But we're not concerned about how fast the ice melts, as much as we are concerned about how long the cooler stays cold.My experience is exactly the opposite. The water, based on physics, will melt more ice than if you drain the water.
The water you drain is coooold. It doesn't matter what state it's in, solid or liquid. It's the same as removing cold ice.
That drained cold water is then replaced by air.
Hundreds of times of experience. --I could have paid for refrigeration by now
Tried the drain version, box got warm much faster.
Of course, only ice in the cooler might keep the food colder, but for a much shorter amount of time, and we are talking longevity here.