Sweeper Cruisers
 

Having finished SH5( disappointing end of the sim) I decided to start from the beginning, following different missions.

I have gone as far as finishing South Atlantic Convoys & sank 3 out of 5 Winstons Specials, now the game has come up with Sweeper Cruisers.

I have used a series of box pattern searches, even "lawn mowed" the entire search area both North to South then East to West 3 times each & still cannot find the 4 cruisers.

Has anybody found these? if so, where is the best location to search for them?
Thanks in advance