When this came up a few months I was confused, thinking they only could cloak mines during ENT. It was pointed out that the ship also cloaked and when I watched the episode again I saw it for myself. For quite a while I could not figure out why I thought only mines could cloak. Last night I started reading "The Good That Men Do" again. First time I bailed out 1/3 of the way through. There is was, a passage about Romulans working on cloaking technology and only being able to cloak small devices but not large ships. The writers of the book tried to explain it away saying the prototype ship that could cloak was destroyed and the advancement in technology lost. I don't buy that either.