Endicott was injured aboard an icicle foods vessel (the lowercase is evidently intentional). He brought the case in state court. Under the Jones Act:
A seaman injured in the course of employment . . . may elect to bring a civil action at law, with the right of trial by jury, against the employer. Laws of the United States regulating recovery for personal injury to . . . a railway employee apply to an action under this section.
Endicott argued that this was his choice. icicle contended either party could demand a jury. The question comes down to whether the law of the venue or the law of the action (in admiralty) governs. The Ninth Circuit Court of Appeals follows the law in admiralty, which leaves the right with the plaintiff (along with California). The 5th and 7th circuits follow the law of the venue (along with Louisiana and Illinois).
The court adopted the jurisdictional reasoning. Of particular note is their interpretation of a 9th circuit opinion talking about the Jones Act being cause of action oriented even thought that circuit has said the right flows to the plaintiff.
Substantively, I have to comment that its a way to erode the protections given to Maritime Workers under the Jones Act. In the age of tort reform, where the burden is stacked against a defendant legally, providing a jury trial for the defendant does nothing but break down the stacked deck that was put in place by the legislatute.