UIM · Hull and handling

Ballast weight kits, UIM

Only the GP1 classes have a ballast article - and they are the ones with the lowest weight minima.

This page is UIM only, and the bodies do not agree. The same part under IHRA and IJSBA. Which one applies to you is decided by whoever sanctions the race you enter.

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This is one body's answer, not the sport's. You are bound by whichever body sanctions the event you enter. If you race more than one series, build to the stricter answer. The differences are set out in the rulebook comparison.

This matters commercially: GP2 Runabout carries the heaviest minimum in the book at 310 kg and has NO ballast permission, while GP1 carries 300 kg and may ballast up to it.

Where it stands, class by class

24 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. 8 of them borrow another class’s rules and are marked below; for those, the link to the parent class is read from the categories table rather than stated in the rulebook. 8 publish no rule for this part and name no parent to borrow one from, and are grouped together at the end.

What each answer below means

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.

No rule published for this class

Unanswerable here. This class publishes no rule for the part and names no parent class to borrow one from, which is an absence in the rulebook and not a permission.

Not permitted, not listed in the rules 9 classes

Not listed in this class. Illegal under the class's own stock clause.

• Runabout GP4 · 502.01
• Runabout GP3 · 502.02
• Ski Division GP3 · 501.02
• Runabout GP2 · 502.03
• Ski Division GP2 · 501.03
• Runabout Juniors GP4 · 302.01 · borrows another class
• Runabout Ladies GP4 · 302.01.01 · borrows another class
• Ski Juniors GP3.2 · 302.01 · borrows another class
• Ski Juniors GP3.3 · 302.01 · borrows another class

Not permitted, not listed in the rules 2 classes

No ballast article.

• Ski Division GP4 · 501.01
• Ski Juniors GP4 · 302.01 · borrows another class

Legal, with conditions 3 classes

Constant mass only, within the normally exposed areas of the hull, no fluids, requiring no modification or relocation of other parts. Weight control is performed with an empty fuel tank and all other liquids at race level. 501.04.05/.06

• Ski Division GP1 · 501.04
• Ski Ladies GP1 · 314 · borrows another class
• Ski Veterans GP1 · 302.01.05 · borrows another class

Legal, with conditions 2 classes

Ballast of constant mass may be added within the normally exposed areas of the hull before competition to reach the 300 kg minimum, with no fluid ballast and no modification or relocation of other parts. · 502.04-05, 502.04.02-07

• Runabout GP1
• Runabout Veterans GP1 · borrows another class

No rule published for this class 8 classes

No component rules are published for this class and no single parent class is named, so this part cannot be answered for it. That is an absence in the rulebook, not a permission.

• Endurance · 317.03
• Freestyle Amateur · 312
• Freestyle Free · 312
• Jet Raid · 317.01
• Offshore · 317.02
• Parallel Slalom · 313
• Ski Future Electric (SFE) · 302.01
• UIM Hydro-Fly · 900

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Ballast weight kits: 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.

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