On my last Grand trip there was a Jack's Culebra, that we traded off paddling.
It was an incredible R-2 joyboat, pretty close to unflippable even with novice paddlers. Pissed me off to watch the Culebra flying through the roaring gut of rapids that I was tempted to sneak (in a Pack Cat).
It was also an amazing search-and-rescue craft.
The Culebra crews retrieved lost oars, rescued half-drowned kayakers, and even busted back upstream into keeper eddies (e.g. the righthand cliff suck on Specter) to retrieve a trapped duckie (the paddler having taken a thrilling swim).
Pic below of Culebra rocking in the grip of the Grand:
Seriously great fun boat for Grand trips and other bigwater thumpers— given plenty of support craft.