I have uploaded the PDF I printed out to make the decals for my Prussians. Please fell free to use on your own vessels. To get the white border I printed it on white laser jet paper (actually, I printed it on paper and had a local copy store, photo copy it onto the laser printer) and trimmed the decals very carefully to shape and then applied them.
Hope you find these as useful as I did.
Prussian Cross Decals PDF
17 hours ago