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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A further 85 buses are expected to arrive on Tuesday and Wednesday, with officials saying the entire operation will last at least a week.
The government will make an announcement about whether Heathrow or Gatwick should be awarded a new runway at 12.30pm today.
Tuesday morning's weather for the west of the region