I’m pretty sure that it used to explain in the regs that it was in case of fire. You have a small, confined space, and back before the average fishhouse got supersized, you had lots of small skid houses where one guy had to sit in front of the door. You also had lots of guys heating houses with little wood stoves or with oil burners.
So something catches on fire, a guy is blocking the door from swinging in, bad deal.
If anyone has the regs from the 1970s, I’m pretty sure it used to explain this.
Grouse