I did not see any boats using surface drives and wondered why donÂ’t more people use them instead of Bravo or IMCO drives. Arneson makes a conversion kit so you can fit their Surface Drive ASD6 Unit in place of a conventional I/O Unit. One guy replaced his standard I/O with the surface drive on a 18 foot Dozi and went 110mph. It seams like there would be a lot less things to go wrong on the unit.