Well, the first time
my dog went swimming was because I
dragged her in!!! LOL....... (I could always tell she
wanted to also, but she was scared to make the 'plunge' on her own as well.) She swam
immediately back to the boat (3-feet away!), but she DID swim......so I tried again, but held her up by her belly longer and longer with each try, and from further & further away. I always had a close hand by her, only inches away from the underneath of her body at any given time. Also, I did it in
very shallow water, so that even if something DID go wrong, her rear legs could 'touch' the bottom.
After the 3'rd trip out on the boat, she loved it SOO much that I had to keep a
close eye on her, as she would jump in all by herself!! She DID learn to
'wait' until
I was ready to go in before
she could. But she would spend her 'waiting' time pacing back & forth on the dive platform, looking back at me like, "Aren't you ready
YET?!"
She spent the rest of her life swimming whenever she got the chance!
Good luck!
MK
P.S. If you're nervous about the first couple of times, you could get her a life jacket........they make them for dogs! They even have a convenient 'handle' on the back to make grabbing them a little easier!

Xena had one, but never liked it or needed it........so now it sits in a storage compartment on my boat!