RedactedNarrative: Vessel 1 Operator states he was pulling a flotation device with nylon rope.  Operator stated his son and friend were on the device when the rope became slightly tangled. Operator states he went to untangle the rope and while doing so the engine of the pontoon was not in neutral but not going fast either. Operator stated the pulling of the boat allowed the rope entanglement to slice the tip of his right-hand ring finger off. The amputation was below the nail bed but above the first crease. Operator was transported by Fontana EMS to Janesville Mercy Hospital. Operator stated that the finger was not able to be reattached.