So I se about making the ditty bag from "Sail Makers Apprentice". I had a few goofs, and I could not easily source brass thimbles, so I just whipped the cringles instead.
Given the length of time it took to make a simple canvas bag, I am quite glad that I simply bought my sails rather than tried to sew them up by hand.
It was very hard to make up a grommet in polyester the size of the bag. Retwisting the strands as you go is a must.
You also need to use some sort of bobbin to wrap the whipping thread around or it will take all day to do cringles and loops.
I am considering waxing the canvas so that I can actually use it rather than just have sit on a shelf. It's full of sail sewing kit right now. Hopefully I won't ever find myself needing to make repairs to get me home. I also think that I will get a big roll of self adhesive sail repair tape too.