The ground wire on one of my trim Cylinders snapped in half. Do I need to replace this before I use the boat again?

No - It's a bonding wire to help fight off electrolysis. I would repair it - but if you don't leave the boat in the water for long periods of time - you'll be fine.

Thanks, The boat sits on a lift. I wanted to go out tomorrow and then put it on the trailer to do some maintance. Good time to fix it!

Like was said, its to connect the drive to the mercathode system and prevent eloctolysis. Not a big deal and no reason not to take the boat out.