THL: Stay a safe distance from vertical surfaces if there are significant waves present in the area. A passing boat or ship may generate big waves that escape your attention until there is no time to escape. An example is the North anchorage of the Golden Gate Bridge (but there are special cases, e.g. rough water classes or the OWRC regatta, when there is a fast flood coming through the Golden Gate, and it is useful to be close to the wall since the current is slower there).
The standard length races for the Olympics and the World Rowing Championships is 2 kilometres (1.24 mi) long; 1.5 kilometres (0.93 mi) - 2 kilometres (1.24 mi) for US high school races on the east coast; and 1,000 m for masters rowers (rowers older than 27). However the race distance can and does vary from dashes or sprints, which may be 500 metres (1,640 ft) long, to races of marathon or ultra-marathon length races such as the Tour du Léman in Geneva, Switzerland which is 160 kilometres (99 mi), and the 2 day, 185-kilometre (115 mi) Corvallis to Portland Regatta held in Oregon, USA. In the UK, regattas are generally between 500 metres (1,640 ft) and 2 kilometres (1.24 mi) long.