Originally Posted by steco1958
And the difference between towing on a trailer with the engine attached, and say, using the actual boat on water, is what ??
A legal statement at most. Common for most things now. Sure it's fine to tow with the engine but with that notice they are now not held liable for anything when the boat is out of water. That is all it is.
Start thinking of things in legal terms, risk and liability instead of with an engineering concept and then you will see how manufacturers, suppliers, etc try to squeeze out of commitments, warranties and guarantees.