Boat renewable energy from tidal current (paddle wheel)

I run a small scuba diving operation for tourists, based in Indonesia. Our boat sits permanently on a mooring in the middle of a strait between the mainland and an island and there is a constant, strong tidal current running. Currently the boat uses a lot of energy, in the form of diesel fuel, to run its main engines and electricity generators. As we aim to be a responsible tourism operator, we wish to reduce our carbon footprint and operational costs, so we wish to explore a practical way of doing so. The thought we'd had is to somehow attach a paddle or "current kite" to the boat, to capture energy from the movement of the water, similar to how the water wheel on an old granary mill works. We'd be grateful for advise from someone who has the qualifications and experience of previously managing such a project. We're a tiny company and don't have much money, but maybe this is a project that would appeal to someone who just wants to make a different to the planet, or is a scuba diver and would therefore be willing to barter his/her work for our services.