I'm wanting to take a boat trip out to see the Maunsell Sea Forts. The only company who seems to do this is the Greta Barge which is a 6-hour round trip http://www.greta1892.co.uk/. Does anyone know of a different way to see the Sea Forts? Preferably by RIB or speedboat, either as part of an organised group trip or private charter? Maybe nothing like this exists and the Greta is the only way!