The author of an open letter to Trevor Osborne urging him "not to permanently ruin Porthleven Harbour’s future" has spoken of the "amazing support" he has received since it was published a week ago.

The letter, written by John Boyle and countersigned by Philippa Mina, Alan Richards and Andy Wallis, was posted on Facebook and has since had almost 300 "likes" and been shared 160 times - although Mr Osborne has defended his plans.

In it foursome speak of their fears over the effect Mr Osborne's proposed 'innovation building' in the shipyard - to house studios and units for around 70 people, as well as an internet cafe, public toilets and showers - would have if given planning permission.

Mr Boyle, a retired solicitor who until recently was a director of the Cornwall Marine Network, said: "This application is clearly one on which the village feels very strongly in opposition. Not a single person has disagreed as far as I can see. And one marine business covering Devon and Cornwall has already said to me that they would relocate to a shipyard as proposed by me."

In the letter they wrote: "Like many others we are deeply opposed to your proposed development in the shipyard. Many of your schemes that have resulted in the restoration and revival of derelict buildings have been admirable, but sadly this one is not – it is a new build with serious and far reaching implications that you do not seem to have considered."

Claiming there there would be "undoubted long term damage to the future of the harbour and the village", they added: "We are sure you’d agree that it is not reasonable or fair for one person’s vision for a community, both the physical structures and the way of life, to be imposed with such irreversible consequences for so many people.

"The reality is rather than genuine job creation you will simply be shifting existing tenants into this building and trying to attract other existing businesses there."

They spoke of their fears over car parking, pointing to the "chaos of the limited public car parking" over the summer and continued: "Yes the shipyard is currently a mess, but only because you have allowed it to become so – cynics may see this as part of a larger plan. Areas previously used for boat storage and maintenance have been chipped off as sacrificial offerings to support your other business and development interests."

It was the future of the shipyard that was the main concern, however, and they added: "Put simply, you build this and there is no future for the use of the shipyard as a shipyard. This huge building and its ancillary parking and access requirements will seal the fate of the shipyard forever."

The authors argued that in the past the shipyard had been a "genuine asset" and could again be a "vibrant marine hub" with secure boat storage, small commercial units for trades such as marine engineers and fibre glassing, a permanent home for the gig club, small scale boat building and repairs and reserved parking for "genuine harbour users."

They also suggested a home for the stand up paddle boarding and kayak rental business, and even a surf lifesaving club.

The quartet believed that the building would prevent emergency storage of vessels ashore and also inhibit the annual gig day for which the shipyard was "essential for preparation."

However, Mr Osborne told the Packet: "The letter isn't exactly accurate. The building that I'm proposing is a very small part of the total area of the shipyard - it's footprint is 7.8 per cent of the area.

"We're proposing to create an environment in which artistic and creative start-up businesses might flourish. It is intended that it will bring employment to the village."

Regarding the question of car parking, Mr Osborne said he intended to create parking at Tolponds that "will be more than required for the project."

He continued: "The next question is, 'Will it affect the character of the shipyard?' The answer is no. In the whole of the 40 years that I've owned the Harbour & Dock Company we have never needed to accommodate more than 15 boats laid up at any one time."

The new car park at Tolponds would also be able to accommodate boats in the event of another disaster such as the 2014 storms, he added.

Responding to the "marine hub" suggestion, he argued that almost all the moorings were taken anyway.

The chandler that used to operate could not find sustained work, but anyone who wanted to repair or build boats should approach him and he would "make provision" for them, as he would continue to do for the kayakers and windsurfers.

Mr Osborne also claimed: "I did offer to build a surfing clubhouse 20 years ago and there was objection to it, so it was not proceeded with."

He concluded: "This is not a commercial decision. It's a decision that is made out of my concern to continue good stewardship of the centre of this village."

A decision over whether to grant planning permission will be taken by Cornwall Council on September 28.