No, it's too cramped to get a pan in there. Plus, the drain plug of which I speak faces UP. It's not under the engine like on a car.
You can buy an easy to use kit that has a
pump (either manual, like a bike
pump, or electric), hose and bucket to collect the old oil.
Moyermarine is really the best place to go to find out more info about maintaining your Atomic4.
Here are some good links:
Moyer Marine Atomic 4 Engine Rebuilding and Parts
First Oil Change - Moyer Marine Atomic 4 Community
Oil change issues - Moyer Marine Atomic 4 Community
Moyer Marine Inc. - include