[PSUBS-MAILIST] G.L. Summary Stability & Buoyancy

[hank pronk]

Vance,
Funny you mention the inner tube.  I did just that as an experiment on my red sphere sub.  I even painted the inner tube white so it would blend in better.  
I took a big leap of faith this morning, I just finished machining the prop shaft bushing housing.  The housing has a bearing and seals now.  I drilled in two ports (1/8 pipe) to fill and drain the oil.  I like it much better and I have to drain the oil regularly in the second shaft housing anyways.  
I also decided to buy a new motor instead of using the original.  I am driving to the USA tomorrow to pick it up.  That was my Christmas present. :-)    I am very easy to shop for :-)
Hank 



On Thursday, December 5, 2013 10:47:14 AM, "vbra676539 at aol.com" <vbra676539 at aol.com> wrote:
  
Which suggests a big inner tube if you want to convert a DW2000 to that definition. Otherwise, keep the door shut, or prepare to swim. 
Vance



-----Original Message-----
From: Phil Nuytten <phil at philnuytten.com>
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Sent: Thu, Dec 5, 2013 11:11 am
Subject: Re: [PSUBS-MAILIST] G.L. Summary Stability & Buoyancy


The minimum hatch to waterline measure applies to those submersibles 
‘intended to be entered while afloat’ -  
Phil 

From: Jon Wallace  
Sent: Thursday, December 05, 2013 7:33 AM 
To: Personal Submersibles General 
Discussion  
Subject: Re: [PSUBS-MAILIST] G.L. Summary Stability & 
Buoyancy   
 
I think the first sentence is key, "Submersibles 
will be assigned Class only after it has been demonstrated that their buoyancy 
and their static and dynamic stability in in tact condition is adequate FOR THE 
SERVICE INTENDED".  Some of the lack of specificity is because they can't 
conceive of every possible application.  They do however have quite a few 
specifics as you outlined.  Some of the testing won't apply (ie fuel load) 
and it's possible that a narrow scope of service might lower number of tests 
required.


On 12/5/2013 4:08 AM, Alan James wrote:
 

>
>I'm afraid there is  nothing simple in this section. It is lacking in a lot of specifics. 
>There are statements  such as "shall generally meet the standard defined 
>in the following  unless special operational restrictions reflected in the class 
>notification allow a  lower level. & ...Depending on the type of submersible & the  
>operation area, the  distance between the waterline in fully surfaced condition 
>and the upper edge of  entrance openings, air pipes,etc. which may be open 
>for surfaced  operation, has to be approved by G.L. 
>   ABS has  a minimum distance from the waterline to the hatch opening of 30" 
>whereas G.L. states; For surfaced; a  minimum distance between  metacentric height & center of gravity of 10cm. (4") And for submerged, a  minimum distance between center of buoyancy & center of gravity of 5cm (2")  (same as ABS). At no stage will G be above B. (including after dropping the  drop weight) 
>In  the initial paper work sent before construction, a detailed analyses of  stability is to 
>be included.  This  takes the form of analyzing the heeling levers of 10 different load cases in  fresh & salt water, 6 on the surface & 4  submerged & at 6 different heeling 
>angles. So looks like  120 calculations. Heeling forces from  free liquid surfaces, turning circles, wind, ice loads, transference of  equipment & personal & payloads from working devices have to be  considered. 
>There needs to be  sufficient ballast to keep a minimum of 10% of the pressure 
>hull out of the water.  The draught line has to be marked on the hull.  
>When one major ballast  tank is damaged the hatch has to be able to open without 
>water coming in &  the heeling angle shouldn't exceed 22,5 degrees. 
>There is an operational  in water test at the end of construction with evaluation 
>of the center of  gravity upon which the pre build calculations were based. 
>Alan 
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>_______________________________________________
Personal_Submersibles mailing list Personal_Submersibles at psubs.org http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles 
 

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