Guess the mark: a Solent racing-marks quiz
I built a browser game for learning the Solent racing marks: a nautical chart, a highlighted buoy, and a multiple-choice question against the clock.
When a race officer in the Solent calls a course, they call it by mark name: round Royal Thames, leave Gurnard to port, finish at Prince Consort. The Solent Cruising and Racing Association’s list runs to about 160 marks, and a crew that has to find each one on the chart gives away time to a crew that already knows where they are. There is no shortcut to knowing them: it is rote learning, the same as flags or lights. Rote learning is what quizzes are for, so I built one: Guess the Mark, a free browser game for learning the Solent racing marks.
How it works
The game shows you a nautical chart (OpenSeaMap tiles on a Leaflet map) with one racing mark highlighted and a handful of named options to choose from. Pick the right name before the timer runs out and you score; pick wrong and you see which mark it actually was.
The questions are built so you cannot bluff your way through. Marks within a couple of kilometres are drawn on the chart as context, because in real racing you identify a mark partly by its neighbours. Hill Head means little on its own; Hill Head with the shore and the next buoy along is a position you can learn. The wrong answers always include at least one mark of the same colour and type as the target, so you cannot eliminate options by symbol alone. You have to know where the thing is.
Three difficulty levels split the list. Beginner sticks to the marks with famous names: the forts, towers and ledges that anyone who has sailed the central Solent will recognise. Intermediate brings in the sponsored racing buoys, which change name with their sponsors and are the ones crews actually argue about. Advanced uses all 160-odd marks in the SCRA list. There is also a proximity mode that limits questions to marks within a chosen radius of Cowes, for anyone whose racing rarely leaves the central Solent.
Scoring rewards speed and consistency. A correct answer is worth a base score plus a time bonus that scales with difficulty; answering three or more in a row earns a streak bonus. The grade at the end gives you something to beat.
How it is built
The marks come from the SCRA’s published GPX file for the season, parsed in the browser — name, position, buoy type and sponsor for each mark. The app is React and TypeScript, built with Vite and served from Cloudflare Workers, so it loads quickly and works on a phone in a sailing-club bar, where most arguments about mark names happen.
The data updates with the racing season, since sponsored marks change names as sponsors come and go. If you race in the Solent, or you are working through an RYA course and want the local knowledge to stick, give it a go and tell me where it is wrong.