My dad got me started racing in spade-hulled "kneeboats", similar to class G when I was 8. My 1st boat was 6 1/2 feet long with an 18hp Merc racing engine.
My fastest "Tower of Power" was an XS1500 on a 14' Cacci Craft, which threw a rod one day at about 82-83 mph at, you guessed it, 6750 rpm. The connecting rod just missed me.
The fastest I got on the water personally was when I was managing a marina and Alan Green, the founder of Quicksilver Surf products, brought me a new 21' Allison with a 225 SuperSix Suzuki, complaining that it would only go 74 mph. The dealer told him he couldn't make it go any faster. I told him for $6K plus expenses I would get him 20% more speed, 90 mph. After blueprinting the hull and changing him over to a Merc 225 EFI, adding a jackplate, nosecone, etc., etc., we got the boat to radar a true 112 mph at 6700 rpm. Only cost him $19K including the motor.
The fastest boat I ever rigged was in Ocean City, MD, when I rigged a homemade 25' plywood and glass Chincoteague Scow with twin 300hp 3.4L big block Mercury motors for . Chincoteague Scow racing is a phenomenon at the Eastern Shore. This boat ran a reported 118 mph, although I never ran it over about 85 when testing it.
BTW, I quit going real fast on the water after I stuffed a 30' Velocity at 65-70 mph off of Ft. Lauderdale during a regatta in 1985. That one hurt. I had bruises in the shape of the throttles for a couple weeks.
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Common Sense is learning from your mistakes. Wisdom is learning from the other guy's mistakes.
Fr. Frank says:
Jesus liked fishing, too. He even walked on water to get to the boat!
Currently without a SeaCraft 
(2) Pompano 12' fishing kayaks
'73 Cobia 18' prototype "Casting Skiff", 70hp Mercury