The two ends of the object seem to be different sizes which to me indicated a streamlined shape. It appears to be oval in cross section and it doesn't seem to be symmetrical so I thought that ruled out it being an oil drum or a mine. It's hard to say what the total size is as half the object is buried in the sand but the razor shells in the photos should give some idea of scale. The top surface is perhaps 4 feet long and it's about 2 feet across at the widest end. Unfortunately I didn't have a measuring tape with me so these are just guesses. It was just a chance find whilst I was walking along the beach.