I boarded the ship the first time after defeating the Jotho League and after arriving in Kanto I immediately went back on it to see if I can use it any time or have to wait for certain days like in Crystal.
Unfortunately I didn't notice that the pier in kanto did not belong to Vermilion City. So now I'm back in Jotho and can't fly to Vermilion City, since I haven't already been there. And to top that my game is stuck on sunday, even so real time clock is enabled and works well for everything except weekdays, so I also can't wait for it to get monday where the ship travels from Jotho to Kanto.
Is there any way to get to Kanto, or get the weekday system working, or do I have to restart?
Use the walk through walls cheat code for Fire Red, then go to Goldenrod City and try to get into the train bypassing the guard. If done correctly you will be automagically teleported to the City of Saffron. Then using the same method you can travel anywhere in Kanto.
Be warned this will ruin the game strory, if you use cheats. You can also try to find any other cheat codes to change the day time for example but I don't know if they exist of how they function.