New plans to improve Penzance Harbour have been sent to the Department of Transport.
The proposals have been drawn up by Cornwall Council and Penzance Town Council.
The new plans were submitted hours before a government funding deadline which ends on Friday.
The proposals include a scheme to dredge the town's harbour - something seen as crucial if the sea-link to the Isles of Scilly is to be maintained.
Scaled-back plans to redevelop Penzance Harbour and provide a link to the Isles of Scilly were shown to the public earlier this year.
The plans have been reduced from a £65m scheme, which was criticised by the government in 2011 as "poor value for money", to £8m.
Chris Pomfret, the chair of the Cornwall Local Enterprise Partnership, said: "Frankly this has been discussed for far too long.
"We need the improvements of the harbour. Let's get on and do it."
Last year, the government announced it would not help finance the original plan for a new £44m ferry terminal as part of a wider £65m project.
Cornwall Councillor Chris Ridgers, the council's portfolio holder for economy and regeneration, said it was important the transport minister now agreed to the dredging.
The Isles of Scilly Steamship Company is responsible for both the Scillonian ferry and the Skybus plane links to the islands.
Jeff Marston, the firm's chief executive, said: "I'll be disappointed if we don't find a resolution now.
"The operation won't cease if this work isn't done. It would just become more difficult and ultimately that affects everybody and ends up costing more money."
Earlier this week residents on the Isles of Scilly said transport links needed to be improved to the islands when the year-round helicopter service ceases.
British International Helicopters (BIH) will stop its service on 31 October after running into financial problems.
The Scillonian ferry currently runs for only seven months a year and the other link, Skybus, is weather-dependent.