Whenever I shared beaver torpedos, I was sharing an idea, not a product. I learn as I go along, and I encourage others to share their experiences as they make and use different designs of it. There are numerous ways to build Torps that work well, but what you can do with them depends on how you built them. I planned on sharing more tonight, but family obligations prevented me from doing it. A thorough explanation will have to wait until another day, but I will get you started tonight.
When I built torps to share, I built two basic designs. The first was just 2" PVC with 1/2" rebar the length of the PVC, filled with spray foam, and then the caps were attached. I would either use a screw eye or an eye bolt on the rear cap. The snare would be anchored separately. My second design, and the one that I have used more often has a 3/8"x15" eye bolt that goes through the entire Torp, with a 12/0 swivel and a stop nut on the end. I liked this one, because it was an all-in-one. I have never had problems using this design, because I designed it and understood it, so troubleshooting was never a problem. However, because it only had the eye bolt for the ballast weight, it was more sensitive than the larger version with the rebar. Showing what I mean and how to fix it is easy. Explaining it to someone experiencing problems isn't.
The design that people have mentioned to me that I would recommend trying is to attach an eye bolt to the PVC pipe 1.5" from each end. This would be for people that want to attach the snare to the Torp without having the 15" eyebolt or a long piece of all-thread. The front one for your snare, the rear one for your anchor. I do believe this would work well, although I have not tried it personally, so I can not say with certainty. If you want to try something new and must have an all in one, I suggest trying this.
If you want to build something that you know will work and you can anchor your snare, build this: 2" PVC 20" long, put a 19-20" piece of 1/2" rebar in it, put a cap. Fill with foam, add the rear cap. Set it in the yard for a day. This will allow the foam to set with the rebar on the bottom. Float it in your bathtub, mark the dorsal side, twist your 14 gauge wire to hang your snare off of the front, and somehow secure your snare and torp. There are lots of ways to do this. Stake, cable, earth anchor, etc.
I'll post more when I can...
Have a good one,