Steamliners to Macau

I would like to add a comment, in fact a question, to the thread on "Steamliners to Macau" which is now rather an old forum. I have been trying to find some information about a ferry, probably but not necessarily a Hong Kong-Macau ferry, called "Pao Kee" which was lost at sea in July 1971, and I wonder if any reader knows anything about it. An old friend of mine was mate on board her when she was on a delivery voyage, under tow, from Hong Kong to India to be scrapped. She, and her tug, put into Cam Ranh Bay in Vietnam because of bad weather. She sailed out again and disappeared, and so did a few other ships. The assumption is that a Vietcong frogman put a limpet mine on her hull. My friend was never seen again. I have only recently learned the name (though the spelling may be wrong) but I have been unable to find out anything about the ship and her history, or any more information about her loss. Can anyone help? Best wishes, Peter Wadhams, Cambridge, UK. email p.wadhams@damtp.cam.ac.uk.