RedactedNarrative: Vessel 1 (LA 3319 PU) was loading onto the trailer and partially on the trailer. Vessel 1 is an airboat. Vessel 2 (LA 3400 FP) was approaching the dock behind Vessel 1. Vessel 2 was a Gator Trax boat with a Go Devil long tail tiller steer. The operator of Vessel 2 thought that Vessel 1 was finished loading which is why he pulled in behind him. Not finished, operator of Vesssel1 got on the gas to finish power loading the airboat. As the thrust of air behind the propeller began to push Vessel 2, the operator jumped out of the vessel onto another vessel that was already tied to the dock. At this time, the Go Devil engine which was still running fell into the water, propelling Vessel 2 toward the back of Vessel 1. Vessel 2 began to spin in the water in a clockwish motion. The handle of the Go Devil, which was sticking into the air, entered the cage of the airboat striking the blades of the propeller which was running.  The operator of Vessel 1 immediately shut off the airboat engine when he heard the propeller strike. There was no alcohol involved. Vessel 2's engine was equipped with a kill switch and lanyard from the factory, but the kill switch and lanyard has since been removed from the engine.