To rbcy1974: one tip.

[alon]

Hi Daniel,
Many thanks for your comment. I actually have one good tip for this excursion.
You can buy the ticket only one day before the excursion, but the sits are not reserved.
I recommend you to get there as early as you can, try to be the first to enter the boat, and catch a sit next to a window that can be opened. Those sits are less than 5% of the total sits, and if you've got a bad one, for example a sit with a view on the toilets, you won't be able to replace it.
I hope you find it useful,
Alon