;; you should be in age-of-sail.core>

(def my-ship (ref {:position [0. 0.]
                   :name "Virginia Woolfe"
                   :heading (normalize [1.0 1.0])
                   :slots [{:type :downwind-sail :length 2 :furl 1.0}]
                   :velocity [1. 0.]}))

(reset! ships [my-ship])

(start-program)
@my-ship
(stop-program)

(show-ui)
@tracked-ship