Swifts were on the way out, at least in Reg. 10, when I was a novice in '65, but I remember seeing a Big D on the beach at Long Lake, light blue IIRC, with a Mk75 on the back and six megaphones. The top pipe pointed straight back, but from #2 to #6 each pipe had to angle down more, until bottom pipe looked like it would almost drag in the water. Good days, wish I had a photo.