what would be the youngest age you'd take a dog on a boat....by "boat " i mean a small fishing boat not the QE2!!!

We've taken a few of our dogs on my brothers boat, but we've never taken a pup, they have always been over 24 months when they are pretty much well enough trained to do as they are told, are calm enough not to want to jump over and run around tripping people up, good with recall, sit, down stay, I wouldn't take a dog that was not calm and pretty much trained it can be too dangerous, especially if out at sea, and even so they have always worn life jackets. :-D

We took the boys on a narrowboat at about 4 or 5 months, but of course they're rather more stable than fishing boats!

We have always taken our pups out at around 4 months on the rig to start water training.
But we are in the water with them and they are wearing their life jackets.

Peanuts

Would depend on the dog wouldn't it?  We were planning a canoe trip with Jet when she was six months as she was very good in the canoe.  It didn't happen because the cat got sick.  No way I'd canoe with current Puppyboy and he is 8 months.

ditto peanuts,
we start our boys water trainning around this time too.