Adam Clarke on Acts 27:43

Willing to save Paul, etc. - Had one fallen, for the reasons those cruel and dastardly soldiers gave, so must all the rest. The centurion saw that Paul was not only an innocent, but an extraordinary and divine man; and therefore, for his sake, he prevented the massacre; and, unloosing every man's bonds, he commanded those that could to swim ashore and escape. It is likely that all the soldiers escaped in this way, for it was one part of the Roman military discipline to teach the soldiers to swim.