If you fired up your boat without hooking it to any water source, especially after having it sit for any extended period of time, you probably didn't break just 1 vane from your impeller, but you probably broke every one of them off instead. NEVER, EVER, EVER, EVER, under any circumstance start your boat without it being in the water or hooked up to a hose.
The impeller vanes are rubber, rubbing against a metal housing. They burn up and break off very quickly when they start spinning while they're dry, and they start spinning as soon as the starter starts trying to turn the motor over. If you started it for the first time after sitting all winter, the rubber impeller had also probably began to seat to the metal housing, making it even harder to spin and break loose on the first start while dry. Impellers need to be lubricated, and water is their lubricant. It's like having a prostate examination with no lube... you wouldn't like that would ya?
The good news is, you could fix this yourself for the cost of an impeller at www.skidim.com
instead of paying for what will probably end up being a 500+ dollar dealer visit. If you decide to do it yourself, be sure to go through all the hoses after the impeller housing up all the way to your thermostat, because that's more than likely where all of the vanes you broke off are piled up at.