Modern pirates favor small boats and taking advantage of the small number of crew members on modern cargo vessels. They also use large vessels to supply the smaller attack/boarding vessels. Modern pirates can be successful because a large amount of international commerce occurs via shipping. Major shipping routes take cargo ships through narrow bodies of water such as the Gulf of Aden and the Strait of Malacca making them vulnerable to be overtaken and boarded by small motorboats. Other active areas include the South China Sea and the Niger Delta. As usage increases, many of these ships have to lower cruising speeds to allow for navigation and traffic control, making them prime targets for piracy.