There are not a lot of simple answers.

Our Endeavor 32 steers itself very well too windward if you roll up
the jib in a strong wind. It will also tack, once. I discovered
though that this is only true when you have been sailing with the jib
and roll up the jib without losing much speed while the boat is moving
fast. The main is sufficient to keep the boat moving enough to stay
in balance.

If you let the boat stop, or try to get it going from a stop such as
casting off a mooring, it can't get going fast enough under main alone
to reach the equilibrium where it will sail itself. You will also
lose enough speed in the first tack that you can't tack again or get
the boat sailing itself. Even bearing off and heading up won't get it
up to enough speed.

This is why it's important to really know your boat. You could roll
up the jib, have the boat sailing fine although slowly, tack, and then
find your self in an awkward situation if you were in tight quarters
and counting on being able to tack again or have the boat steer
itself.

This is a peculiarity of our boat. You mileage will certainly vary.

--

Roger Long