Standing on the bridge of his frigate, the captain wearing his Napoleonic uniform surveys the battle raging around as his crew fend off Engl...

Great scene! I find it's a struggle to get historical clothing right (the models, for whatever reason, cannot do Regency clothing. They do better with 20th century fashion styles). You could try starting off with a start image. Even taking what you have and drawing on revisions in photoshop or another editor, then feed it back in as a start image with the same prompt. Even if your drawing is a bit blobby it can still make something worthwhile out of it. I draw stick figures and blobs of colour to get the basic layout of an image that I want and it works reasonably well. I also recommend turning off prompt magic if you want something really specific.