Doug,

It was a bit more than 40 years ago (not much) and the rental was $2 for the morning, $4 'til sunset. That got you a flat-bottomed, flat-ended scow, two oars (occasionally the same length), a bailing can (necessary), an anchor made of cement in a large coffee can... and total freedom.

Ah, the memories. What is more, once you learned to row that barge, any decent pulling boat was a dream.

Go for the pram and don't worry about windage or weight, that's why we have kids -- if they don't serve as ballast, use them as oarsmen.