Making an Aubrey/Maturin style knotted rope ornament in LaTeX?

Actually I found a freeware TrueType knots font that has some nice knots. To use this font you must compile with XeLaTeX or LuaLaTeX and have the font either installed as a system font or place the .ttf file in the same folder as your .tex file.

MWE:

documentclass{article}
usepackage{graphicx}
usepackage{fontspec}
setmainfont{EB Garamond}
newfontfamily{knot}{knots.ttf}
begin{document}
begin{center}
Huge
THE YELLOWADMIRAL

vspace{5mm}scalebox{2.0}{{knot R}} % or knot l

Large Patrick O'Brian
end{center}
end{document}

Result with {knot R}:

{knot l}:

If you want to know which letter corresponds to which knot then you could use for example http://www.asciitable.com/ to look up the numbers given in the chart on the font website (in the decimal column of the ascii table), or open the font in FontForge, see the screenshot below for two rows of the character overview window from FontForge.

Note that I used EB Garamond as main font because it looks a bit similar to the screenshot in the question, however this is just for illustration and you can change this to any other font that you like.