Not legal 1 class
DD.7 bans lightened and gutted hulls, and no other hull work is listed for the class. DD.7, DD
- Drag, Turbo No Nitrous · DD.7
IHRA · Hull and handling
Modification of the OEM hull, IHRA
Work on the OEM hull itself: lightening, splitting, reinforcing, reshaping, cut-through repairs and centre wall removal. A replacement hull, the top deck, bulkheads, engine compartment foam, sponsons, the intake grate and the ride plate are answered on their own rows, not here.
This page is IHRA only, and the bodies do not agree. The same part under IJSBA and UIM. Which one applies to you is decided by whoever sanctions the race you enter.
Where it stands, class by class
29 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.
What each answer below means
- Not legal
- This comes off. The rules refuse it in this class.
- OEM part required
- This comes off. Only the part the manufacturer fitted is allowed here.
- Legal, with conditions
- Keep it, but measure it: the rules permit this part only inside stated limits.
- Legal
- Keep it. The rules permit this part in this class.
- No rule, this is an open class
- Probably keep it. The class carries no stock clause at all, so anything unlisted appears to be open. The rulebook does not say so in terms, and this is our reading rather than a permission anybody wrote down.
OEM part required 7 classes
The hull may be repaired but not otherwise modified, and a repair may not move it more than 2 mm (0.08 in) from its original configuration. · J.1, J.13
OEM part required 5 classes
A ski hull may be repaired, or reinforced against course obstacles, but only within 2 mm (0.08 in) of its original configuration, and no other hull work is listed. · J.1, J.13
OEM part required 1 class
Interior structural reinforcement is the only hull work allowed: no external change, nothing that alters the shape, running surface, strakes, chines or ride plate interface, and no added material that acts as ballast or shifts the weight distribution. · W.1, W.7.3
OEM part required 1 class
Splitting and lightening are both banned and no other hull work is listed, so only a repair within 2 mm (0.08 in) of the original configuration is open. DD.2, J.13, DD
- Drag, Sea-Doo Pro Stock · DD.2
OEM part required 1 class
S.6.1 lets an aftermarket hood be used for hull modifications, yet no Vintage Ski clause says which modifications, so the only quotable allowance is J.13: repair or reinforcement within 2 mm (0.08 in) of the original configuration. · J.1, J.13, S.6.1
Legal, with conditions 2 classes
A modified OEM hull is eligible if it meets the class limits of 97 in maximum length and a width between 20 and 30 in.
- Ski 1100 Modified · R.1
- Ski 1500 Modified · Q.1
Legal, with conditions 1 class
Work is confined to the area forward of the intake grate, and the hull may be neither split nor lightened. A cut through the hull may be repaired only from outside on an FZR or FZS, and inside and out on a GP, VXR or FX. Where fitted the centre wall may come out, and hull and top deck are joined by rivets, bolts, adhesive or an equivalent. · DD.1
Legal, with conditions 1 class
Work is allowed forward of the intake grate, with a cut through the hull repaired inside and out. The hull may be split but not lightened, the centre wall may come out where fitted, and plastics may be drilled for more air. The hull must be sealed together by rivets, bolts, adhesive or an equivalent. · DD.3
Legal, with conditions 1 class
The hull stays OEM, and lightening it is the one change listed, along with drilling plastics and the top deck for more air. · DD.4
Legal, with conditions 1 class
Work on the hull is open under T.6.4 while the top deck stays as the manufacturer supplied it, and no modification may take the craft past the original deck length. · T.6.4
Legal, with conditions 1 class
CC.1 opens any change section CC does not restrict, and CC.5.1 sets two limits on the hull: it may be no smaller than the top deck's minimum measurements, and it must be joined to the deck by the original method. · CC.1, CC.5.1
Legal, with conditions 1 class
The OEM hull may be modified while it stays inside the length and width of the upper deck's bond flange measured by plumb bob, bumpers excluded, and it may carry no fins, rudders or skegs. A separated bond flange must be rejoined by the original method, such as high-strength adhesive. · K.1, K.8.1, K.8.5
Legal, with conditions 1 class
Modified OEM hulls are eligible under V.1, within the class limits of 120 in maximum length and a width between 26 and 38 in. · V.1
Legal 1 class
Lightened hulls are listed outright, as are carbon-fibre hulls and swaps between manufacturers. · DD.5
No rule, this is an open class 3 classes
The class states only what it bans and calls itself run what you brung, against a section DD preamble that says anything unlisted is illegal.
- Drag, 2 Stroke Unlimited · DD.12
- Drag, Stand Up Unlimited · DD.10
- Drag, Unlimited · DD.6
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 IHRA 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 10 of 29 answered, 9 with conditions