If you mean would the side keels negate the effectiveness of a side thruster: I think they'd provide some additional drag resistance beyond that engendered by the hull itself; but with the right amount of thrust I think the drag could be overcome.
I've always throught a side thruster in the right place would be a nice addition from the standpoint of maneuvering and functionality. The trick would be hiding it so it's not so visible: maybe inside the tailcone, in a Kort nozzel or the like?
Didn't I read that someone has already done this? Tom's jet NAUTILUS, maybe?
Mounted in the right place, side thrusters could provide the tight maneuvering capabilities I've always wished my boat had when we're getting it back on the trailer. Could enhance turning when underway, too.
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