On the US
East Coast the vast majority of the transient mooring balls we have seen or used come with an attached mooring pendant. Usually they are quite long at around 10-12 feet (-/+ 3M for the IMD or Imperial Measurement-Disadvantaged.)
I think that most of these moorings have been designed around using that extra
scope and hooking directly to the ball itself may cause issues and the mooring possibly dragging and/or pulling up. I have seen the moorings at NYC's 79th street boat basin drag to the point where the orange transient balls were coming up against long-term
lease moorings. Too short of
scope plus the ridiculously large wakes of the NY
water taxi boats doesn't help especially when a larger
displacement boat is on them even if they technically meet the boat length limits.
If one is using a longer pendant to tie your own moorings to then the only cure is having a bumper around the ball. When we lived in Chicago most of the people on mooring balls in rhet Chicago harbors system would use a half plastic 55-gallon drum over their mooring ball with pool noodles for padding zip-tied around the top perimeter of the drum.
In the
Great Lakes and in
Canada the use of an included/supplied pendant is much rarer we have found in our travels. In those cases you use your own bow lines or your own bridle/swivel system. Your
photo looks like a good idea in those cases if one has a
bowsprit or roller that sticks out far enough like yours.