A G&S game boat from the US. They are designed for the record chasers to go super fast with in reverse. They have an upward sloping transom under the waterline to help them plane in reverse and shafts in tunnels to keep the shaft angles low for efficiency and so they don't drag the arse down. I've seen one in the flesh, "Desperado" at Cairns and there is one in NZ setting records galore, "The Hookin' Bull".