Rigidbodies without collision

I have a player controlled ship (2D), which I want to be moved with the AddRelativeForce call, so I made it a rigidbody. This seems to have had the effect of making it able to collide with things... which I don't really want to happen (projectiles will be what collide).

Is there a way to take advantage of the force functions and not collide with anything? If not, should I be approaching this a different way?

You could take the collider off.

Or you could use Layers to make sure that the ship only collides with bullets.