The Gato-class fleet boat USS Cod (SS-224), which completed seven war patrols in WWII and was decommissioned in 1954 only to survive for another 15 years as an NRF training sub in Cleaveland, has been a museum ship there since 1976. Recently, the museum staff has managed to open her long-ago sealed forward torpedo tubes and a pair of outer doors in preparation for maintenance work.
It provides an interesting perspective shot, complete with an inert MK18:
They also found a series of wood crates and metal boxes stuffed inside the tubes that they think are parts and equipment that were stored there to reactivate and upgrade the tubes if Cod was returned to service.
A commenter who was around when the USS Batfish (SS-310) museum did a similar “untubing” in 2009 said the find wasn’t surprising as they discovered “a tube maintenance sled, block and tackle, and all the attachments for loading and unloading torpedoes into the tubes, as well as probably a half dozen miscellaneous torpedo room parts.”