A dockhand is employed by the city or port authorities, constant work for constant pay. The dock sues taxes and fees to cover this cost, having dockhands on site speeds up ships' turnaround quicker. Secondary is the extra security this provides the dock, a big step to stopping smugglers.
Dock work is laborious but steady, many hands make light work and quickly a group of dock workers become like brothers. Dockhands are renown for protecting each other, this can often lead to scuffles between sailors and the dock workers.