The sails on your ship can block your vision during combat. If you want to make them invisible, then you can check out this guide at Seeking Tech to see how you can properly do so.
1. Open the Settings menu if you haven’t done so already.
2. You should be in the Gameplay tab, where you need to scroll down until you see the Dither Sails in Combat setting. It should have the following description showing on the right side of the screen:
Determines if sails should be dithered (make see through) when in combat using the external camera.
3. Make sure that the Dither Sails in Combat setting is set to On.
4. Exit the Settings menu.
During combat, the sails on your ship should now be invisible.