I departed my frigate to go to Lord British's castle in 1423 BC to get some healing. I exited the castle and let time lapse and no time gates showed up... but I finally figured out that there are no time gates for that island in 1423 BC and you lose your blue tassle when you exit the boat.

No respawns are showing up on the island.

Am I in a restart position or is there a way out of my predicament?