You can't just scale it up. Motor mount and stern tube will change also then.
Don't try it with PET. It is as difficult to print as ABS.
Only for PET, a friend had to modify it, with additional rails on the bottom and something that should look like a breakwater on deck, to avoid bumps. Even so, it was difficult enough.http://www.thingiverse.com/thing:1377452
Take PLA, this is the easiest way to print it.