I have seen some boats to have a bracket (similar this for auxiliary outboard )for reach the main outboard away from stern for about 1 ft .Why they do that and what is the gain? Maybe for cavitation?
Allows them to have a full transom as opposed to a splashwell which is safer for off-shore boats. Also frees up the deck space that the splashwell would have taken up. I believe there is also a performace improvement with a bracketed outboard.
Like EZ said, having a full transom without a splashwell is the big reason. Having a bracket allows for more storage too. Some of the really nice full length brackets have swim platforms and boarding ladders built in.
