What is the procedure for filing a OWCP claim - longshore & harbor workers' compensation?

I agree it sounds like you are a seaman covered under the Jones Act and General Maritime Law of the U.S. I also agree that you should contact a lawyer who specializes in admiralt/maritime law to determine which law you are covered under.

However, in order to file a claim for compensation under the Longshore & Harbor Workers Compensation Act, you should complete (as best you) can a Claim for Compensation (form LS-203). You can dowload the form from the U.S. Dept. of Labor's website at: http://www.dol.gov/esa/owcp/dlhwc/lsforms.htm

You will then need to determine which Compensation District in the U.S. the Claim for Compensation should be submitted to. Review the map on the Dept. of Labor's website for the office that covers the state where you live. The web address is: http://www.dol.gov/esa/owcp/dlhwc/lscontactmap.htm

It sounds like you may be subject to a seaman's injury claim and not a longshore and harbor worker's claim--so you should consult with an attorney who handles both types of injuries.