Website: wikipedia
Address (car park): Brandy Row, Chiswell, Portland DT5 1AP
Chesil Beach itself stretches from West Bay (Bridport) around to Portland Bill. The beach is exposed to strong westerly winds and tides, which deposit the famous (infamous) shingle along its length. The beach is well known to divers for the exciting entry and exits through surf and steep shingle bank.
Once you are 2 or 3 metres down (normally about 6ft from the shoreline!) there is usually plenty of marine life to explore in the Cove. Wikipedia lists over 40 wrecks in the area, but with the shifting seabed and big storms, it's surprising rare to find any sizable wreckage.