Vintage classes and the 2025 rule vote

In plain words. Racers asked for six changes to the old Kawasaki 550 class. The IJSBA's managing director advised against two of them, extra sponsons and changes to the hull bottom. The board refused the hull change but allowed the sponsons, titanium drive parts and a clearer pump-length rule. Other race series write their own vintage rules.

In January 2025 the IJSBA's board voted on five suggestions for the Vintage Ski class, the rules for racing the original Kawasaki 550 stand-up. This chapter sets the 2024 rule book beside the suggestions, the managing director's advice and the result, dated to the IJSBA's own 2024 posts and to the trade press that reported the 2025 round.

Words on this page (7)

run whatcha brung: An open class or event where riders race whatever personal watercraft they bring. IHRA's drag rules call the Unlimited Class basically a run what you brung class, open to any PWC but barring surface props, and print Run What Ya Brung for the Stand Up Unlimited and 2 Stroke Unlimited classes.
Sponson: A device fixed to the side of the hull to steady the craft and improve its handling, as IHRA's glossary describes it. IJSBA's hull guide sorts them into tubbies, which bulge from the hull side, and standard sponsons, a projection that is often a wing or a block. The rulebooks let racers fit, move or remove them within limits on how many, how long and how far they stand out from the hull.
Super Chicken: Two-word form. The VintageJetSki.com shop menu labelled the Kawasaki SC as SC (Super Chicken). A 2015 PWCToday post also expands SC as Super Chicken.
Vintage SC: IJSBA vintage class for the Kawasaki SC, exclusively on the 1991 OEM SC hull, capped at 850cc
Vintage Ski: IJSBA class for the original Kawasaki 550 Ski. Max 600cc at World Finals
Vintage Ski Limited: IJSBA vintage class capped at 558cc on original Kawasaki 550 engine cases, with 110mm rods and 60mm stroke only
World Finals: The IJSBA’s annual championship, run at Lake Havasu City.

The 2024 rules, and a round that asked for little

Confirmed

The IJSBA posted its recommendations for the 2024 rule book on 4 January 2024, for its board to vote on the next day. On Vintage Ski it reported many comments asking for what it called excessive improvements, and said there was not enough public support to recommend them. It recommended a short list instead, described as consistent with repairing and maintaining vintage hulls or fitting modern products inside them: modified hull liners and bulkheads, aftermarket flotation foam, a fuel filler from another homologated craft, an aftermarket flywheel cover and relocated electrical parts. On 12 February 2024 the IJSBA posted the 2024 Vintage Ski rules for six days of peer review, and the 2024 class document prints each of those items. That document opens by calling the class a limited and nostalgic performance level with access to aftermarket parts, built for the original Kawasaki 550 on original 550 engine cases. Four of its rules matter for what followed. VSK.2.4 allows a maximum of two sponsons. VSK.6.1 forbids a titanium driveshaft, impeller housing or stator vane assembly, and lets the whole pump and nozzle assembly be no more than 50.00mm longer than original equipment. VSK.4.3 allows aftermarket fuel injection, while VSK.5.2 says no additional sensors may be added to the engine's electronics. Three sentences are in the document and not in the February draft: two allow an upper deck other than the original with the IJSBA's written approval, where that deck has been approved in the IJSBA's 550 racing before, and one requires the original lower deck.

Sources: IJSBA 2024 rule recommendations post; IJSBA Vintage Ski peer review 2024; IJSBA Vintage Ski document 2024

Six suggestions and the managing director's advice, December 2024 and January 2025

Likely

The Watercraft Journal printed the suggestions for the 2025 rule book on 31 December 2024, as racers sent them to the IJSBA. Six concern Vintage Ski. One would let anyone make and sell modified top decks under VSK 2.2. One would allow changes to the bottom of the hull within its original length and width. One would rewrite VSK 2.4 as one set of tubbies at the front and one set of sponsons at the rear, a set being a left and a right, because inspectors read the word sponson differently. One would end the clash between fuel injection under VSK 4.3 and the ban on added sensors under VSK 5.2. One would allow titanium under VSK 6.1, its author arguing that titanium driveshafts cost little beside other engine and pump work. And one would clarify that VSK 6.1 measures the whole pump and nozzle assembly, because a 750 pump has no shoe in the assembly and a 550 pump does. The managing director's recommendations, reported on 10 January 2025, take up five of them; the top deck suggestion is not among them. The recommendation on the hull bottom was no, to control costs and keep to the class's intent. The recommendation on sponsons was also no, calling the change a further departure from the goal of Vintage Ski, given as showing the traditional power, handling and style of the early craft. Both answers warned that the class could split if more exotic changes were allowed. On fuel injection the answer was possibly, pending work with technical inspectors. Titanium was recommended because public input supported it, with a comment from the managing director against it on cost, and the pump measurement was recommended to make 750 pumps easier to use.

