My Ia Oranas for BB say that there are tenders to the motu the first afternoon, starting around noon, and the second day,looks like it's 10 something a.m. to mid-afternoon.
I'm not bringing a floaty. Just more stuff to drag around. I grew up lying on a towel, I can still do it. Without a balcony, the bathtub's going to be half-full of sandy snorkelling equipment and shoes. The stewards do a good job of cleaning up after you, however, so the bathroom ends up fairly neat and tidy, considering.
There is a floating bar on the motu, by the way.
It's the same motu as the BB Pearl, if I remember correctly, that's why we have to stay "in bounds".