My first thought when I saw your post was be careful!
Sorry to sound like I'm nagging but it might get a bit rocky when a boat passes so make sure there's something solid to hang on to!
Please, as Charlie mentioned let us know what your holiday is like when you return.
My hubby and I are going to Europe in Sept. so would be interested to read of this way of travelling as we're thinking of trying it for part of our holiday.
Best wishes,
Lee