According to the world of Doug:

Oh boy... will you really do that? Put it on the list for right after
they run a simulation of a wave approaching a hull from astern to show
how the transom keeps a wave out...

So, now we know you have never ever sailed offshore in a big sea. Open
transoms are not generally acceptable for really just one reason Doug,
even with no difference in 'buoyancy'. Can you really not imagine a sea
overtaking a running boat? The stern really doesn't rise immediately you
know! In some cases it even goes over the transom and can hit the helm
and even companion washboards. What on earth do you think stops it?
You've got Adlard Coles Heavy Weather right? Have a look at the boat
being overtaken by a wave. What a typical know it all dinghy sailor you
are.

Cheers