What is the 'Rapid Launch' feature? More so what does it involve.

I picked up a 4 lever/4 valve/2 motor control box that has a hole for this option in the top cover plate, but nothing was there. There is nothing in the bottom end. I'm assuming it is for an additonal valve that is for extra venting, in addition to the standard thru the motor venting, but there are no extra ports avaible.
And whats with that?? Water/air vented back thru an electric motor.

It's a big rubber ban wrapped around the transom. Push a release button and it sling shots you off the hoist.

it opens up the side of the "manifold" at the bottom (where the 4 vavles connect to)

Thanks.