Mostly I try to keep my opinions to myself, but when I read this posting, I couldn't help but shutter.  Perhaps if I knew your intent, I would feel better.  

Five people in a canoe, any canoe, seems like a risky proposition, especially when it comes to the unpredictability of young children.  (Unless your with a fur trading company from France and its the 1700'S)  I can't keep my 2 1/2 year old daughter to stay seated at the dinner table long enough to drink her milk. I can't imagine what it would be like confining her to a canoe with four other people and fish hooks.  (Poor parenting on my part?...maybe).  

I have know idea what your skill or comfront level is and my intent is not to pass judgement.  Just be careful and remember, "Wisdom is the better part of valor."