Yes, I can understand why spending a night tied to these commercially oriented dolphins (see below) would not make for a very comfortable evening. In addition to the solution provided by Captain Mikki below, another good plan would be spend the night at Roland and Mary Ann Martin’s Marina (in Clewiston).

The dolphins at Clewiston are really for big tugs, not 36′ trawlers. That was our planned stop to be ready for Lake O in the morning. We tied bow and stern up using the dingy but, just at that time there was rain and some wind, so it made it challenging to be safe for the night. Safe we were and got an early start in the morning for a good trip. Next time I’d like to try anchoring in Moore Haven and crossing Lake O and anchoring just after railroad bridge where a canal makes a cut.
Mikki
on Asian Lady

And, a very different point of view:

We have tied to dolphins on the Big O waterway several times. We found that they are an excellent place to spend the night. We use a stern anchor to eliminate the swing, rather than trying to tie to a second dolphin. Most of the posts have cleats, but a few don’t. Watch for an excess amount of tar on some.
Richard Ross

Click Here To Open A Chart View Window, Zoomed To the Location of Clewiston and Roland and Mary Ann Martin’s Marina