Many but not all sailboats have numbers displayed on their sail, what do those numbers mean?

I am looking for a general answer, not one specific to the random example image below.

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    This is awfully broad. It varies by country, region, time period, boat type, purpose (e.g. races, mortgages) etc. It can be voluntary and required. I did some research on just the Dutch situation (assuming we have our nautical systems handled) and there are pages and pages to write about this. I'm afraid you will have to limit to one specific country and exclude historical data to be able to get a decent answer.
    – user15958
    Sep 26, 2018 at 12:47
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    @JanDoggen It should be possible to right a brief overview, that does not address all the points. Consider the intro paragraph on this wikipedia page Sep 26, 2018 at 13:25

1 Answer 1


One word: Racing

The numbers themselves usually don't mean anything. Usually, the number is essentially "how many sails of this model have been produced before this one".

So, the first boat will have sail number 1, the 1000th will have sail 1000.

Not all boats will come with numbered sails. However, racing sailboats will always have them.

The numbers are then used to identify boats in races.

After some time, the sail number and the boat become the boat's identity, so when replacing sails the buyers usually specify the number so it can match their old worn out sails.

Sail numbering has virtually nothing to do with watercraft registration, that is dependent on the hulls, and is usually identified with stickers affixed to the hull.

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    The sails normally come blank and you buy your own iron-on sail numbers
    – Separatrix
    Oct 3, 2018 at 13:06

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