B & M introduced a shiftable marine trannie in the mid 90's. Its intention was to have a low gear to make a big propped boat more manageable around the dock. It had a 2.2 reduction in reverse. I installed a pair of them in a 32 Hustler with 572 tunnel ram motors and #3 speedies. Seemed to work OK. Boat ran a little over a hundred. Must have been in 1995.

Never saw or heard about them ever again. Seems they never caught on.