I owned an 18' sea dory for quite awhile, 4 years and it did just fine. They draw as much water as a flat bottom and will run in the same.
They are flat bottom and just have a little rocker up front. ( the earler models that is ) The boat handled well.

For the price you will probly be paying for it, I don't think you could go wrong.

The boat would not be as good for the saltwater, but would work, as long as it is not too rough.