: Pooch size will drive the design - but there's no guarantee the
: pooch will go along with your plans for its ventures afloat.

: To save a new build or serious modification, a small one can safely
: sit in a basket strapped to the deck. and a medium sized one
: might fit into a hatch, but a large pooch will need its own
: cockpit to keep the CoG low, and a bigger boat too.

: I doubt the dog will do its share of the paddling . . .

I can say with absolute certainty he will not do his share of the paddling!

I second the canoe suggestion. I took my 100lb chocolate lab, Moose, on a 43 mile trip down the Colorado river several months ago. We had a great time but that extra 100lbs of displacement was a real chore to push down the river by myself. Moose is 6 years old now and a VERY well behaved dog. Spend some time working on basic obedience, specifically sit, lay down, and most importantly stay and you will have a great paddling companion! I have also found wearing him out with a spirited game of fetch before we got underway to be very beneficial.