[PSUBS-MAILIST] Lurker finally surfacing!

Tue Aug 28 23:02:04 EDT 2018

Jim,
don't take my figures as gospel as I was using a basic program & there are other
factors to consider apart from the measurements I worked on.
However those results indicated that if you did some serious calculations you 
could go a lot deeper than you intended.
There are some talented people in the group with regard to hull calculations
& reinforcement etc. ( I'm not one of them) I am sure if you asked for an opinion
on your pressure vessels crush depth you would get some good advice.
Have you had a look at the "Guernsey Submarine" site?
http://www.guernseysubmarine.com
A great resource there, with supplier links.
Anything you aren't sure of just ask. 
Cheers Alan

> On 29/08/2018, at 1:22 PM, james hughes via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Thanks Allen for that hull calculation!  I hope you're right!  I thought it might be shallower than that without reinforcement.  I've tried to build a good safety margin in all the parts on the boat (using thicker steel in the conning tower, for example, than what the K250 plans called for).  Still, this being my first boat I don't really want to go deeper than I could safely get up from on SCUBA (I've got a 2" flood valve if I ever need to get out while on the bottom).  Plus most of the sea life I'm hoping to see is usually in shallow water.  But you're right, little more investment now may make a difference if I decide to go deeper for some reason in the future.  
> THANK YOU again and God bless, Jim
> On Monday, August 27, 2018, 2:51:34 PM PDT, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 
> Hi Jim,
> thanks for the introduction, and welcome along.
> Can't help you with the seals as my motors  are external.
> I have been making my own thrusters & have contacted seal reps &
> even emailed the manufacturer for advice on a non standard mounting
> method I was proposing. Normally seals are used on pumps to keep
> fluid that is under pressure in rather than out as in our case.
> I did a quick calculation on your pressure vessel & it came out as a 600ft
> crush depth. Don't take that as gospel, but it may be worth looking at it
> in depth if you haven't already. If the 600ft is right you could dive to 300ft
> with that hull! For all the work that goes in to building a submarine you may
> find that it is only a relatively small amount of extra effort & cost to give
> you an extra 200 ft of diving capability. I would think about this first before
> choosing a seal as the added pressure may have bearing on your choice.
> All the best,
> Alan (New Zealand)
> 
>> On 27/08/2018, at 4:11 PM, james hughes via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> 
>> Good evening All,
>> 
>> My name is Jim and I’ve been a lurker on this list for many years now.  Long before now I’ve intended on making my presents known to the whole group (I’ve contacted several members off list over the years) but have always seemed too busy to do so… Well, now I’ve pretty much got all the time in the world and am using much of it to finish building my sub…
>> 
>> Here’s a little about me: I’m 56.  Retired navy Chief (I was a corpsman).  Just finished earning a BS in marine biology thanks to the GI bill.  Now I’m finally finishing the behemoth that’s been sitting in my brother’s backyard for nearly 15 years now…
>> 
>> My boat started as a modified K250 (for which I have blueprints) but morphed into something of a money pit since the day I saw and bought a “real bargain” (a giant pressure vessel) at a wrecking yard.  The pressure vessel that I’m using for my hull is 12.5’ long, 5’ in diameter and 5/8” thick.  It would have cost about $15K new, but I got it for $300!  My boat will be named “Pipedream” when it’s done because my original idea called for the hull section being made from a piece of pipe.  I don’t plan on going deeper than 100 feet and will likely stay above 60 feet most of the time.
>> 
>> One of the reasons I’ve finally surfaced on this list is to ask for help.  Does anyone have a working plan / blueprint of a through hull connection for a drive shaft?  Or can someone direct me to one?  I’ve got a 10 horsepower motor for propulsion that I plan on using to turn a 1 inch diameter, 5 foot long shaft with a 12” propeller.  I’ve read all I can find about mechanical seals and watched all the youtube videos on them that I could find…. Can anyone recommend specific mechanical seals and bearings (manufacturer / source or catalog number)?  My nephew in Texas works at a machine shop and assured me that with the equipment he has, that he can make anything I ask for if I can only get him a basic blueprint or plans for a part with the seals and bearings that I need inside.  I need to wrap up the issue with the through hull ASAP as the guy who has done most of my welding is moving next month and I don’t want to get someone new to put that part in (the welder I have is VERY good at what he does).  I would be very grateful if someone could help me with this particular issue.  Thanks in advance for any advice or help!
>> God bless, Jim
>> 
>> 
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