I suspect nobody does it for a reason. I agree, not sure a prawn would last 10 minutes let alone a 10 mile trolling session.Never heard of it and its difficult to trial because if you troll for a week and dont catch anything, you will be none the wiser!
Certainly a prawn can elicit a huge response from fish in a pool. Maybe a drifter float would be an idea because I dont fancy the prawn's chances of staying in one piece after 10 mins trolling.
i have done it with a team of three spinners many years ago (similar to vibro spoons) About a foot apart and a worm dangling on the end, still very popular in Scandinavia.It was all done years ago. You can troll a worm slowly as well. Osgood McKenzie caught hundreds of trout trolling worms on small lochs with a boat and oars. A Rapala , Toby or Sprat are deadly killers for Salmon trolling. You can still troll for weeks with them on our Salmon Lochs and catch nowt. So if you trolled with a prawn you could do likewise.