When I was designing systems for handling hazardous and nuclear waste, we were always doing “fault trees” and asking, “If this component fails, what else will fail?”, and “The failure of what other components will affect this component?”
When one does such fault trees on a 18th century square rigged ship, the integrity of almost every system comes back to keeping the sailors warm. If the sailors go hypothermic, the ship’s systems fail. The weight of their garments affects how much work each sailor can do. If the sailors clothes weight more, then the sailor can do less work. If the sailor’s clothes are more bulky, then more space must be allocated to clothing and less to cargo. If the sailor clothes are not as warm, then the sailor needs to eat more, then the ship needs more space for food and cooking and there is less space for cargo. This goes on and on, and the issue of keeping the sailor warm is critical, and seemingly insurmountable. It is a matter of doing forensic engineering. The engineering says the ship will not work.
Engineers these days do not know about wool fabrics knit from worsted spun yarns and knit with long needles and a knitting sheath. Looking to the literature, the engineer sees the Victorian tradition of hand knitting, that says such fabrics are impossible to hand knit, and even if it could be done, the knitting would be too slow and costly to be useful. Thus, in the post Victorian era, such ships are impossible.
However, looking back at pre-Victorian knitting traditions, such fabrics were knit, and the technology to knit such fabrics rapidly and inexpensively was widely available. With such very warm, light fabrics, and the square rigged ships become feasible, but are such fabrics possible? The proof is in the knitting.
Someone who has never worn such garments thinks they are as impossible as an old sailor would think a modern cell phone was impossible. The possibly of a cell phone is proven by the existence of a cell phone. The possibility of warm, light weight fabrics is proven by knitting them.