Tramp shipping involves irregular shipping over non-standard routes without a definite schedule. Tramp ships carry bulk and break-bulk cargoes of low value that do not require fast delivery. Charterparties are contracts drawn up between ship owners and charterers to lease vessels. The main charter types are voyage, time, and demise charters. Voyage charters are most common in tramp shipping. Liner shipping operates on a fixed schedule and route. It can carry large volumes but is slower than air transport. While reliable for cargo quality, liner shipping faces delays and reliability issues regarding arrival times.