diff --git a/src/Ur/Run.elm b/src/Ur/Run.elm
index 4802e86..fe67d11 100644
--- a/src/Ur/Run.elm
+++ b/src/Ur/Run.elm
@@ -312,8 +312,10 @@ update inp msg model =
 
         NeedsActivation ->
             let
+                -- Any PUT creates the channel. An ack of nothing does so
+                -- without poking ~zod (`ship = ""`) over the network.
                 ( eventId, reqs ) =
-                    [ Poke { ship = "", agent = "hood", mark = "helm-hi", noun = C.cord "Opening airlock!" } ]
+                    [ Ack 0 ]
                         |> tag model.eventId
             in
             ( { model | eventId = eventId }