I can't remember if I bought these myself or received them as a present but they're better than they look.
I wouldn't recommend paying loads for them as you can get them very cheaply from various stores about but they've proven to be tougher and more fun than they may first appear.
We have 6 boats in total and we've used them to help my son with his colours (where's the green boat?), and with his co-ordination in stacking them up (they'll only fit together one way). The only thing that frustrates him sometimes is that if they're stacked together when wet it can cause a bit of a vacuum making them hard to pull apart so mummy or daddy usually have to help with that.
They've kept him entertained during many baths and probably for many more to come.
Not necessarily his favourite bathtime toy, but certainly one that's been played with and worth the money.