[rng_civ]

It's not ambiguous because you have a directional reference built into the phrase and speaking directly to a singular person: "ask you about your left hand".

It is certainly clear if one would say "left facing stern" or "left facing aft", but that's a mouthful when you can just shorten it (and the reference facing direction is not relevant). Bonus points if the shortened version can't be mistaken for another direction...

BTW, I'm 100% down for introducing dedicated words for "my left", "your left" etc vs just "on the left". It would certainly save me a bit of time when my family asks me to look for something and they flip between the two meanings in the same sentence.

[taeric]

This still falls due to you having to have a point of reference for front of boat. See other threads where double ended ones do not have fixed starboard and port.

I am still on board with dedicated terms.