A new 400-berth marina in Swansea would make the city the sailing capital of Wales, its backers said on Wednesday.
The Prince of Wales Dock could house 400 boats and yachts
The Welsh Development Agency (WDA) has lodged plans to turn the Prince of Wales Dock into a haven for yachts.
A lock tidal basin would be created along with a new channel linking the dock with the existing waterways.
It would almost double the capacity in Swansea and help the WDA achieve its target of making water sports worth £224m to the Welsh economy by 2010.
The Prince of Wales Dock is at the heart of the £200m SA1 plan scheme to transform the former docklands with a mix of residential, commercial and leisure developments.
It is on the opposite side of the River Tawe to the existing marina and when complete would take the number of berths in Swansea to over 1,000.
The first phase would be a £2m Welsh Assembly Government financed engineering project to create a tidal basin where boats would gather before entering the lock.
The rest of the marina would be paid for from the sale of land in the SA1 scheme.
WDA director Steve Piper said: "It will not only be a key attraction in its own right but serve to enhance the entire development."
The assembly government's water sports strategy aims to increase revue from the sector by 40% over the next five years taking its annual contribution to the Welsh economy to £224m by 2010.