One trend that I suspect is that labor cost has risen and material cost have fallen since the time that thor built the wheel. this would seem to indicate that old stile coffins would be labor rich, material poor, while newer ones would be the opposite. This is somewhat offset by modern engineering and finite element analysis which allows one to create a seemingly equally as strong product w/ less material. But this came late in the age old quest of labor vs. raw materials.
Also the sleeping bag issue, I have one of those bags that are narrow at the feet, wider at mid to shoulder area, and smaller at the head. I use it when absolute weight savings are essential, but I hate it. The close shape and forcing the legs close together do conserver heat, but in reality it sux.
This is just a wag - never heard it anywhere else. The body is a bag full of levers and connective tissues controlled by electro-chemical reactions, not all of which cease when the proprietor vacates the premises, especially before embalming became common practice. I’ve heard of cadavers sitting up in morgues, and there is the common story of headless chickens running around barnyards. Also think of the old practice of placing coins on the eyelids of the departed to prevent the lids from opening in a disconcerting death stare. A tightly fit coffin would help to keep the body in a dignified pose - on back with face up, arms folded across chest and legs straight during the wake.
Explanations about saving materials do not make sense. The hexagonal coffin uses the about same amount of wood, just more of it winds up as useless scraps rather than part of the coffin. A hexagonal coffin does take more time and skill. This is another possible explanation. People would be more likely to leave it to the pros if they thought that the hexagon was too difficult, and they didn’t want neighbors and relatives to think they were a cheapskate by interring the departed in a simple box they knocked together.
From at least the 1350s until the end of the 16th c. the normal type of coffin was a narrow shallow box no more than about 18" wide and tapering towards the foot. It was slightly shallower than the corpse’s head, necessitating a gabled lid (or pitched roof, if you prefer). From around 1575 the ‘pinched in at the shoulders’ shape began to appear. Flat lids appeared in the 1590s and became popular in the 1670s.
A coffin was a status symbol - only rich people could afford to be buried in one. Poor people were buried in shrouds. Most parishes owned a reusable parish coffin in which the corpse was taken to the grave and then lifted out, and some of these parish coffins still survive. Coffins were made by the local carpenter or joiner - undertaker as a profession didn’t appear until the second half of the 17th c.
(See J Huggett, The Shaking of the Sheets; Death 1350-1660 ISBN 1 8504 109 0)
My wife used to work for C. J. Boots, a local maker of fine wooden coffins. The shape was rectangular, but the lids were rounded, glued up as a barrel-vault arc. They made a few that were wider, for wider occupants, and some smaller ones for children and infants. They made fancy boxes for cremated remains. Some funeral houses requested rental caskets with a hatch at one end and replaceable liners, because some families wanted a nice box for viewing before the body was cremated.
The plant manager, when he was introduced to someone, instead of shaking hands, would pull out a tape measure to size up the “customer.” Always got a nervous laugh.
An ‘undertaker’ now called a funeral director I guess, was originally a person who ‘undertook’ to organise all the different trades involved in a burial.
They were often carpenters, so made the coffin themselves, but many coffins were lined with lead which required the services of a plumber. They also arranged transport to the burial ground, the verger to dig the grave, the clergyman to carry out the service, and additional extras like flowers, bell ringers and a choir. Anyone who has had responsibility for a funeral, even these days, would usually prefer to pay someone to make all the arrangements.
Interesting that this should be resurrected so close to the day of the dead.
I think the reasoning about coffin shape is somewhat speculative. Also, in parts of the world that aren’t US, the hexagonal coffin is still pretty standard. It seems mostly US which uses caskets, the rectangular shape.
In parts of Ghana, there are all sorts of coffin shapes available. Check Fantasy coffins