Racing

Classes in plain words

What Stock, Limited and GP mean, and where each rulebook says so. Mostly it does not: all three use the word Stock in their operative rules and none defines it in its glossary. What the words mean in practice comes from each book's closed-list principle, which is set out below in the book's own sentence, and from each class's own criteria, which live on its legality page.

The words: defined, or only used

Word	IJSBA glossary	UIM glossary	IHRA glossary
Stock	Used, not defined	Used, not defined	Used, not defined
Limited	Used, not defined	Used, not defined	Used, not defined
Superstock	Used, not defined	Not checked in that glossary	Not checked in that glossary
Modified	Used, not defined	Used, not defined	A racing category where specific, regulated modifications to the watercraft are allowed for competitive performance. (EE, Appendix A, Glossary of Terms)
GP, Grand Prix	Not checked in that glossary	Used, not defined	Used, not defined
Open	Used, not defined	Not checked in that glossary	Not checked in that glossary
Spec	Used, not defined	Not checked in that glossary	Not checked in that glossary
Ski	Not checked in that glossary	Used, not defined	A racing division for stand-up watercraft, typically requiring higher skill levels for operation. (EE, Appendix A, Glossary of Terms)
Runabout	Not checked in that glossary	Used, not defined	A racing division for sit-down watercraft with a larger size and engine capacity than stand-up models. (EE, Appendix A, Glossary of Terms)
Freestyle	Not checked in that glossary	Used, not defined	Not checked in that glossary
Homologated	Not checked in that glossary	Used, not defined	Used, not defined

IJSBA 2025, Glossary appendix, read from the rulebook on 2026-09-07. UIM 2026, glossary, read from the rulebook on 2026-09-08. IHRA 2026, EE, Appendix A, Glossary of Terms, read from the rulebook on 2026-09-11.

The two terms a parts catalogue leans on hardest, Stock and Replacement Part, are both undefined here. IJSBA defines Replacement Part against Aftermarket Part and that distinction decides legality in its closed-list classes. IHRA defines Aftermarket and stops. Do not carry IJSBA's definition across to fill the gap.

The UIM does define the craft itself: A mono-hull vessel using an inboard engine - thermal or electric, not excluding prototypes or new technologies - powering a water-jet pump as its primary source of propulsion. (500.01). IHRA defines it as A water vehicle designed to carry one to three individuals, powered by a single jet drive or enclosed prop propulsion system, classified as a Class A inboard boat by the United States Coast Guard. (J.2) and lists its racing divisions as Ski, Sport, Runabout 1100, Runabout (1200-1800cc); Divisions are further broken down by displacement, such as Lites, or by engine type, such as Four-Stroke only.

What Stock means in practice: each book's governing sentence

Closed list

The class names the changes allowed; everything else stays as the factory built it.

A part on the list

goes through
- Legal
- Legal, with conditions where the list sets a limit
A part the list never names

stops
- Not permitted, not listed in the rules

Set of limits

The class names what may not change, or how far it may go; everything else is open.

A part inside every stated limit

goes through
- Legal, with conditions where a rule names it
- No rule, this is an open class where none does
A part past a stated limit

stops
- Not legal

Why a class reads as open

Stated: in IHRA Freestyle the rulebook says outright that any change its list does not restrict is permitted (CC.1).
Our reading: UIM GP1 prints no stock clause, so we read it as open, though the rulebook never says so (501.04, 502.04).
Our reading: 3 IHRA drag classes (Unlimited, Stand Up Unlimited and 2 Stroke Unlimited) call themselves run what you brung, while the drag section's own preamble says anything unlisted is not legal, so their open reading is ours (DD.6, DD.10, DD.12).

A class is written one of two ways, and which way decides what happens to a part nobody mentions.

How we know: the governing sentences set out below: IJSBA SSK.1.1 and its sister clauses, UIM 501.01.01 and 501.04, 502.04, IHRA A.2.2, J.1 and CC.1. The endings are the badges each class page prints.

