In addition to the Jones Act, commercial divers are protected by the general maritime law and in particular unseaworthiness.
An owner of a vessel has an absolute duty to provide a seaworthy vessel, and a breach of that duty gives rise to a claim for damages.
Here, a commercial diver will have to prove that the owner had failed to provide a vessel which is reasonably fit and safe for the purposes for which it is to be used.
Regarding maintenance and cure, a commercial diver is not only entitled to be reimbursed medical expenses actually incurred but should also receive the proper treatment and care. The dive company is also liable to for compensatory and punitive damages in the event that his employer/vessel owner has willfully failed to fulfill its maintenance and cure obligation.
Furthermore, the Jones Act provides pecuniary damages (loss of earning capacity, medical expenses etc.). One that think they have a Jones Act Case may want to contact a maritime law attorney.