The issue of short-term letting was briefly discussed at the meeting in the light of recent news that people who let their properties during the Olympics could be fined. See e.g.: http://www.bbc.co.uk/news/uk-england-london-15083506.
Also, according to the consultation paper on the current planning application, the effect of the development on the value of one's property is not a “relevant planning consideration” and will not be taken into account as a valid objection.
This website: http://www.greenland2012.co.uk contains lots of inspiration for a written response even from those residents who may have no particular objection to a temporary marina but would be strongly opposed to a permanent facility.