"I had to go check but all 3 of my scale boats are 24" and fall within the 10% rule in IMPBA. May be NAMBA is different, I don't know. "Wes,
What Master Hull Roster (MHR) are you using for dimensions? NAMBA and R/C Unlimited MHR give you a range which includes the +/-10%. I see 9401, 9601 Buds max widths to be 23.65" and 23.93" respectfully. IMPBA I year trial changes Engine and Boat Specifications to read: "All models must be of a real unlimited hydroplane listed in the APBA Master Hull Roster list." I have yet to find a MHR from the APBA, only R/C Unlimiteds Master Hull Roster or NAMBA 1/8 Scale Unlimited Hydroplane Master hull Roster appear to be available. CHEERS !!! Bob Johnson