There are no railways, waterways, ports or harbours on the island. Loading jetties are located at Kingston and Cascade, but ships cannot get close to either of them. When a supply ship arrives, it is emptied by whaleboats towed by launches, five tonnes at a time. Which jetty is used depends on the prevailing weather on the day. The jetty on the leeward side of the island is often used. If the wind changes significantly during unloading/loading, the ship will move around to the other side. Visitors often gather to watch the activity when a supply ship arrives.