You will probably be better off to get a hotel room with air conditioning, rather than sleeping on a boat, Havasu in the summer can be very HOT, you will want to have a cool place to sleep.
for hotels check: London Bridge Resort -
www.londonbridgeresort.com - (928) 855-4777 -
It is right on the channel, and next to Kokomos (bar), also has boat slips for people staying at the hotel.
http://www.google.com/search?hl=en&i...=Google+Search
Boat Rentals:
http://www.google.com/search?hl=en&i...=Google+Search
You might also want to consider the Nautical Inn, Nice New hotel, on the water, with a beech, has boat rentals right there, right on Thompson Bay, excellent location, lots happening there and right next to the channel.
Nautical Inn Resort -
www.nauticalinn.com - (928) 855-2141
Good luck,
David