About WorkHarbor

A career at sea runs on numbers that never quite fit a phone calculator. How many hours until landfall at the speed you are actually making good? How far is it, on a great circle, from the pilot station to the next port? How many TEU does that deck-and-hold mix really come to? What does the ship gross, and how much cargo can she lift on her marks? Who has the twelve-to-four, and how many hours a day does that leave each hand on watch? And, come licence-renewal time, how many qualifying sea days do those sign-on and sign-off dates add up to? None of it is hard on its own, but doing it by hand, voyage after voyage, is the part of the job nobody signed up for.

WorkHarbor exists to take that arithmetic off your plate. Rather than long articles you have to read end to end, the site is built around a set of small, single-purpose calculators aimed at the maritime and port-industry work seafarers, cadets, and shipping staff do every day. The Knots Speed Converter moves a speed between knots, miles per hour, kilometres per hour, and metres per second. The Nautical Distance & ETA Calculator turns distance and speed into a passage time, or works the great-circle distance in nautical miles between two latitude/longitude positions and reads out the ETA. The Cargo TEU Calculator turns a mix of twenty-, forty-, and forty-five-foot boxes into a twenty-foot-equivalent total and a physical container count. The Ship Tonnage Calculatorestimates gross tonnage from enclosed volume and displacement and deadweight from a hull’s dimensions and block coefficient. The Watch Schedule Planner turns crew size and a watch system into a clear rotation, and the Sea Time Calculator adds voyage dates into total sea-service days and months for certificate purposes.

Beyond the calculators, the blog and learn section cover seafaring life, shipping and logistics, and the reasoning behind the numbers the tools produce, and the Maritime Heritage Museum is a browsable collection of ships, ports, and maritime history, with every entry, image, and fact drawn from Wikipedia and Wikimedia Commons.

A few things worth stating plainly. WorkHarbor is an independent site, not affiliated with any shipping line, flag state, classification society, maritime administration, or training provider. It is supported by advertising, which is how the tools stay free with no account required. Every result the tools produce — a converted speed, a distance, an ETA, a TEU count, a tonnage estimate, a watch rotation, a sea-time total — is a general estimate built on the figures you enter and on standard conventions, not an official determination. For anything that actually matters to a passage or a certificate — passage planning, stability and load-line calculations, and qualifying sea-service in particular — verify with the ship’s officers, your company, class, or your maritime administration before you rely on it. If something looks off in a tool or an article, or you think a calculator is missing that would help, the contact page is the place to say so.