Racing

Race numbers

How big, where, what colour, and who assigns them. The UIM answers all four with figures and a typeface; IHRA answers three and adds the tie rule for two riders on one number; IJSBA splits them, placement in an appendix drawing and the figures in its scoring document at SCOR.8.

---

Side by side

IJSBA 2025, Appendix, Racing Number Location, read from the rulebook on 2026-09-07. UIM 2026, 206, read from the rulebook on 2026-09-08. IHRA 2026, D.7, read from the rulebook on 2026-09-11.

International Jet Sports Boating Association

The Racing Number Location appendix is a picture with no body text, showing placement zones only: a panel on the upper hull side toward the bow plus a smaller lower panel (runabout/sport), a panel on the hood side (stand-up ski), and a panel on the hull side forward of the seat (runabout). The figures the appendix leaves out are in the Scoring, Authority, Discipline, Protests and Appeals document at section SCOR.8, held here since 2026-09-30. Numbers and backgrounds are coloured by rider classification, black on orange for Novice, black on yellow for Expert and black on white for Pro (SCOR.8.1). Backgrounds are at least 20cm high and 15, 23 or 30cm wide for one, two or three digits (SCOR.8.2). Numbers are at least 18cm high, spaced at least 13mm apart, in standard block type with no shading or outlining (SCOR.8.3). The 2018 edition of the same document printed every one of these figures at 7.8.1 to 7.8.3, so none of them changed with the renumbering.

Absent from the appendix, by a targeted read: stroke width.

Union Internationale Motonautique

Numbers are designated at the beginning of the season, unchanged for the entire championship, and number one is reserved for the reigning World Champion in each class. The panel is at least 30 x 30 cm, the digits at least 22 cm high with 13 mm between them, in black digits, Arial Black typeface, on a white background, for ALL categories. Livery: non-conforming numbers integrated into the aquabike livery can be accepted if clearly readable by timing officers and race officials. Bibs: numbered racing bibs required at World and Continental Championships; only promoter-approved bibs allowed. Fuel: transported fuel tanks must display the racing number at 7 cm height (702).

Not stated in rule 206: placement on the craft is not stated; number of places numbers must appear is not stated; stroke or line width is not stated; national letters or country codes are not stated; duplicate-number resolution is not stated.

International Hot Rod Association, Pro Watercraft Racing

Read from the held text of version V.20260603 on 2026-09-26. Each rule is quoted where its wording is the rule and restated for the rest.

D.7.1 Visibility and placement

Race numbers must be clearly visible on both sides of the watercraft, with contrasting colors to the background for legibility. Both sides of the craft, contrasting with the background, and not in the footwell or on a horizontal surface. A rider who fails the visibility standard gets one warning; continued failure is disqualification.

D.7.2 Size and formatting

Race numbers must be at least seven (7) inches in height and displayed in a clear, legible manner. Only standard block-style numbers are permitted. Digits at least seven inches high in a standard block style. Legibility is the rider's responsibility; an illegible number may have to be corrected, and the rider may not be scored until it is.

D.7.3 Number selection and registration

Riders may select a race number from their local race organization or use a number they have earned. Two riders on one number in one class means the first to register keeps it. A rider in several classes whose number is taken may add an X. A rider who has not earned a number gives way to one who has. Changes are reported to registration.

All three can now be built to: the UIM states the figures and the typeface in one article, IJSBA states the placement in an appendix drawing and the figures at SCOR.8 of its scoring document, and IHRA gives a height and a style. Which body sanctions the event you enter decides which column applies.

---

Documents cited on this page

Source: IJSBA Competition Rule Book, the set of per-class and general documents, published by International Jet Sports Boating Association

Published by

IJSBA Competition Rule Book, the set of per-class and general documents, published by International Jet Sports Boating Association ijsba.com

Read on

2026-10-02

Worth knowing

Twenty-five separate PDFs on one page, published in different years (2021 to 2025). The set is cited as the 2025 rule book; a class document carries its own year, which is printed on that class's page. This row is the set; the two rows below are the general documents held as text.

Source: IJSBA Scoring, Discipline, Protests and Appeals (SCOR), 2025 document, published by International Jet Sports Boating Association

Published by

IJSBA Scoring, Discipline, Protests and Appeals (SCOR), 2025 document, published by International Jet Sports Boating Association ijsba.com

Read on

2026-10-02

Worth knowing

The current scoring document, 13 pages, titled Scoring, Discipline, Protests, Appeals and numbered SCOR.1 to SCOR.23, linked from the rule book page under "Scoring" (file created 2025-02-11; prints no year of its own). Fetched and held on 2026-10-02 by the edition watch, which found it beside the 2018 text the archive had extracted two days earlier; the 2018 rows point at these. Same twenty section headings in the same order as 2018, with the old numbering defects carried over (SCOR.2.2 inside SCOR.1, SCOR.3.1 twice).

Source: 2026 UIM Aquabike Rulebook, published by Union Internationale Motonautique

Published by

2026 UIM Aquabike Rulebook, published by Union Internationale Motonautique uim.sport

Read on

2026-10-01

Worth knowing

One 189-page document covering every class, so cross-class comparisons are same-season. Read straight from the PDF; the text is not held here and page numbers were not recorded, so a reference from this document cannot yet be followed to a page. Held here as extracted text from 2026-10-01, the same text the rule rows were read from on 2026-09-26.

Source: IHRA Pro Watercraft Racing Competition Rulebook, version V.20260603, published by International Hot Rod Association (Cuttell Motorsports, LLC)

Published by

IHRA Pro Watercraft Racing Competition Rulebook, version V.20260603, published by International Hot Rod Association (Cuttell Motorsports, LLC) ihra.com

Read on

2026-09-07

Worth knowing

Sections A to EE, 95 pages. The URL is the rules page rather than the PDF, because the PDF is served from a signed link that expires. The version string is the figure to cite; the rulebook changed four times between February and June 2026.