IJSBA · Hull and handling
The highest-stakes eligibility question in the book.
20 classes, grouped by the answer rather than listed one by one, because an answer that holds for a class usually holds for every class that borrows its rules.
Not legal 8 classes
Explicitly prohibited by this class document.
Not legal 1 class
Aftermarket hulls prohibited.
Not legal 1 class
Hull and top deck must remain as originally furnished.
Not legal 1 class
No allowance for aftermarket hulls.
Not legal 1 class
SKSS.1.1
Not legal 1 class
Exclusively the 1991 OEM SC hull.
Not legal 1 class
Exclusively the 1986-1995 OEM X2 hull.
Not legal 1 class
Upper deck substitution only by IJSBA WRITTEN approval, and the replacement deck must have historical approval in 550 competition.
Legal, within limits 1 class
IJSBA-approved aftermarket hulls and top decks permitted, must display IJSBA-recognised hull identification. · SKM.1.1
Legal, within limits 1 class
Legal if it does not exceed OEM upper-deck length/width. Max 165.1mm (6.5 in) shorter than OEM length, within 50.8mm (2.0 in) of OEM width. Ski deck absolute minimums 193cm x 68.5cm x 53.3cm.
Legal, within limits 1 class
Permitted via the Aftermarket Hull Homologation Process; the top deck must resemble the generic look of existing homologated Ski watercraft. EXCEPTION: the 1500cc Kawasaki SX-R must use the OEM hull and top deck.
Legal, within limits 1 class
Permitted only on watercraft homologated in numbers of 500 or higher, and the hulls themselves must be IJSBA-approved and homologated. · SPGP.3.2
Legal, within limits 1 class
Permitted if homologated at 500 or higher units and IJSBA-approved. Upper decks must be an exact OEM replica judged by a silhouette test. From Jan 1 2025 the engine block must be from the same manufacturer as the originating top deck.
Aftermarket hull or top deck: if the rule your class applies reads differently to you, or the rulebook has changed since this was read, ask. We answer with the section we read it from, or that we have not read it. Ask a rules question.
Every IJSBA class · where the rulebooks differ · signed checks on parts the shop sells.
Hull and handling · two and four stroke · legal outright in 5 of 20