online: https://ocelotwalrus.github.io/endless-sky-ship-builder2.0/
This is basically an updated version of https://endless-sky.github.io/ship_builder.html. I added a 'reverse engine button' and a 'bay button'. For now it is pretty basic but I'll work on adding more swizzle options and other things. You can download the html to have it locally and acces it even if you're not online.
Plase if you're interested in endless-sky, check my plugin project!