Just picked up on this thread. Sorry to hear of the latest part of your learning curve.
To answer one of your earlier questions, a "V" shaped bow fender may be a useful purchase. It dangles over the nose and stops the bow hitting the pontoon too hard.
Originally Posted by brucehawsker
Is it the case that if, with a 6.5M rib, the bow and stern lines are at a 45 degree angle in front and behind the rib, in normal situations (minimal wash, shelter) only those two lines are necessary? Or should I always use four?
The mooring cleats on the pontoon/quay will never line up with your boat. One of Sods many laws. If you are leaving the boat unattended, then use springs, always. I take springs as far forward and aft as I can. i.e. from the bow to the pontoon near the stearn and vica versa.
One more point. If you are rafted more than 3 out put additional shore lines from you, over or round the inside boats, to the pontoon. This lets someone on the quay hold your boat securly while those inside slip out. DO NOT rely on anyone re-tying you boat securly. Go and check it regularly. Its a pain but worth doing. Remember how it was done at Yarmouth earlier this year (just before incident 1 & 2).
Old sea dog story. Many years ago I was doing Cowes week in a 32 footer. We were rafted 5 out of 7 on the outside (channel side) of the outer pontoon at West Cowes Marina. At 0730 a Frenchman, 2 out, left. He cast the 5 yachts outside him adrift.
You should have seen the panic.