Sources: Watercraft Journal 31 December 2024; Watercraft Journal 10 January 2025

The vote, 15 January 2025

Likely

The IJSBA's board voted at its meeting of 15 January 2025, and the adopted changes were posted the next day and due in the online rule book on 22 January, the date The Watercraft Journal reported the results as the association's executive director gave them. Of the four Vintage Ski items on which the managing director had said yes or no, the board agreed on three and differed on one. The hull bottom change did not pass. The sponson change, allowing one set of traditional sponsons and one set of tubbies, passed, with an additional sponson rule to be published; this is the one where the board did what the managing director had advised against. Titanium under VSK 6.1 passed. The clarification that VSK 6.1 measures the overall length of the complete pump and nozzle assembly, to allow for the 750 pump, passed. On fuel injection and the sensor rule the report records no vote: the IJSBA said it could not identify language conflicts preventing aftermarket fuel injection in Vintage Ski. Every vintage item in the round, as reported, names the Vintage Ski class and its rules, and none names Vintage Ski Limited, Vintage X2 or Vintage SC.

Sources: Watercraft Journal 22 January 2025; Watercraft Journal 10 January 2025

What the 2024 document printed against what the 2025 one is read to print

Likely

Set side by side, the 2024 document and the 2025 Vintage Ski document as this site's class notes read it show three of the reported results in the text. Sponsons go from a maximum of two in VSK.2.4 of 2024 to up to four in 2025, two traditional bladed and two tubbie-type. Titanium goes from forbidden for the driveshaft, impeller housing and stator vane assembly in VSK.6.1 of 2024 to permitted in 2025. The pump and nozzle assembly goes from no more than 50.00mm longer than original equipment in 2024 to a figure the class notes give as 139.7mm measured from the transom, a different way of measuring that the notes mark as an open question. The 2025 file is linked from the IJSBA rule book page with the date 2025; its words were not read for this chapter. The site's article setting Vintage Ski against Vintage Ski Limited reads that 2025 document part by part, and the 2024 text is what it replaced.

Sources: IJSBA Vintage Ski document 2024; IJSBA rule book page; Watercraft Journal 22 January 2025

The 2025 World Finals plans vintage additions

Likely

The Watercraft Journal's summary of 26 August 2025 traces the vintage additions to that year's World Finals, held from 4 to 12 October 2025. The class list posted in early August carries Ski Vintage and X2 Vintage. On 15 August the IJSBA announced the tentative addition of a Vintage Ski 550 class, to become final only if enough paid entries arrived by 1 September. The same report says Vintage Ski 550 and Vintage Super Chicken classes would be added to the schedule, the first early in the week and the Super Chicken, the Kawasaki SC, towards Thursday and Friday, and it quotes the tentative schedule as including Vintage Ski 550 Limited and Vintage SC. The report names the added ski class both as Vintage Ski 550 and as Vintage Ski 550 Limited, so which of the two it was is not clear from it.

Sources: Watercraft Journal 26 August 2025

Vintage classes outside the IJSBA book

Likely

Other promoters write vintage rules of their own. Full Throttle WaterX announced its vintage classes for 2022, as The Watercraft Journal reported on 1 February 2022. Its Vintage Ski Open takes Kawasaki 440, 550, 650 and 750 skis, Yamaha's square-nose SuperJets, and Cobra and PJS hulls, with twin engines to 785cc. Vintage 550 Mod takes 440 and 550 hulls to 600cc on original Kawasaki cases. Vintage 550 Limited, which the series called a more affordable run whatcha brung class, allows only the original rear sponsons and no 750 pump swap. Vintage X2 Open and X2 Limited are for first-generation X2 hulls, and the Superchicken class is run whatcha brung to 1100cc. Its Open, Mod and X2 classes allow two sets of sponsons; the report does not say what a set is, so whether that matches the IJSBA's 2025 change is not known here. Round-nose SuperJets of 1996 to 2007 and Polaris Octanes go to a two-stroke Ski Limited class. Pro Watercross's class list for its 2025 Triple Crown, reported on 8 April 2025, has one vintage class, Vintage Ski, Run What You Brung, and prints no rules for it.

