Update 1
Firstly, thanks for all the support. It means a lot.
The first two days have not been as productive as I had hoped, although I do only have 1 hour 30mins each night (at best) to work on the game. I thought the easiest part would be moving the ship and firing cannonballs but this has seemed to trip me up more than expected. I have finally managed to implement these, the cannons fire themselves when it detects an enemy ship. I might make this a toggle option for those that prefer to fire all cannons at the same time. I've included a reloading coroutine for each cannon and added a health system for the player and enemy ships.
Over the next few days I think I'll tackle the enemy ships movement (shooting should be sorted, same script with the player) and start the day/night cycle. I have added an image of what I have got so far. As you can tell, I'm no artist, and have gone for the MVP approach. I will be replacing the sprites with actual ships towards the end of the jam and adding a tilemap for the world design.
Happy jamming!