Imagine a piston engine airplane (let's say a DC-3) flying at cruise speed and altitude over a calm sea, trying to reach an unreachable airstrip straight ahead, just above sea level. Fuel is very low and ditching may occur at some point even if highest lift to drag to consumption ratio is achieved.
Would a ground effect low horizontal flight increase the range? That could mean ditching closer to the shore, and getting help sooner (or even landing safely).
If yes, is it also the case for a modern jet airliner usually cruising faster and in a much thinner air, and are there some emergency procedures or regulations about that?