This thread from almost 2yrs ago may be of interest. In it I doubted the need for long oars... in fact grumbled about rowing a SIB far at all. But good on SteveM for kitting his SIB out to suit his need to row from time to time. He bought 6ft 5in oars.
http://www.rib.net/forum/f50/aerotec...gth-67399.html
By chance last year on holiday there were wonderful shallow areas with wildlife interest where gently rowing would have been my choice. My crew never seemed to get the hang of paddles!
My Aerotec has its standard telescopic paddles which are rubbish. I will either replace them with longer wooden paddles or oars.