squadron comm 221113QF2 Brisbane is pleading for people to "respect the sea" after an all night search for a missing swimmer uncovered a body. It was the fourth death in southeast Queensland waters in five days.

The body of a young man was found on North Stradbroke Island in the early hours of the morning after an air and sea search was launched at around 8pm the previous night following his disappearance.

He had been swimming with two friends off Flinders Beach when a thunderstorm hit. His two friends managed to get to shore and sound the alarm but the third man could not navigate the choppy waters.

Coast Guard Brisbane, based in Manly on Brisbane's southeast bayside, sent 12 volunteers and three boats to join the rescue helicopter and two police boats patrolling the waters.

Previously, a 23-year-old sailor died in Waterloo Bay off Wynnum on Saturday. The man had been sailing competitively when his 18-foot skiff capsized in a freak accident. The sailor did not have the clip on his safety harness attached and when the boat flipped over it clipped itself onto the vessel's "trampoline", trapping him under water.

No-one on the boat could cut him free and depite the efforts of the Coast Guard, he was dead by the time he was pulled from the water. On the same day a 22-year-old man died when his jetski collided with a boat in the Coomera River at Paradise Point on the Gold Coast. He could not be resuscitated.