Coastguard rescue helicopters from Solent and Portland are searching the area along with RNLI lifeboats from Bembridge and Yarmouth in a search for stricken ship which issued a Mayday message.
A British naval vessel is also assisting with the search and broadcasts for all vessels in the area have been made.
There are are winds of between force five and six from the west or south west in the area tonight.
Coastguards coordinating the search and rescue operation have not been notified of any overdue vessels but asked that anyone with information about a trimaran vessel they know to be sailing in the mid channel area call 999 and ask for the Coastguard.
A sea and air search is taking place in the English Channel after a merchant ship reported hearing a Mayday message.
The Maritime and Coastguard Agency said it was contacted at 4.50pm by the ship's crew who had heard a Mayday message on VHF radio from a trimaran vessel in difficulty.
The message asked for urgent assistance and said the boat was at risk of capsizing. It reported the trimaran's position in latitude and longitude to be 37 miles south of the Needles, off the Isle Of Wight.
Rescuers have decided not to resume a search for the missing pilot of a light aircraft that crashed in the English Channel, coastguards said.
An air and sea search was mobilised by British and French rescuers after the American-registered single-engine plane, with one person on board, came down in the middle of the Channel yesterday afternoon, about 15 miles off Dungeness in Kent.
Wreckage was later found by the French search and rescue helicopter, and last night teams worked against the clock to try to find the missing pilot before suspending the search after light faded.
"Having taken the advice of the RAF as well as the French rescue authorities, we have decided that we won't be resuming the search," a spokesman for Dover Coastguard said today.
A French search and rescue helicopter has found wreckage around 15 miles off Dungeness, the Maritime and Coastguard Agency has said.
The spokesman added: "The search and rescue helicopter from RAF Wattisham has now joined in with the search, along with the Dungeness RNLI lifeboat, and three French vessels."
We had reports that an aircraft was overdue. It was heading from London to Le Touquet. It was an American-registered aircraft with one person on board. The search has been involving a French helicopter and it has been searching for two hours.That will have to return shortly and that will be replaced by a search and rescue helicopter from RAF Wattisham in Suffolk.
The Dungeness lifeboat is en route and we believe the Calais lifeboat is also involved. The search is ongoing at the moment to find the pilot. We still have about six hours of daylight left.
British and French emergency teams are responding to reports a light aircraft has crashed into the English Channel.The American-registered plane carrying one person on board came down about 15 miles off Dungeness in Kent at around 2.30pm.
A cross-Channel search and rescue operation has been launched involving both English and French teams, including a French helicopter and the Dungeness RNLI lifeboat.
The alarm was raised after the single-engine light aircraft, which was heading from London to Le Touquet, was overdue, a spokesman for the Maritime and Coastguard Agency (MCA) said
Dungeness Lifeboat Station is responding to reports of a small light aircraft, which is believed to have gone down in water off the coast of Dungeness, Kent.
Dungeness lifeboat launched to small aircraft which is believed to have come down in the water approximately 14.5 miles SSE of Dungeness
The coach who was with Susan Taylor when she died swimming the Channel, said that "total fatigue" was the cause.
She had been swimming for more than 16 hours, covering 30 miles, when she collapsed in the water.
Donations to the charities for which she was fundraising have passed £60,000.
ITV News correspondent Juliet Bremner reports:
Susan Taylor's brother David Wright offered a moving tribute to his sister saying that he hoped her dedication would inspire others.
"We hope that Susan's dedication to promote these very important charities will encourage others to look beyond themselves and continue what she held so dear," he said.
The charity donations for Susan Taylor, a swimmer who died while attempting to cross the English Channel, are now over £59,600.
Mrs Taylor was raising funds for Rainbows Children's Hospice and Diabetes UK.