It would seem to me any dumping of appliances on the seabed would need approval of the DOE since the sea floor is public land (as all dock owners already know). When tankers and such are sunk to create artificial reefs it is done in deep enough water that corals can grow on them and in turn become their own eco system. I would think washing machines and appliance parts sunk inside the reef have a very little chance of becoming encrusted with coral and will forever look like scrap metal on the sea floor. Not very appealing in my opinion. I would hope any artificial reef created on the inside of the barrier reef would be made with natural materials. But again, only my opinion.