Hello Jillbrown... For my Skipper, I either leave her in the pilothouse seat or on the table in front of the wheel. She cannot jump off either -- too high. Also, I have up netting over the pilothouse doors. She has jumped up the step, across the side deck and fallen overboard. Believe me, she is not her most attractive when wet.
Net:
Skipper does chase fish and has launched herself at them. When in the dink I either leash her or keep her close to me so she won't try to catch something underwater.
The net came from Defender's and is the stuff sailboats use to keep their gear on deck. It's not expensive.