Up to 25 firefighters are tackling the blaze at the yacht club in Temple Manor Marsh, Knight Road.
It started at around 8pm.
A fire launch boat and the Coastguard are also at the scene.
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More than 70 firefighters have been tackling a fire in a thatched cottage in Longparish, Hampshire.
Police have released CCTV footage of the last known movements of 21-year-old University of Brighton student Janet Muller.
Wednesday night's weather for the east of the region