My mount is aluminum and seems very sturdy. I use a 5 hp mercury.

::
::
:: I know of a case where the tube cracked from a heavy
:: person fooling around and sitting on the motor. If you
:: go to a heavier motor it would be a good idea to use
:: some epoxy and fiberglass tape to reinforce the tube
:: (crawling to the back of the boat and wrapping and
:: epoxying the tape around the outside of the tube).