Going without a windspeed indicator is a non issue... it's not a 'must have'.
However I'm not at all sure that the two of you will really work out in the confined, mutually dependant world of a small sailboat....
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
1984 Fast/Nicholson 345 "FastForward"