What is the origin of the idiom "at loggerheads" and when to use it?

The idiom "at loggerheads" has its origins in the nautical term "loggerheads," which refers to round iron instruments with long handles, historically used to heat pitch for sealing seams in wooden ships. When sailors disagreed or argued, they often resorted to wielding these loggerheads as weapons. Over time, the term evolved to describe a situation where two or more individuals or groups are in a state of deadlock, unable to reach an agreement or resolve their differences.