The "Royal Mail Ship Athens" was an iron steam screw barque of 739 tons, built in 1856 by Denny of Dumbarton and operated by the Union shipping company. It was wrecked between Mouille Point and Green Point on 17 May, 1865. This occurred at night, after the boiler fires were extinguished by heavy seas during a North-West gale while trying to steam out of Table Bay. The ship had been lying at anchor while preparing for a voyage to Mauritius. The site can be identified by the remains of the engine-block, which is visible above the water. This site is not in a Marine Protected Area. A permit is not required to dive here!
It was Wrecked between to the Promenades of Mouille Point and Green Point may notice; something man-made sticking out of the ocean, less than 100 metres from shore. This artefact is the iron engine block of the Royal Mail Steamer Athens, which ran aground here in the 'Great North Westerly Gale' of 17 May 1865. Seventeen ships were wrecked World-wide, during this colossal gale.
The wreck is very broken up and overgrown with kelp. It is possible to dive the wreck; indeed, owing to its accessibility from shore, it has been extensively “salvaged” in the last 150-plus years! The average maximum depth is about; 7 meters. Although some of the wreckage is very shallow and in the surf zone. This site is not in a Marine Protected Area, so no permit is not required.
References
http://www.learntodivetoday.co.za/blog/2015/03/24/visible-shipwrecks-rms-athens/
https://en.wikivoyage.org/wiki/Diving_the_Cape_Peninsula_and_False_Bay/RMS_Athens
https://underthebluegums.blogspot.com/2016/10/book-takeaways-shipwrecks-of-dive-sites.html
Further Reading
https://resource.capetown.gov.za/documentcentre/Documents/Graphics%20and%20educational%20material/HID_Shipwreck_of_RMS_Athens.pdf
https://www.flickr.com/photos/hilton-t/4929341806/
https://en.wikivoyage.org/wiki/Diving_the_Cape_Peninsula_and_False_Bay/RMS_Athens
https://underthebluegums.blogspot.com/2016/10/book-takeaways-shipwrecks-of-dive-sites.html
https://south-africa.greatestdivesites.com/cape_town/rms_athens
https://sahris.sahra.org.za/sites/default/files/additionaldocs/Annexure%2010%20CCT%20Desal%20Plant%20Granger%20Bay%20History%20of%20the%20Sea%20Point%20and%20Mouillie%20Point%20Promenades%20and%20context%20.pdf
https://www.pressreader.com/south-africa/weekend-argus-saturday-edition/20170513/281728384440085
https://molegenealogy.blogspot.com/2012/05/great-gale-table-bay-17-may-1865.html