Re: [PSUBS-MAILIST] Need advice, new builder.

["Dale" <heinzind@cadvision.com>]

-----Original Message-----
From: Carsten Standfuß <MerlinSub@t-online.de>
To: personal_submersibles@psubs.org <personal_submersibles@psubs.org>
Date: Wednesday, May 02, 2001 1:08 PM
Subject: Re: [PSUBS-MAILIST] Need advice, new builder.


>Hi Stan,
>
>you wrote your main cylinder is 24 x 75" ( 610 x 1905 mm)
>and your tower cylinder has a diameter of 21" ( 533 mm).
>If you want to sit upright - the tower should be at least 400 mm higher
>at the top than the main cylinder. This indicates a volume
>of 557 Liter plus 89 for the tower and some more for the ouside
>displacements like thruster, engines , lamps, keelweights, manipulator
>etc.
>
>All together about 700-750 Liter equal to a displacement of 0,7 -0,75 t.
>
>There is no rule how much freeboard or reserve bouancy a midget
>sub should have - but a G.E.G - Rule (general estimate golden rule)
>says that the reservebouancy should be between 10 -30 % of the ships
>displacement for subs which want to travel also on the surface
>- especially with open hatch...
>
>Smaller boats and boats which needs more seaworthness should have the
>greater number, bigger boats and lake boats could have more in direction
>to
>the smaller number.
>
>Sgt.Peppers ration is about 500 Liter to 90 Liter =  18 % reserve
>bouancy.
>Sgt.Peppers is pretty stable in all directions with me standing upright
>on the pressure hull short before climbing in.
>
>CSSX ratio is about 57 t to 10 t = 17 % reserve bouancy.
>
>Your figure is : 700 liter to 45 Liter = 6,4 %. Thats is very low.
>If you sit inside and a beautiful girl sitting for pictures on the
>hull - the sub started to dive.. You should maybe double the
>soft tank volume .. Your 16 inch (400 mm)high tower alone has
>about 80-90 liter volume - and will come out of the water just half
>way..
>(The pressure part volume of the sub which comes out of the water is
>equal
>to the volume part of your tanks which stays under the waterline.)
>
>You have 12 x 3,8 = 45 Liter = V = displacement over the waterline
>You tower diameter is 21 inch or 0,533 m = D
>and with H = high of the tower comes out the water
>
>V = ( D x D x 0,785)  x H  or
>H = V / ( D x D x 0,785 )
>  = 0,045 / 0,533 x 0533 x 0,785
>  = 0,2 m or 200 mm or 7,9 inch freeboard.
>
>You freeboard should at least so great that the complete tower
>comes out the water (about 16 inch) - and for a better surface
>stability the main pressure hull in the hole longitudinal direction
> - to create a waterline ..
>
>The aluminium/epoxy combination is exotic - but why not..
>
>Good look with the "Tauchende Ente" ,
>regards Carsten
>
>
>Stan Muller schrieb:
>>
>> Hi All,
>>    I have been visiting your web sites for the past six months, and now
>> I'm trying to apply some of what I have learned. I am building my own
>> dry submersible. (Diving Duck)
>>    I have two aluminum cylinders (tanks) one is 24" by 75" and the other
>> is 21" by 62" The larger is to be the hull and an end of the other is to
>> be the conning tower. When assembled, the 1/8" aluminum will be covered
>> with several layers of hand laid 6 oz. fiberglass epoxied on. There will
>> be five, lexan 1/4" by 6" diameter portholes in the conning tower. two
>> six gallon ballast tanks will be mounted on the exterior of the hull,
>> and will be blown with CO2.
>>    I have built a 6' articulated arm with a grabber that will be mounted
>> on the port side of the hull along side and below the conning tower,
>> where it can be seen from the inside. It is built with pivots at the
>> wrist, elbow and shoulder, and will follow the movements of my arm
>> inside the sub. There will be no through hull mechanical fittings, for
>> the arm, as it operates with hydraulics.
>>    Maximum depth of operation will be twenty feet, being at one
>> atmosphere with a surface air supply through an umbilical from a tender.
>> It will be sealed and pressure tested to thirty feet, before any trials.
>> Emergency air will be onboard, as will drop ballast, and the other
>> safety measures, that are outlined so well on your many web sites, will
>> of course be included.
>>    Now for the questions; Am I on the right track so far? Is there
>> anything that I should be concerned with that I haven't mentioned? Do
>> you think that 12 gallons of air ballast will be enough if everything
>> else is properly engineered?
>>   Any and all assistance will be appreciated.
>> Thanks and best regards, Stan in Missouri.
>


A good one for the FAQ section..


dale.