IJSBA

In Stock, Limited, Superstock, Spec and Vintage-Limited type classes the watercraft must remain strictly stock EXCEPT where the rules explicitly allow or require a substitution. If the rule book does not say you may, you may not. (SSK.1.1, SKL.1.1, FSSK.1.1, RAS.1.1, RAL.1.1, RSS.1.1, RNA.1.1, VSC.1.1, VSKL.1.1, VSK.1.1)

Silence in a class document means PROHIBITED, not permitted. A part that is simply unmentioned is illegal in these classes. Modified, Grand Prix, Open/GP and Freestyle documents still open with "only modifications explicitly permitted are allowed", but the permitted list is broad enough that most aftermarket categories are named. (SKGP.1.1, ROP.1.1, SPGP.1.1, FREST.1.1, SKM.1.1)

The chain. Limited inherits all Stock Class provisions unless otherwise noted. Superstock inherits all Limited Class provisions unless otherwise noted. Vintage Ski Limited inherits Stock Class provisions. A "not addressed" entry in Limited/Superstock/Vintage-Ski-Limited resolves by walking UP the chain to Stock, not by defaulting to permitted. (RAL.1.1, RSS.1.1, VSKL.1.1)

UIM

There is NO rulebook-wide governing principle. Neither 200 Interpretation of Rules, nor 407 Priority of These Rules, nor the preamble to the 500 Technical Rules states one. The principle is stated separately INSIDE each production class, and it is deliberately absent from the GP1 classes.

Aquabikes must remain strictly stock, except where the rules allow or require substitutions or modifications; substitutions or modifications not listed are not permitted. Applies to ski-gp4, ski-gp3, ski-gp2, runabout-gp4, runabout-gp3, runabout-gp2 (501.01.01, 501.02.01, 501.03, 502.01-02, 502.02-02, 502.03-02). Silence means PROHIBITED in these six classes. The exact decimal of the stock clause varied between extraction passes (for Ski GP2 it was reported once at 501.03.01 MAIN CRITERIA and once at 501.03.02 HULL). The clause is definitely present; treat the precise sub-number as unverified.

Ski GP1 (501.04) and Runabout GP1 (502.04) carry NO stock-conformity clause and NO closed list. Both are framed as classes promoting competition "with a higher degree of modification", with the rider bearing sole responsibility for component selection and the UIM technical commissioner empowered to report anything dangerous to the Race Committee. Silence means FREE in these two classes, bounded only by the dimensional, weight, sound, fuel, homologation/logbook and safety rules that ARE stated. The rulebook never says in terms that unlisted areas are free in GP1. It is the natural reading of the absent clause, and it is the only reading consistent with prototypes being expressly permitted, but it remains our reading rather than a rule anybody can quote. This is reported rather than confirmed: read once, in one document, and not checked against a second.

The chain. GP2 explicitly inherits GP3: "all modifications permitted in GP3 class are allowed in GP2" (501.03.02 Ski, 502.03-02 Runabout). GP3 does NOT inherit GP4 - the chain is one link long, not a ladder. (501.03.02, 502.03-02)

IHRA

One principle, stated twice in the front matter and operative everywhere except Freestyle. The absence of a specific rule, regulation, or prohibition does not imply permission. Modifications are strictly limited to those explicitly permitted, and any modification not listed is prohibited unless explicitly approved. (A.2.2, J.1) All watercraft must remain in their original stock configuration unless a specific substitution or modification is expressly allowed. (J.1)

Freestyle inverts the default. Its rules state the limits of allowed modification, and in the rulebook's words "any modification not explicitly restricted in this list is permitted". (CC.1) This is the one inversion in the document and it is stated outright, not inferred. It is a different kind of thing from UIM's GP1 classes, where the open reading comes from the absence of a closed-list clause rather than from a sentence.

