Here is an ad for counter rotating Yamahas
http://adcache.boattraderonline.com/6/9/8/71807098.htmand there are a few here
http://www.alterscale.com/Of course they are models
So I know they exist. My Burns reads 36000 NET on the hull near the port engine. The Vs handle wonderfully. The pilings are still set for my old boat so I just barely clear. I have maybe 3 inches on either side. I have taken it out three times. I have yet to touch the piling when docking. Of course all three times I have come back on one engine as I still don't have the port engine straight and of course the generator is still dead My only point was that twin Outboards MAY be better to maneuver than a single I/O but I would still buy a thruster rather than go through the expense and hassle to modify a boat when the result will be:
The same speed
Less fuel efficient
Lower resale value
So I am on your side for sure.
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