Dory motor well

[limbrat]

I think about building a bigger dory than i have now.(there addictive)
About 18 foot with a 48" bottom and 62" or so inch beam. If i build a motor well for a 3 or 4 hp motor at about 5' from my transom in my bottom panel will i need to make a tunnel out the rear, or will the natural sweep and narrow transom handle it?