Drag racing states the closed list harder than the front matter does. "The rules listed here are what you can and cannot do. If it is not listed here then it will not be legal." (DD)

Repairs, updates, backdates and like-for-like parts are permitted only where they produce no performance advantage and bolt on without modifying the part or anything else. (J.7, J.7.1, J.11, J.12) Changes, modifications or fabrications made for safety purposes are allowed, provided the watercraft remains safe to operate. Reinforcement of brackets or fittings against known failure risks is permitted where it does not enhance volume or performance. (J.1)

The chain. Ski Limited publishes no standalone technical rules. P.1 sends four-stroke craft to the Four Stroke Ski Lites section with no exceptions and E-85 allowed, and P.2 sends two-stroke craft to the Ski Lites section plus a listed set of additional modifications. An answer about Ski Limited is an answer about section N or section O, and a page that did not say so would be quoting the wrong rulebook section at a reader. (P.1, P.2)

IJSBA

Runabout

Runabout Stock
all Stock Class provisions carried in, unless noted (RAL.1.1)

Runabout Limited
all Limited Class provisions carried in, unless noted (RSS.1.1)

Runabout Superstock

Vintage

Stock Class provisions: the clause names no document
carried in, unless noted (VSKL.1.1)

Vintage Ski Limited

Sport

IJSBA Open class rules: the text names no single document
for the Kawasaki Gen 1 X2 (pre 2005) only: both its upgrade options follow these (Sport Spec opening, unnumbered)

Sport Spec

Ski and the rest

None of the 7 ski class documents says it takes another class's rules, so no arrow is drawn. Nor do the other 8 IJSBA classes, beyond Runabout Open / GP's note that its rules also serve a class titled GP or Grand Prix.

UIM

Ski

Ski Division GP3
everything GP3 permits is allowed (501.03.02)

Ski Division GP2

Runabout

Runabout GP3
everything GP3 permits is allowed (502.03-02)

Runabout GP2

Apart

GP3 takes nothing from GP4, and GP1 nothing from GP2. The other 16 UIM classes publish no component rules of their own.

IHRA

Ski

Four-Stroke Ski Lites
four-strokes in Ski Limited race under the rules above, no exceptions, E-85 fuel allowed (P.1)

Ski Limited
two-strokes in Ski Limited race under the rules below, plus a listed set (P.2)

Ski Lites

The rest

The other 26 IHRA classes state no such link.

An arrow means a class's own text takes in another class's rules, unless that class notes otherwise. The three books are built differently, and no one ladder from Stock to GP holds across them.

How we know: the clauses themselves, RAL.1.1, RSS.1.1, VSKL.1.1 and the Sport Spec opening (IJSBA), 501.03.02 and 502.03-02 (UIM), P.1 and P.2 (IHRA), with each class named as its own record names it.

The Technical Inspector and Race Director have final authority on whether a modification complies. Any published reading, including this one, is subordinate to that decision on the day. (J, J.1, J.3.3)

The IJSBA displacement guide disagrees with the class documents

Not a manufacturer/model table. It is a list of maximum displacements per class keyed by engine type. Only three models are named in the entire document. The 2021 Displacement Guide and the 2024/2025 class documents disagree in several places (Vintage Ski 650 vs the class doc's 600cc; Vintage X2/SC 800cc vs the class docs' 850cc; Ski GP forced induction 900cc vs the class doc's 1100cc). The class document is the more recent source. Flag rather than silently pick.

IJSBA 2025, 2021 Displacement Guide, read from the rulebook on 2026-09-07. Marked disputed.

Every class, with what its record states

73 classes: 57 with their own rules, the rest sporting classes that borrow a technical class's rules or disciplines with a format of their own. 60 records name eligible craft, 13 state a minimum weight and 44 a sound limit. The craft column is the first sentence of each record's entry; the whole entry, and the class's criteria, are on the legality page each name links to, which is where a word like Stock gets its meaning for that class.

