Let us know what boat you're on... sounds like relatively high freeboard, which is always a challenge, esp on an older boat without a stern platform of some sort.
So model and year would let us get a mental picture of what you're describing...
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)