(g) The sidelights of a power-driven vessel shall be placed at a height above the hull not greater than
three quarters of that of the forward masthead light. They shall not be so low as to be interfered with by deck lights.

from https://www.ecolregs.com/index.php?option=com_k2&view=item&layout=item&id=118&Itemid=499&lang=en

That is because of the height of het fore top-light, i.e. height of fore-mast.
There is a correlation in height of the placement of all navigation lights.
I do not have the exact figures but her sidelights has to placed lower then her fore top-light, which itself has to be lower than aft top-light.
Chee

Why is here navigation light placed on that platform under the wing? Seems like an expensive addition for a place to put a lightbulb.

Martin nice photo of crude tanker

Re John Young-Only pic???