It's not the manner of the rowing, it's that it is done when I am already rowing in a straight line and rowing with that third oar throws it off like you wouldn't believe. The single oar method is great for one person in a really small boat, moving along with a current - three oars in an inflatable when one person is already rowing is one oar too many. This is an on-going argument for us.
We've been looking at other types of boats, so someday maybe we'll get the proper type of boat for "cracker" style rowing. But one of those small outboards for our two-person boat would be way cool, to use the vernacular.