Just a comment and perhaps a sign that I don't understand something. For me, 15 kts. is enough to make holding the boat boat difficult, especially when it gets on the beam. Lots of the suggestions, perhaps most, will work just fine when the wind at the pier is 5-7 kts., but I believe that many of the above suggestions aren't just going to do it in 15 kts. Perhaps others 15 kts. of wind is different from mine and a bit more gentle.
I have the same sceptacism when I hear of people "adjusting the
lines" in severe storm or near hurricane conditions. Slacking off
lines, yes, but taking in lines against high winds....I don't think so.