I've been searching for Sunken Crypts for about 40-50 in game days.
I'm only really able to play this game for a few hours at a time, once every few nights, I'm a cautious gamer, who takes it slow, enjoys it all, I never enter a new area unprepared.
I have mapped out two decent sized swamps already and found no Sunken Crypts at all in either, I've never died in the Swamp, so fearing a bug, I briefly considering checking my seed if there were any at all.
I resisted and two IRL days ago I set sail and found a new island with a patch of Meadows, surrounded by Black Forest, with Swamp trees visible in the east.
I took it as a sign, set up an outpost and set off for the new Swamp.
Within minutes… TWO CRYPTS.
It has taken me so flooping long to find one. The joy at running straight into one, getting in and out with full pockets with no panic, no problems with enemies, and finally get my scrap iron is so, SO, satisfying.
I felt I should share.