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tedious,
Well may be true. If you hit a rock hard enough it won't matter...like this. Neighbor on a nearby island hit this shoal just in front of my dock, and tore off his lower unit. I towed them home, then had to give the party of 7 a ride to the Marina and their cars.
Later I dove down where I thought they had run aground, and found the lower unit torn off.
https://www.flickr.com/photos/5818056...0513516031

This was a 200 HP Mercury at full throttle , getting up on the plane, when I heard this sound like a car crash!