Sources: Watercraft Journal 1 February 2022; Watercraft Journal 8 April 2025

The 2026 round

Likely

The next round did not take up the vintage classes, as far as the trade press reported it. The Watercraft Journal's account of the managing director's recommendations for the 2026 rule book, published on 31 December 2025, names three subjects, fuel in Stock and economy classes, the pump in Sport Spec and compression in Ski Lites, says there were no Stock class changes, and mentions no vintage item. Comments were open until 13 January 2026, before the board's decision.

Sources: Watercraft Journal 31 December 2025

Not covered, and why (5)

Vintage Ski was the largest class at a World Finals.: A class-size claim built on entries, which this archive does not print as a trend or a comparison, whatever the year; the chapter gives no entry or field figure for any vintage class.
The vintage community is pushing its class towards modern performance parts against an authenticity line.: Our research notes' reading of one vote. The documents show suggestions, advice and a result for one season, and the 2024 recommendations post reports requests for more performance that found too little public support the year before; a direction of travel for a whole community is not in them.
The 2025 vote settled what titanium may be used in Vintage Ski Limited.: Every vintage item in the 2025 round, as reported, names the Vintage Ski class and its rules. None names Vintage Ski Limited, X2 or SC.
The name of the managing director who wrote the 2025 recommendations, and of the person who wrote the comment on titanium.: The trade report prints the post and not a name, and a person is named only where Key Figures has a record and a source ties the name to the words.
The 2025 World Finals ran a vintage Limited class, and how many entered it.: The report of 26 August 2025 calls the addition tentative and gives a deadline for it to be confirmed; no result sheet or later report was read, and entry figures are not printed here.

What could not be read (6)

The IJSBA's own posting of the 2025 results, dated 16 January 2025 in the trade report, and its 2025 Vintage Ski document were not read: ijsba.com showed a captcha on 10 October 2026, and the Wayback index for 2024 onward lists no capture of either. The rules below are as the trade press reported them on 22 January 2025.
The trade report of 10 January 2025 says an ad hoc rule review committee made recommendations of its own, submitted to the board with the managing director's. The committee's recommendations were not found, so whether the board followed them on sponsons is not known here.
The results report says an additional sponson rule would be published. Its wording was not read; what the 2025 class document prints on sponsons is known here only through this site's class notes.
No report of the January 2026 board vote was found on 10 October 2026, so whether any vintage rule changed for 2026 is open.
The trade report of 26 August 2025 names the added class both Vintage Ski 550 and Vintage Ski 550 Limited. Which IJSBA class document it ran under, and whether it ran at all, was not found.
Full Throttle WaterX's own post of its 2022 vintage classes was not read, and no later list from that series was found, so whether those classes still ran in 2024 to 2026 is open. Pro Watercross's 2025 list prints no rules for its vintage class.

The sanctioning body's own 2025 documents were not read here: ijsba.com answered with a captcha on 10 October 2026, which was not passed, and the 2025 Vintage Ski file has no archived copy. The 2024 rules are read from the IJSBA's own posts and class document as archived in 2024. Every 2025 suggestion, recommendation and result is as The Watercraft Journal reported it, on the date given, and a trade report of a vote is not the rule book's wording. A rule in a book shows what was allowed, not who raced under it.

