It might quite expensive to be build as the website states that there '1000s of tonnes' of mud to be removed from the bay. Not a good way to start, by making your own hole in the ground.
Good luck to them, hopefully the government could help with finance for tourism purposes. From the website: -
The report however makes it very clear that further detailed engineering studies are required to determine issues such as hydrographic and geological conditions, since only once these are known can the final project design to be drawn up. The existing design, as attached to this web page, must therefore be viewed as conceptual at this stage, and subject to significant potential changes in scale and/or layout.
An example of the evolution of project design is that Scottish Canals have in principle offered the use of their existing buildings for reception and facilities. These buildings will in effect be restored to better than existing condition, and importantly there will be no requirement for new buildings on the seaward side of the railway track. Similarly the original concept of utilising the narrow strip alongside the railway track as a boat and trailer park has been superseded, the intention now is to reserve this for access and maintenance only.
Wouldn't they be better off re-opening the facilities they have closed further into the Caley canal, such as at the Inverness end next to the last bridge? Word from the loch-keepers last year is a story of consistent under-investment in maintenance (we saw part of a canal side being shored up).
Anyway if you multiply up the cost of those toilets at Crinan to a new marina you are talking tens of millions!