[PSUBS-MAILIST] FW: Casper 2

Tue Jul 31 08:40:39 EDT 2018

Graham,
firstly I am assuming you meant diameter not radius with regard
to the new pod.
I did the calculations for fresh water & with carbon steel.
Old end caps in air 24lb in water 20.9lb x 2
Old cylinder in air 429lb in water 190.32.
So 190.32 + 41.8 = 232.12 heavy for the old pod in water.
Am ignoring the battery weight as you say they are the same in both pods.
New end caps in air 21.8lb in water 19lb x 2
New cylinder in air 229lb in water -189.71lb
So -189.71lb + 38lb = -151.71lb buoyant for the new pod in water.
You need 151.71 + 232.12 = 383.83lb ( difference of weight in water between old
& new pod) extra lead to get you to the neutrally buoyant state.
Hope that's right. See if anybody else comes up with anything different.
Cheers Alan

Sent from my iPad

> On 31/07/2018, at 11:31 PM, graham bayliss via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Hi Alan
>  
> The original pods are as per plan 57 -3/4" twelve inc sched pipe I have built mine six feet long and fourteen inches radius out of 1/4" steel plate my end caps are flat plate 1/2" thick  I carry three leisure batteries 18 kgs each plus I have added 150 lbs of lead to the out side of the cases .I made them longer to carry extra batteries for extra power.
>  
> Graham
> From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Alan via Personal_Submersibles
> Sent: 31 July 2018 12:08
> To: Personal Submersibles General Discussion
> Subject: Re: [PSUBS-MAILIST] FW: Casper 2
>  
> Graham,
> to do this accurately we would also need the dimensions of the
> previous pod & it's battery weight to see what positive or negative
> effect it was having. Ie. if it was 20lb negative then that is our
> target with the new pod to get your sub back to neutral buoyancy.
> Alan
> 
> Sent from my iPad
> 
> On 31/07/2018, at 10:14 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Graham,
> what is the wall thickness of the battery pods. Is the 14" the outside
> diameter. Is the length you quoted to the ends of the end caps?
> Are there reinforcing rings in the pods. If so what dimensions.
> Also what is the weight of the batteries. You should be able to get
> that spec off the internet.
> I have the program " Under Pressure" that gives weights & buoyancy.
> I would have to put hemispherical end caps in the equation as thats
> it's limit.
> You might get a better offer from someone with a better program but
> I am sure I could get you in the ball park.
> Cheers Alan
> 
> 
> Sent from my iPad
> 
> On 31/07/2018, at 9:48 PM, graham bayliss via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
>  
>  
>  
>  
>  
>  
> Hi
>  
> my name is Graham Bayliss I  have been building Casper 2 for many years and now find my self frustrated by science I have craned my sub into the water three time only to be frustrated by buoyancy problems I have redesigned my battery tubes to carry more batteries. this has meant they are very buoyant and being on the bottom my boat they tend to want to turn her on her side. My housings measure six feet long by fourteen inches I can not calculate how much weight I need to make these negative buoyancy I have three leisure batteries in each housing plus one hundred and fifty pound of lead on top. this does not counteract the upforce which each housing is subjecting my sub to. I am lost as to how I can over come my problem  as  she is determined to roll . can some one help me please.
>  
> regards
>  
> Graham
>  
> Pictures  of Casper 2 being built are on the site if you need to look at what I have built.
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