practical course — entry asks for 5 days on board, 100 miles and 4 night hours.
Yachtmaster Coastal exam — 30 days at sea, 800 miles, 2 days as skipper and 12 night hours; with a Coastal Skipper practical completion certificate, 12 days and 400 miles.
Yachtmaster Offshore exam — 50 days at sea, 2500 miles, 5 days as skipper and five passages over 60 miles, two overnight and two in command, all within the last ten years.
ISSA
Inshore Skipper — entry asks only for one cruise already sailed and a radio operator's certificate; no separate mileage threshold appears in the requirements.
Offshore Skipper — 28 days at sea as skipper or watch leader, across at least two voyages and two sea areas. Schools additionally quote around 800 miles; check that with your school.
Night hours and night watches
Night hours are the tightest bottleneck. An ordinary week's charter produces almost none, since everyone is alongside by evening.
They come only on purpose: a night hop between islands, a departure in the dark to make a landfall at sunrise, a delivery with watches round the clock. Nearly every scheme counts hours under way — a night at anchor is not one.
What counts as night each body defines separately, usually the time between sunset and sunrise. Record the actual hours of your watch, not "spent the night on passage": that cannot be reconstructed later.
Where to find miles
Deliveries. In spring and autumn the fleet moves between bases and crew is wanted. Hundreds of miles in one go, night watches almost certain.
Racing. Inshore racing yields few miles but many hours of intense work; offshore racing yields both.
Friends with a boat. The most underrated source. Regular weekends add up across a season, especially if you get the helm and a watch.
Club outings and training. Set schedule, familiar water, clear roles.
Flotillas and training cruises. Miles that arrive with the school's confirmation attached.
Coasting along your own shore. Duller than the Mediterranean, but the miles are the same size.
The general rule: long passages beat short trips, and role beats distance. A week's delivery with two night watches beats a month of pottering about the bay.
Keeping the record straight
Write it up the same day. Not "I'll sort it at the end of the season": by then passages have merged, and dates and weather go first.
Keep one source of data, not three. A recorded track with date, time and distance answers half the questions by itself. What remains is the role, the crew and the weather — and the signature, taken aboard rather than chased by email a year later.
Once a month, total it up: miles, days at sea, days as skipper, night hours. Then at application time you have a ready table instead of three years to reconstruct from old photographs.
Frequently asked questions
How many miles do I need for Bareboat Skipper?
IYT asks for 200 nautical miles and 10 days at sea by the end of the course. The comparable ISSA rung, Inshore Skipper, sets no mileage threshold but wants one cruise already sailed. Requirements differ and change, so check with your own organisation.
How many miles do I need for a Yachtmaster?
It depends on the level and the scheme. For a coastal Yachtmaster, around 800 miles and 25 to 30 days at sea. For offshore, 2500 miles with the RYA and 3000 with IYT, plus 50 days at sea and separate demands for days as skipper and night hours.
Who signs off miles in a logbook?
The skipper of the passage in question, or the school if the miles were sailed on a course. The signature goes in aboard, straight after the passage. Note the name and contact details beside it: confirmation may be wanted years later.
How do I confirm miles for an ISSA certificate?
With a logbook carrying skippers' signatures and schools' stamps. ISSA counts days at sea as skipper or watch leader, so every entry must show your role, not only the distance. Ask your school about the paperwork.
Do miles count if I was a passenger?
As a rule, no. Miles are earned by taking part: standing watch, steering, working the sails. If you sunbathed for a week while someone else ran the boat, leave them out — such entries unravel at the exam.
What is the fastest way to build miles?
Deliveries and offshore racing: one long passage yields more than a dozen day sails and almost always adds night hours. Next fastest are regular outings with the same crew, where you get the helm and a watch.
What next
No need to count by hand. Press the round record button on every trip: the app logs the track by GPS and works out distance, time under way, speed and engine hours, screen locked or not. In the Logbook that becomes season totals — passages, miles, engine hours — and each boat card keeps its own history. Put your role and the skipper's name in the passage note: there are no fields for them, and they will not come back later.
Recording and reading a passage are set out in "Recording a passage" and "Reading a passage: map, charts, GPX"; the vessels in "My boats". The mechanics of the record are in "The yacht logbook: how to keep it and what to record", the choice of scheme in "Yacht licences: GIMS, IYT, ISSA and RYA — which one to get".
While the miles gather, do not let the theory go stale: the Learning section, the exams and the lights trainer keep it in shape, and Progress shows what has slipped. Short guides: "Tests and exams" and "Progress and weak topics".