Here is a tikz
version which automatically gets you all the flexibility inherent in tikz
such as rotating the symbol to be appropriate for the axis, adjusting the line style, colors, arrow style, etc...

Further Enhancement:
- Automatically rotate the symbol to be along the path.
- Provide a style setting that can be used to customize the symbol
Code:
\documentclass[border=2pt]{standalone}
\usepackage{tikz}
\newcommand{\AxisRotator}[1][rotate=0]{%
\tikz [x=0.25cm,y=0.60cm,line width=.2ex,-stealth,#1] \draw (0,0) arc (-150:150:1 and 1);%
}
\begin{document}
\begin{tikzpicture}
\draw (0,0) -- (3,0) node [midway] {\AxisRotator};
\draw (0,0) -- (0,-3) node [midway] {\AxisRotator[rotate=-90]};
\draw (0,-3) -- (3,0) node [midway] {\AxisRotator[rotate=60]};
\end{tikzpicture}
%
\begin{tikzpicture}
\draw (0,0) -- (3,0) node [midway] {\AxisRotator[x=0.2cm,y=0.4cm,->,densely dotted]};
\draw (0,0) -- (0,-3) node [midway] {\AxisRotator[x=0.2cm,y=0.4cm,->,rotate=-90,blue, dashed]};
\draw (0,-3) -- (3,0) node [midway] {\AxisRotator[x=0.2cm,y=0.4cm,->,rotate=60, red ]};
\end{tikzpicture}
\end{document}
You should separate input and output. If you want to print a symbol you at first need a font which contains it. If you want to use normal latex (it will work with xelatex too) you can e.g. use the dingbat font to get an anchor. If you want to use the symbol in the input you must declare it (I'm not sure if the ⚓ copy& paste correctly):
\documentclass[12pt]{article}
\usepackage[utf8]{inputenc}
\DeclareUnicodeCharacter{2693}{\anchor}
\usepackage{dingbat}
\begin{document}
\anchor ⚓
\end{document}
With xetex you can use e.g. dejavu sans (if you get the wrong glyph:make sure that you have only version of dejavu sans). Here too you can use commands/other notation if you don't want to use the symbol in the input:
\documentclass[12pt]{article}
\usepackage{fontspec}
\begin{document}
{\fontspec{DejaVu Sans Condensed} ^^^^2693 \char"2693 ⚓}
\end{document}
Best Answer
Similar to Christian's answer, but
siunitx
will deal with the correct typesetting, be it text mode or math mode.