After a great day of fishing and beautiful skies and water the "Pass Time" was heading in from the edge SW of Destin at 4 pm with a box of fish, trimmed up at 38 mph and without a warning of any sort the lower unit on my single 225 Yamaha thumped and then quit turning. Dead in the water 20 miles out...what a helpless feeling.A hail to the coast guard recieved no response but the Captain of the "Plumb Wet" going into Pensacola did respond. Thank you! He was kind enough to relay our coordinates and situation to the CG for us until they managed to home in to our position and pick us up. ThanksCG formaking that phone call to my son to let him know I was ok.I don't know what the problem with my radio was as we had a good radio check earlier in the day.CG relayed our request for tow to Tow Boat US out of Bluewater bay and at 8:45 pm we were hooked up and it tow. Tired and beat up and a little chilly but on the way Home! Made it safely to the boatramp at cinco at 12:45am this morning. MANY MANY THANKS TO PLUMB WET FOR THE RELAY, THANKS COAST GUARD DESTIN FOR A GREAT JOB, AND THANK YOU ELMOS TOW BOAT US! Thinking how much differently the outcome of this situation could have been if the sea conditions and weather would have changed...we are all very Thankfull.