International Jet Sports Boating Association

ski (7)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Ski Stock	Has its own rules	SSK	Exclusively the 1500cc-based Kawasaki SX-R.	not stated in this document	86 dB(A) at 22.86 m
Fixed Steering Ski Stock	Has its own rules	FSSK	The 1500cc-based Kawasaki, restricted to craft equipped by the manufacturer with a fixed steering system rather than a handlepole.	not stated in this document	86 dB(A) at 22.86 m
Ski Lites	Has its own rules	SKL	Exclusively Kawasaki SX-R and Yamaha SuperJet.	not stated in this document	86 dB(A) at 22.86 m
Four Stroke Ski Lites	Has its own rules	FSKL	OEM Ski PWC, four-stroke, max 1100cc.	not stated in this document	86 dB(A) at 22.86 m
Ski Superstock	Has its own rules	SKSS	As Ski Stock	not stated in this document	86 dB(A) at 22.86 m
Ski Modified	Has its own rules	SKM	OEM homologated naturally aspirated four-stroke engines only.	not stated in this document	86 dB(A) at 22.86 m
Ski Grand Prix	Has its own rules	SKGP	Start from a stock OEM watercraft.	not stated in this document	86 dB(A) at 22.86 m

vintage (4)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Vintage Ski	Has its own rules	VSK	Designed for the original Kawasaki 550 Ski.	not stated in this document	86 dB(A) at 22.86 m
Vintage Ski Limited	Has its own rules	VSKL	Original Kawasaki 550 engine cases must be used.	not stated in this document	86 dB(A) at 22.86 m
Vintage X2	Has its own rules	VX2	Kawasaki X2, sold from 1986 through 1995.	not stated in this document	86 dB(A) at 22.86 m
Vintage SC	Has its own rules	VSC	Kawasaki SC.	not stated in this document	86 dB(A) at 22.86 m

runabout (6)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Runabout Rec Lites	Has its own rules	RRL	As of Jan 1, 2021 - Sea-Doo Spark (all years and models) and Yamaha EX (all years and models, EXCLUDING the EXR).	must weigh within no more than 10 lb (4.54 kg) lighter than OEM weight as determined by IJSBA	86 dB(A) at 22.86 m
Runabout Stock	Has its own rules	RAS	Watercraft must remain strictly stock except where the rules allow or require substitutions.	four-stroke runabouts must weigh within no more than 35 lb (15.88 kg) lighter than OEM weight as determined by IJSBA	86 dB(A) at 22.86 m
Runabout Naturally Aspirated	Has its own rules	RNA	Four-stroke Stock Class watercraft combined with two-stroke Limited Class watercraft.	not stated in this document (note this DIFFERS from Runabout Stock's 35 lb tolerance)	86 dB(A) at 22.86 m
Runabout Limited	Has its own rules	RAL	Craft must remain strictly stock except as specified.	not stated in this document	86 dB(A) at 22.86 m
Runabout Superstock	Has its own rules	RSS	Four-stroke engines only.	not stated in this document	86 dB(A) at 22.86 m
Runabout Open / GP	Has its own rules	ROP	Starting point is a stock OEM watercraft.	four-stroke runabouts equipped with a supercharger or turbocharger must weigh a minimum of 550 lb (ROP.2.1). No minimum stated for naturally aspirated craft.	100 dB(A) at 22.86 m

freestyle (1)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Freestyle	Has its own rules	FREST	One homologated PWC per competitor.	not stated in this document	86 dB(A) at 22.86 m

sport (2)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Sport Spec	Has its own rules	section headings, no numbered rules	model: Kawasaki X2	not stated in this document	86 dB(A) at 22.86 m
Sport GP	Has its own rules	SPGP	Must begin with a stock OEM watercraft as the base unit.	a four-stroke Sport PWC with a supercharger or turbocharger must weigh within 40% of the weight of the original donor PWC (SPGP.2.1). No absolute figure. No requirement for NA or two-stroke craft.	100 dB(A) at 22.86 m

