After two nights of this, I politely yelled "turn off that f__king light,
please!" Would you believe she asked me why, after the boat was tied up?
And
this was a 65 year old woman with a boat of her own.

#1 - Obviously the person was trying to help, but ignorant. No need to
swear.

#2 - Why wait for three nights, why not simply explain to her that the light
blinds you...on the first night. By not explaining you were
probably
leading her to believe it was helping.

#3 - The person is a woman and 65. Ok, maybe it shouldn't make a difference
but do you really need to yell obsenities at a 65 year old woman?

#4 - Yes, I can believe "she asked why." She was trying to help and was
unaware
that it wasn't helping. Stupid & uninformed, yes. But at least
she's asking
what the problem is so she can learn.

Sounds to me like you knew more but she had the right attitude AND was
willing to learn more.