I have a 22, and I only get water after it "really" rains hard (I have a few above water leaks, I plan on taking care of this season.). I have my pump, a small one, located in the space under the floor board. The space is really kinda small. It's located on the port side. The strbrd side will tend to fill up a-bit, till it spills to the post side. There is a rib that goes down the middle. With mine, it's usually a pretty small amount of water, and I have the pump hooked up to a float switch. I also have it hardwired to my fuse box, with a fuse. That may not be the best way, But it's been like that for the last 3 years. If I feel like I need to pump it out, I pick up the floor board and manually lift the float for a bit.
Although I've never used it. The manual lever pump is also one hell of a pump. On mine, it's situated a bit differently. The intake is a flexible hose, housed under the port "sitting area". The coil is about 6'ft long and about 1" , It would be easy to take that hose to suck out water from any other cavities.