Union Internationale Motonautique

ski (10)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Ski Division GP4	Has its own rules	501.01	50 specimens manufactured, marketed and available, with a conformity certificate (500.02.01)	160 kg dry	86 dB(A) at 24 m
Ski Division GP3	Has its own rules	501.02	50 specimens, marketed, conformity certificate (500.02.01)	135 kg dry	86 dB(A) at 24 m
Ski Division GP2	Has its own rules	501.03	As Ski Division GP3	135 kg dry for a two-stroke, 165 kg dry for a four-stroke	86 dB(A) at 24 m
Ski Division GP1	Has its own rules	501.04	PROTOTYPES EXPRESSLY PERMITTED.	135 kg dry	90 dB(A) at 24 m
Ski Ladies GP1	Sporting class, rules from ski-gp1	314	not on the record	not on the record	none stated
Ski Veterans GP1	Sporting class, rules from ski-gp1	302.01.05	not on the record	not on the record	none stated
Ski Juniors GP3.2	Sporting class, rules from ski-gp3	302.01	not on the record	not on the record	none stated
Ski Juniors GP3.3	Sporting class, rules from ski-gp3	302.01	not on the record	not on the record	none stated
Ski Juniors GP4	Sporting class, rules from ski-gp4	302.01	not on the record	not on the record	none stated
Ski Future Electric (SFE)	Sporting class	302.01	not on the record	not on the record	none stated

runabout (9)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Runabout GP4	Has its own rules	502.01	As Ski Division GP3	180 kg dry	86 dB(A) at 24 m
Runabout GP3	Has its own rules	502.02	As Ski Division GP3	216 kg dry	86 dB(A) at 24 m
Runabout GP2	Has its own rules	502.03	As Ski Division GP3	310 kg dry	86 dB(A) at 24 m
Runabout GP1	Has its own rules	502.04	PROTOTYPES EXPRESSLY PERMITTED via a UIM-issued logbook, valid 4 years, presented at every technical inspection.	300 kg dry	90 dB(A) at 24 m
Runabout Juniors GP4	Sporting class, rules from runabout-gp4	302.01	not on the record	not on the record	none stated
Runabout Ladies GP4	Sporting class, rules from runabout-gp4	302.01.01	not on the record	not on the record	none stated
Runabout Veterans GP1	Sporting class, rules from runabout-gp1	302.01.05	not on the record	not on the record	none stated
Jet Raid	Discipline, rules from multiple - see eligibleClasses	317.01	not on the record	not on the record	none stated
Offshore	Discipline, rules from multiple - see eligibleClasses	317.02	not on the record	not on the record	none stated

freestyle (2)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Freestyle Free	Discipline	312	302.01 lists Freestyle Free and prints no displacement for it.	not on the record	none stated
Freestyle Amateur	Discipline	312	max 800 cc	not on the record	none stated

multi (2)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Parallel Slalom	Discipline, rules from multiple - see eligibleClasses	313	not on the record	not on the record	none stated
Endurance	Discipline, rules from multiple - see eligibleClasses	317.03	not on the record	not on the record	none stated

hydrofly (1)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
UIM Hydro-Fly	Discipline	900	Runabout, minimum 260 HP, maximum 360 HP	not on the record	none stated

International Hot Rod Association, Pro Watercraft Racing

ski (9)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Ski GP	Has its own rules	K	Aftermarket hulls with OEM four-stroke engines, and modified OEM hulls with four-stroke engines.	not stated	none stated
Ski GP2	Has its own rules	L	Exclusively the Kawasaki SX-R 1500.	not stated	86 dB(A) at 22.86 m
Ski GP3	Has its own rules	M	Kawasaki 750SX, 750SXI and 750SXI Pro, Kawasaki SXR800, and the Yamaha SuperJet in both its two-stroke and four-stroke forms.	not stated	86 dB(A) at 22.86 m
Four-Stroke Ski Lites	Has its own rules	N	Exclusively the Yamaha SuperJet four-stroke, 2021 or later.	not stated	86 dB(A) at 22.86 m
Ski Lites	Has its own rules	O	The Kawasaki SX-R 800 two-stroke and the Yamaha SuperJet two-stroke.	not stated	86 dB(A) at 22.86 m
Ski Limited	Has its own rules, rules from multiple: four-stroke-ski-lites for four-stroke entries, ski-lites for two-stroke entries, plus the P.2 additions this class publishes itself	P	Four-stroke craft eligible for Four Stroke Ski Lites, and two-stroke craft eligible for Ski Lites.	not stated	86 dB(A) at 22.86 m
Ski 1500 Modified	Has its own rules	Q	Aftermarket hulls with OEM 1500 four-stroke engines, and stock or modified OEM hulls with OEM four-stroke engines.	not stated	86 dB(A) at 22.86 m
Ski 1100 Modified	Has its own rules	R	Aftermarket hulls with OEM four-stroke 1050 engines, and stock or modified OEM hulls with OEM four-stroke engines.	not stated	86 dB(A) at 22.86 m
Ski Vintage	Has its own rules	S	The Kawasaki 550 is the primary eligible craft.	not stated	86 dB(A) at 22.86 m