Documents cited in this chapter

IJSBA 2024 rule recommendations post (web.archive.org): IJSBA Releases Recommendations For 2024 Rule Book Changes (IJSBA news post of 4 January 2024, Wayback capture of 5 January 2024), International Jet Sports Boating Association, 2024-01-04; sanctioning body, high. The association's own recommendations for the 2024 rule book, for its board to vote on 5 January 2024. Its discussion reports many comments asking for what it calls excessive improvements in Vintage Ski, without enough public support, and recommends five Vintage Ski items on hull liners, bulkheads, flotation foam, the fuel filler, the flywheel cover and electrical parts. High as the body's own post; the byline is not used.
IJSBA Vintage Ski peer review 2024 (web.archive.org): IJSBA Releases Vintage Ski Rules For Peer Review (IJSBA news post of 12 February 2024, Wayback capture of 13 February 2024), International Jet Sports Boating Association, 2024-02-12; sanctioning body, high. The 2024 Vintage Ski rules posted in full as a draft, to become permanent in six days. It lacks three sentences the published 2024 document carries, two on approved replacement upper decks and one requiring the original lower deck; otherwise the rules cited from the document read the same. High as the body's own post.
IJSBA Vintage Ski document 2024 (web.archive.org): Vintage Ski (550), IJSBA class document, file 2024-Vintage-Ski.pdf (Wayback capture of 6 April 2024), International Jet Sports Boating Association, 2024-02; sanctioning body, high. The eight-page 2024 Vintage Ski class document, uploaded in February 2024. Cited for VSK.1, VSK.2.2, VSK.2.4 (a maximum of two sponsons), VSK.4.3 and VSK.5.2 (fuel injection allowed, no added sensors) and VSK.6.1 (no titanium driveshaft, impeller housing or stator vane assembly; pump and nozzle assembly no more than 50.00mm over original). High as the body's own rule text; the published date is the upload folder.
Watercraft Journal 31 December 2024 (watercraftjournal.com): IJSBA Releases Set Of Rule Suggestions For 2025 Rule Book (The Watercraft Journal, 31 December 2024), The Watercraft Journal, 2024-12-31; enthusiast media, medium. Trade-press reprint of the racers' suggestions for the 2025 rule book with the association's notes, six of them on Vintage Ski rules VSK 2.2, 2.4, 4.3, 5.2 and 6.1. Medium because the IJSBA's own posting was not read.
Watercraft Journal 10 January 2025 (watercraftjournal.com): IJSBA Releases Managing Directors Recommendations For 2025 Rule Book Changes (The Watercraft Journal, 10 January 2025), The Watercraft Journal, 2025-01-10; enthusiast media, medium. Reprints the managing director's recommendation on each suggestion and reports an ad hoc rule review committee's separate recommendations, not printed. On Vintage Ski: no to the hull bottom and to the sponson change, possibly on fuel injection, yes to titanium and to the pump measurement. It names no person as managing director. Medium as trade press.
Watercraft Journal 22 January 2025 (watercraftjournal.com): IJSBA Announces Annual Meeting And Rule Change Results (The Watercraft Journal, 22 January 2025), The Watercraft Journal, 2025-01-22; enthusiast media, medium. The results of the board's vote of 15 January 2025 as the association's executive director reported them, posted 16 January and due in the online rule book on 22 January. On Vintage Ski: hull bottom did not pass; one set of sponsons and one of tubbies passed; titanium passed; the pump length clarification passed; no fuel injection conflict found. Medium as trade press relaying a post not read.
IJSBA rule book page (ijsba.com): IJSBA Competition Rule Book (the current per-class documents), International Jet Sports Boating Association; sanctioning body, high. The live page, read on the accessed date. It links no single book but per-class PDFs dated 2021 to 2025, twenty of them class documents, plus general, competition and appendix documents. The class and body records on this site were read from these PDFs on 2026-09-07; the chapter's figures for the current set come from those records and from the page itself, not from a re-reading of the PDFs.
Watercraft Journal 26 August 2025 (watercraftjournal.com): IJSBA World Finals Registration, Schedule & Latest Rule Changes, Plus Recap of Releases (The Watercraft Journal, 26 August 2025), The Watercraft Journal, 2025-08-26; enthusiast media, medium. A summary of the IJSBA's posts for the 2025 World Finals: the tentative addition of a Vintage Ski 550 class on 15 August, the Vintage Super Chicken addition, a schedule quoted as including Vintage Ski 550 Limited and Vintage SC, and an early-August class list with Ski Vintage and X2 Vintage. Its entry threshold and prices are not used. Medium as trade press.
Watercraft Journal 1 February 2022 (watercraftjournal.com): Full Throttle WaterX Announces Updated Vintage Classes for 2022 (The Watercraft Journal, 1 February 2022), The Watercraft Journal, 2022-02-01; enthusiast media, medium. Reprints the series' social media announcement of six vintage classes, with eligibility and sponson, pump and engine allowances for each. Reached from the short address watercraftjournal.com/?p=47554. Medium because the series' own post was not read.
Watercraft Journal 8 April 2025 (watercraftjournal.com): Pro Watercross Celebrates 30 Years Of Racing With 2025 Triple Crown Series (The Watercraft Journal, 8 April 2025), The Watercraft Journal, 2025-04-08; enthusiast media, medium. The 2025 Triple Crown schedule and class list, which includes Vintage Ski, Run What You Brung, with no rules printed for it. The series' own statements about its standing in the sport are not used. Medium as trade press.
Watercraft Journal 31 December 2025 (watercraftjournal.com): IJSBA Releases Managing Director's Recommendations for 2026 Rule Book Changes (The Watercraft Journal, 31 December 2025), The Watercraft Journal, 2025-12-31; enthusiast media, medium. Summarises the managing director's recommendations for 2026: fuel in Stock and economy classes, the pump in Sport Spec and compression in Ski Lites, with comments open to 13 January 2026. It reports no vintage item. Medium as trade press summarising a post not read.

Cite this page

“Vintage classes and the 2025 rule vote”, BaddJet archive, https://baddjetarchive.com/racing/history/vintage-classes-the-2025-vote/

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