TC,
I think the issue is that most of the people here on the list that will give you some advice have looked at what it costs to build a shallow ops boat and one that has a deeper range and conclude that it doesn’t really cost any more to go to a deeper depth. When they also run the numbers, they find that a sub with the dimensions you propose is outside of the budget of most home-builders. And finally, a larger sub presents launching and handling issues. There are very few large PSUBs, 1 completing construction and 1 undergoing sea trials in Europe along with a very innovative sub being built in Colombia for a US party that uses unusual hull materials that if successful, will open up opportunities for more large PSUBs.
When the membership considers subs similar to the Russian tinniest sub, there are a lot of safety issues that remain difficult to resolve. Safety is paramount and the submarine community (the big boys) is very conservative, as a result they have few large catastrophes, many PSUBbers also hold these values.
Don’t be discouraged, the PSUB group sees a lot of new comers approach the list with ideas of building a larger submersible with some characteristics that are out of the norm. Over time, these new comers if they are serious and stick around, usually end up with a more economical and easier to build smaller sub. Those that don’t clearly define what they want their sub to do early on and perform a lot of research and supporting calculations usually pay for it later upon launching and sea trials where stability and trim issues finally become obvious…there are a lot of sub lawn ornaments and garage queens out there.
R/Jay
Resepectfully,
Jay K. Jeffries
Andros Is., Bahamas
Save the whales, collect the whole set.
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of T.C. Craig
Sent: Saturday, September 19, 2009 1:43 PMSubject: Re: [PSUBS-MAILIST] Hello; Design; Materials; Thanks
Dan,
If by "sarsacm" you mean my last comment to Alan, I can tell you that I wasn't trying to be sarcastic. I was having an honest moment of revelation.
That being said, you might be sensing some frustration with the process.
When I say, " I'd like to build a 25' long submarine with a 6.5' diameter that has a crush depth of 80' " what I'm hoping to hear is, "oh! Why didn't you say so. Traditionally, depths of 80' to 100' require roughly 3/8" steel +/- usually reinforced with x-type stiffeners though you need to run a full calculation.... " Or, "TC, you're running in such shallow water (6' - 30'), 5/16" or less would work reasonably at those depths, as would (gasp!) GRP/composites, but those aren't ABS recommended, of course you'll have to do the full range of analysis, and probably run ambient."
I think a lot of people come to this board expected to get a very informal/rough estimate of the viability of their vision, only to be disappointed by the repetitious suggestion of more research. While research isn't bad, obviously, I think this board is seen as a resource to fill in the holes that other research didn't provide. I know that I've had a huge problem finding design discussions of super shallow depths, that I hoped this board would fill. Few are designing shallow divers, and even fewer are talking about them.
For instance, does anyone remember the "tinniest sub in Russia"? I don't recall his name, but his tiny sub could travel one-hundred kilometers and dive 30'. And he built it during an era of sever soviet oppression. That seems like a design to work with. While I'd certainly change the outside design, it looks like a fun, long distance craft that gives a nice taste of submarine travel.
R,
-T