Just my 2cents.
If you just WANT a portapee on your dagger, you have to take a little time to get the LOOK. A navy is the hardest to get right.
If you get the right knot, and wet it a little to get her to streatch, she will shrink on drying to the look you are trying to get.
Some knots come with the look built in. There are several on the web now for navys. A little moisture, and you have it.
She looks super now. but if you just have to have a knot, try it. Or leave it.
Ed