sport (3)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
X2 Vintage	Has its own rules	T	The Kawasaki X2, built 1986 to 1995.	not stated	86 dB(A) at 22.86 m
Sport Spec	Has its own rules	U	Kawasaki X2 pre-2005, Kawasaki X2 2005 to 2007, Sea-Doo HX, Yamaha WaveBlaster 701 and Polaris Hurricane.	not stated	86 dB(A) at 22.86 m
Sport GP	Has its own rules	V	Approved aftermarket hulls and modified OEM hulls, two-stroke and four-stroke.	stated and unusable. See the uncertainty below.	86 dB(A) at 22.86 m

runabout (6)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Runabout Endurance	Has its own rules	W	Seated personal watercraft designed for two or more riders and fitted with a fixed seat, remaining OEM stock in configuration and performance.	not stated. W.7.3 separately forbids adding material to increase weight or alter weight distribution.	none stated
Runabout GP	Has its own rules	X	All four-stroke watercraft, provided displacement stays within the division limit.	not stated	86 dB(A) at 22.86 m
Runabout GP2	Has its own rules	Y	Most two-stroke and four-stroke watercraft, subject to class availability.	not stated	86 dB(A) at 22.86 m
Runabout GP3	Has its own rules	Z	Most two-stroke watercraft under 800cc and four-stroke watercraft under 1100cc, subject to class availability.	not stated	86 dB(A) at 22.86 m
Runabout Lites	Has its own rules	AA	Sea-Doo Spark in all years and models, Yamaha EX in all years and models, and the 2025 and later Yamaha JetBlaster DLX and DLX 3-Up.	not stated	86 dB(A) at 22.86 m
Runabout Limited	Has its own rules	BB	The class criteria state hull dimensions, displacement ceilings by engine type and a sound limit, and name no models.	not stated	86 dB(A) at 22.86 m

freestyle (1)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Freestyle	Has its own rules	CC	Not restricted by model.	not stated	none stated

drag (10)

Class	Kind	Section	Eligible craft, the record's first sentence	Minimum weight	Sound limit
Drag, Yamaha Pro Stock	Has its own rules	DD.1	Must start as an OEM Yamaha personal watercraft.	not stated	none stated
Drag, Sea-Doo Pro Stock	Has its own rules	DD.2	Must start as an OEM Sea-Doo personal watercraft.	not stated	none stated
Drag, Yamaha Spec	Has its own rules	DD.3	OEM Yamaha personal watercraft.	not stated	none stated
Drag, Sea-Doo Spec	Has its own rules	DD.4	OEM Sea-Doo personal watercraft.	not stated	none stated
Drag, Super Stock	Has its own rules	DD.5	OEM personal watercraft from any manufacturer.	not stated	none stated
Drag, Unlimited	Has its own rules	DD.6	Must be a personal watercraft.	not stated	none stated
Drag, Turbo No Nitrous	Has its own rules	DD.7	Not stated.	not stated	none stated
Drag, Stand Up Unlimited	Has its own rules	DD.10	A stand-up personal watercraft from any manufacturer, named in the rulebook as including but not limited to Kawasaki, Yamaha and Fast Powersports.	not stated	none stated
Drag, Sea-Doo vs Sea-Doo	Has its own rules	DD.11	Must start as an OEM Sea-Doo personal watercraft, Sea-Doo only.	not stated	none stated
Drag, 2 Stroke Unlimited	Has its own rules	DD.12	A two-stroke runabout personal watercraft from any manufacturer, named in the rulebook as including but not limited to Kawasaki, Yamaha, Sea-Doo and Polaris.	not stated	none stated

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: 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.

73 classes · 57 with their own rules · 0 of 3 bodies define Stock