David. Very impressive models. There was a "Stingray", working model. of a decent size, on E-bay some while ago and I was sorely tempted, but a) it was a bit big for our pond average depth, and b) I didnt make it !! it is on my list of things to do.
The Seaview was available as an either a Moebius models or Polar lights kit and I believe 38 inches or so long, I saw it in Comet miniatures (who may have also made the Skydiver) and wondered about it at the time…would it r/c ok??
.Ashley