1) Shipwrecks and salvage in South Africa by Malcolm Turner
2) Shipwrecks of the Western Cape by Brian Wexham (Little tip pay close attention to mentions of Brian Clarke, Gavin Clackworthy)
3) University of Cape Town UCT online library will give you good referances.
4) The same for the South African Maritime Museum.www.rapidttp.co.za/museum/
5) Bredarsdorp Museum (shipwreck museum)
6) Charles Hocking Dictionary of disasters (strangly seems to cover this coastline well)
7) National Archives (Cape Town only) www.national.archives.gov.za/
This should be a good start also the local newspapers "The Argus" and "The Cape Times" carry many pictures and articles.
Remember this will only allow you the basics as with any research "if its easy to find - its already gone"
Hope this is of help.
If you find something of particular intrest let me know and I may have more info (I cannot garantee I will be willing to part with this info but I could save you a lot of hassle in letting you know if its already been located and/or worked)