I need to hire a boat for 6 pax for a Saturday pm. (Amsterdam)

Does anyone have any ideas or experience in hiriing a boat?

I have some friends coming over for the weekend of the 7th aug, and thought it would be great to cruise the canals with a picnic in a boat. There's 6 of us, so it doesn't need to be a big boat.

I'd like to avoid having a 'driver' with the boat, because I want to drive :-) (I have yachting/general maritime experience). Is it possible to get a boat without a driver?

Any ideas on where to start would be greatly appreciated.

Thanks in anticipation,

D.