Angry members of Brighton Marina Yacht Club will hand over more than 100 letters opposing £100 million plans to transform the site.
They will hand them in on Friday, just in time to beat the deadline for submissions following a public consultation exercise.
Parkridge Developments has drawn up proposals for new buildings, including bars, restaurants, shops and extra housing.
But opponents believe the scheme would add to parking problems they already suffer.
Club president John Duffy is also unconvinced by promises that a permanent yacht club headquarters would be provided.
The club is based in a portable cabin, its fifth temporary premises in its 25-year history.
Mr Duffy said: "I find it difficult to know how they can include a yacht club without speaking to us and finding out what we want."
Parkridge managing director Philip O'Callaghan has said the changes would vastly improve the marina for yacht-owners as well as other visitors.
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