No first hand experience, but get another bilge pump with long enough hose to get over the side , hook up to battery and drain

 

your outflow may be above the waterline. it is on my Alumacraft Trophy. thus will drain normally at the dock. the inflow is powered by a pump - outflow is gravity via another hose.

 

I think the drains are close to to but above normal water level.

 

My 2018 pro guide deep v tracker has a pump out live well. Inside the live well is pipe you push in or pull out for recirculate or pump out and use the manual switch....I think that's how it works. I usually just gravity drain at the ramp like you. I have only used the pump out a couple times.

 

the Alumacraft has a similar feature. have not used in years... but it does pump from livewell, through bait tank, and into the motor splashwell to then drain out the scuppers.

 

The drain is definitely below the normal water line, its on the bottom of the boat.

 

As long as the tank is above the water line it will still drain. My mako drain is below the water line and drains just fine at the dock

reelylivinsportfishing.com

 

and as long as that hose to the tank is sealed below waterline (no holes, breaks, leaks) , water will backup to the waterline level but the remainder of the water in the tank will drain out. if there are holes in that hose below the waterline - well, boat will sink eventually....