With the weight etc of RIBs today it is essential that you use 'hard' tie down points, it is no use going over the tubes with straps and expecting the boat to stay put for any length of time.
If you have them the ideal tie down points at the stern are 'U' bolt towing points on the transom, and at the bow the u bolt for the painter? A single strap at the front will suffice , to stop the boat riding up over the bow snubber, one or two straps at the stern can be used, but use good quality cam type tie down straps and do them up tight!!
Dust creation specialist