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Class Legality

UIM · Exhaust

Through-hull exhaust outlet flap removal, UIM

UIM answers this part for 16 of its classes, and publishes no rule for it in 8 more. 0 of those answers permit the part outright and 2 permit it with stated conditions, leaving 14 that do not. 5 of the ones that do not are classes we read as open rather than as refusing it. 10 are inferred from how the class is written rather than quoted from a rule naming this part. 8 are inherited from a parent class the rulebook points at.

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 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.
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.
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 legal 3 classes

The exhaust system must remain entirely of origin as delivered by the manufacturer, so the through-hull outlet flap may not be removed. · 501.02.03.03

Not legal 1 class

Two-stroke exhaust systems must remain entirely of origin, and four-strokes have no exhaust article and stay stock, so on either engine the through-hull outlet flap may not be removed. · 502.02.03.03, 502.02-02

Legal, with conditions 2 classes

Two-stroke: allowed. Four-stroke: not specified, therefore stock.

Through-hull exhaust outlet flap removal: 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 UIM class · where the rulebooks differ · checks on parts the shop sells · how this site reads a rulebook.

Exhaust · two and four stroke · legal in 2 of 16 answered, all with conditions

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