David25, Your friend was pulling something when he mentioned the...

David25, Your friend was pulling something when he mentioned the pumping of water in and out of the boats.
All pipe work has to maintain pressure inside and outside at the maximum depth. plastics is not used on hull fittings or any pressurised systems. All pipe work is x-rayed, and pressure tested prior to installation, I know having worked in that excuse for a shipyard for ten years. The pipe work he may have been talking about may have been low pressure stuff, nothing to do with the actual boat, a small tank for catching drips from test equipment!!!!!