gtflash - At the moment there are 2 classes, the one is single 200 hp outboards or inboard deisels of around 330 or 350 hp (rules may change on that soon), the other class is for twin outboards of around 200hp each, with a diesel equilavent as well. There is also a smaller class which has died a bit of a death recently, which is based around the 1.3 litre engines.
A good website to start with would be http://www.biboa.com,
they govern the RIB side of things and are incredibly helpfull people. The RYA are at http://www.rya.org.uk/
As far as stepped hulls are concerned there has been considerable discussion about this at http://www.boatmadforum.co.uk/showth...0&pagenumber=1
unfortunately the thread was started by a Greek bloke with an overactive imagination who has already been banned from here, but the general concensus (including mine as a builder and racer) is that having a stepped hull has nothing at all to do with turning boats over, it's racing and the overenthusiastic driver that is the problem!
Stepped hulls are very popular and do go faster, so you make your choice. Have a look at the websites listed at the BIBOA site for manufacturers of race boats and ask them about lessons. We would be prepared to help with the learning process (www.bananasharkracing.com
) although we are in South Devon, and I would imagine there are other manufacturers who could point you in the direction of someone helpfull.
Good luck and feel free to ask more questions,