Addforce with a min starting speed?

Hello is there a way to addforce right away with a min speed, i need the ship to move right away with no speed up how would i do this? it must be addforce.

Read the manual. Use this:

rigidbody.AddForce(someVector, ForceMode.Impulse);

This will create an instantaneous impulse. Make sure you only do this on one frame- otherwise it will cause rapid (but still smooth) acceleration.