IJSBA · Hull and handling
Work on the OEM hull itself: repairs, reinforcement, splitting at the bond flange, lightening and reshaping. A replacement hull or top deck, sponsons, the intake grate, the pump cover plate and trim tabs have their own rows, and engine compartment foam and bulkheads are not answered here.
This page is IJSBA only, and the bodies do not agree. The same part under IHRA and UIM. Which one applies to you is decided by whoever sanctions the race you enter.
20 classes, grouped where the same rule gives the same answer rather than listed one by one, because an answer that holds for a class usually holds for every class that borrows its rules.
OEM part required 9 classes
The hull may be repaired but not otherwise modified, and a repair may not alter the original configuration by more than 2.00mm (0.08 in.).
OEM part required 1 class
Repairs may move the hull no more than 2.00mm (0.08 in.) from its original configuration, the inside of the hull may not be reinforced, and its outer surface texture may differ from OEM only while every shape stays exactly as OEM. · RRL.2.2
OEM part required 1 class
No hull work is listed: the hull and top deck stay exactly as the manufacturer furnished them. · VSKL.2.2
OEM part required 1 class
The 1991 SC hull stays as the manufacturer furnished it, and only the deck may be reinforced internally. · VSC.2.2
OEM part required 1 class
The hull stays as the manufacturer furnished it, and the one change listed is cutting or modifying the hull liner while the full hull thickness moves by no more than 2.0mm (.079 in). · VSK.2.2
Not permitted, not listed in the rules 1 class
Not listed in this class document. Illegal under the closed-list principle.
Legal, with conditions 2 classes
Separating the bond flange is the only work on the OEM hull the class lists: it must be rejoined by the original method, such as high-strength adhesive, and nothing else on the OEM hull may change.
Legal, with conditions 1 class
Repairs may move the hull no more than 2.00mm (0.08 in.) from its standard configuration, the hull may be reinforced internally, and a Kawasaki Gen 1 X2 (pre 2005) may add front hull fills reaching no more than 36 in back from the bow.
Legal, with conditions 1 class
Hull work is open under VX2.2.2 while the top deck stays original, provided the hull ends up no longer than the top deck. · VX2.2.2
Legal, with conditions 1 class
The hull may be modified within the plumb-bob outline of the original upper deck's bond flange, bumpers removed, and may be no smaller than the top deck's minimum measurements. A separated bond flange is rejoined by the original method, and hazardous fins, rudders and skegs are barred. · FREST.2.2, FREST.2.3
Legal, with conditions 1 class
The hull may be modified within the length and width of the upper deck's bond flange by plumb bob, bumpers removed, with no hazardous fins, rudders or skegs, and a separated bond flange is rejoined by the original method. The 1500cc Kawasaki SX-R is the exception: it must keep exact OEM hull dimensions. · SKGP.1, SKGP.2.2, SKGP.2.3
Modification of the OEM hull: 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 · checks on parts the shop sells · how this site reads a rulebook.
Hull and handling · two and four stroke · legal in 6 of 20 answered, all with conditions