Not legal 1 class
No trim tab or extension clause appears in the class, and VSKL.2.2 keeps the hull as the manufacturer furnished it, so nothing may be added beyond the pump cover plate extension on its own row. · VSKL.2.2
IJSBA · Hull and handling
Hull extension, IJSBA
Rear extensions, bow appendages and planing surface extensions added to the hull. Most classes count an extension mounted on the transom as a trim tab, so those cells give the trim tab answer, and the pump cover plate extension stays on its own row.
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.
Where it stands, class by class
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.
What each answer below means
- Not legal
- This comes off. The rules refuse it in this class.
- Not permitted, not listed in the rules
- Treat it as coming off. The class requires the craft to stay stock except where the rules allow otherwise, and this part is not on the list, so this is our reading rather than a rule we can quote at you.
- Legal, with conditions
- Keep it, but measure it: the rules permit this part only inside stated limits.
Not legal 1 class
Hull extensions and trim tabs may NOT be used in Ski Lites, though mounting brackets may remain. · SKL.2.7
Not permitted, not listed in the rules 7 classes
Not listed in this class document. Illegal under the closed-list principle.
- Fixed Steering Ski Stock · FSSK
- Runabout Rec Lites · RRL
- Ski Stock · SSK
- Four Stroke Ski Lites · FSKL
- Runabout Naturally Aspirated · RNA
- Runabout Stock · RAS
- Ski Superstock · SKSS
Legal, with conditions 6 classes
An extension mounted on the transom counts as a trim tab, so it must be fixed in position, no wider than the planing surface and no more than 100.00mm (3.94 in.) past the end of the original planing surface, as on the fixed trim tab row.
- Sport Spec · section headings, no numbered rules
- Runabout Limited · RAL.2.6
- Vintage SC · VSC.2.7
- Vintage X2 · VX2.2.7
- Runabout Superstock · RSS.2.6
- Vintage Ski · VSK.2.7
Legal, with conditions 4 classes
The class counts any extension mounted on the transom as a trim tab, which may be fixed, automatic or rider controlled but no wider than the planing surface and no more than 100mm (3.94 in.) past its end, as on the trim tab rows.
- Freestyle · FREST.2.7
- Ski Grand Prix · SKGP.2.7
- Sport GP · SPGP.3.6
- Runabout Open / GP · ROP.3.6
Legal, with conditions 1 class
A bow appendage that diverts spray and stabilises handling may be fixed to the top deck only as an approved design listed on IJSBA's website. At the stern, SKM.2.7 counts an extension mounted on the transom as a fixed trim tab, no wider than the planing surface and no more than 100.00mm (3.94 in.) past its end. · SKM.2.2, SKM.2.7
Hull extension: 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 11 of 20 answered, all with conditions