A quick search through ebay revealed a couple - I paid £29 for mine - here is what looks to be the same - http://cgi.ebay.co.uk/Tug-Boat-Model...QQcmdZViewItem
It does have a water cannon, but my pump doesn't work very well and just pumps water into the hull unfortunately.
There is a small tank in the hull which fills with water and acts as ballast - it does work fine, but when you turn the boat tends to heal over, and unfortunately yesterday, the string (sorry, rope) caught it at that moment and over she went.
I've just been told that after a quick dry, the boat is working fine again
With any luck, I'll replace the electronics in a month or so with digital proportional controller to get better control out of it - there is space for a couple of Schottel drives in the back too which would give even better handling....