You are probably going to need a trailer. Do you know the total weight of your boat with engine? My MK2 is around 500lbs. There isn't a capable wheel made for beach launching it. I bought 49cm Wheeleez tyres that I plan on building transom mounts for once a few other projects are out of the way.
Where do you plan on launching?
From 2 pages back here is a thread on launching wheels.
http://www.rib.net/forum/showthread.php?t=39751