They worked from sun up to sun down. It wasn't until the industrial revolution that people started to work hours, shifts, and had weekends. If it took six months to make a pair of shoes that's what it took, if it took 2 years to build a boat that's what it took. Ninety percent of the world was farming so work was every day, all day until it was dark. There were no "vacations" and very few holidays. People had to eat and to survive meant that they worked as long as it was light out.
A person can spend up to 90,000 hours at work during their lifetime.
Fire
four
How many kilojoules are used during 8 hours of sleep?
Sailboats, like many inventions, were invented by many people in many places and so long ago that people weren't even writing then, never mind keeping records. (Prehistory.)
There are 24 hours IN a day. If you're asking how many hours there are DURING DAY TIME, it depends on where one lives. Countries like Singapore and Malaysia experience 12 hours during the day and 12 hours during the night. This depends on its location geographically.
325 BC[or]AD325
There are 24 hours during solstices, just like every other day of the year.
His (or perhaps her) name is lost to prehistory. Doubtless many people in many places tried to make connections between things they could observe in the heavens and events on Earth.
4383 hours.
Approx 12 hours, from 06.30ish to 18.30ish
3 or 4 hours