Sea kayaks are designed for use on flatwater as well as out in the open sea. Generally they are around 5m or longer and have an upturned bow allowing them to deal more effectively with oncoming swell. The sea can be unpredictable and so it is always advisable to get some formal tuition before taking your kayak out to sea. A true sea kayak should always have fore and aft bulkheads for buoyancy and all round grab ropes (deck lines) in case of capsize. One should never paddle without a PFD, especially out at sea.