[PSUBS-MAILIST] Dry Ambient Sub

Sat Feb 17 17:27:43 EST 2018

 Hi Terek, i completely agree with Alan, as tge limits of the human body
will soon be discovered if there are design flaws and you can't escape.  I
soon found this to be true with my first full scale model of the
SeaQuestor. Cardboard and blue tape are cheap and well worth the time.

On Feb 17, 2018 10:42 AM, "Alan via Personal_Submersibles" <
personal_submersibles at psubs.org> wrote:

> Hi Tarek,
> no diagrams came out in my email.
> I would do a full size model of what you intend & get in &
> make sure the space works. Especially if you intend to have a
> diver exit in the bottom. Can you get out comfortably with scuba
> tanks! Also as you go out the diver exit the sub becomes lighter
> to the extent of the weight of yourself & your dive gear.
> Tim's ambient sports sub has a system for adjusting this loss of
> weight by letting in more water. I am not sure how this works but
> if you adopted it you would need to allow for a volume of water to
> come in to the bottom hatchway of the sub. And of course the oposite
> is true when you re-enter.
> If you have problems with stability when diving you could always add
> syntactic foam up high & more lead down low to counteract it.
> Have you had a look at Cliff's R300 on the projects page, as the hull
> seems a similar size.
> Cheers Alan
>
>
> Sent from my iPad
>
> On 17/02/2018, at 11:41 PM, Tarek Harb via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Dear guys,
>
> I would like to share with you my initial plan for the Dry Ambient sub I
> am building.  I would love to hear any suggestions or comments about my
> calculations.
>
>
>
> The Dimensions of the Dry Cock pit is: width = 0.7 m, Length = 1.6 m, and
> Height = 0.85 m.
>
> This will give a total volume of: 0.952 m3.  The Cock pit will produce an
> upward Buoyant force of about 950 kg (I do understand that kg is not a unit
> of force, but I do this for sake of clarity).
>
>
>
> The total Mass of the Sub is around 850 Kg.  So in order to make sure that
> the sub dive, its weight (or mass) has to be heavier than the Buoyant force
> produced by the
>
> Cock pit, so I will add about 100 kg of Lead to compensate.
>
>
>
> I did the calculations of the Center of Gravity and the Center of
> Buoyancy, from which I obtained the MetaCentric height.
>
> this calculations indicated that the design will keep the sub at a stable
> condition on surface and while descending, which is very important and
> critical.
>
> I can provide this calculations later on if anyone interested.
>
>
>
> Here is a rough diagram indicating the thoughts so far
>
>
>
> *On surface*
>
>
>
> <image005.png>
> <image006.png>
>
>
>
>
>
>
>
> <image011.png><image012.png><image018.png>
>
>       FB                           FB                          Water level
>
> <image021.png>
> <image024.png>
> <image025.png>
>
>
>
>
>
>
>
>
>
>
>                         Weight of all sub = 950 Kg
>
>
>
> 1= Cock Pit. Volume is 0.95 m3.
>
> 2= Main Ballast Tanks.  Volume is 0.95 m3, this will give an upward force
> of 950 kg assuming that the density of water is 1000 Kg/m3.
>
> 3. Trim Ballast Tanks
>
> FB= Buoyant force = both forces will add up to cancel the weight of the
> sub.
>
> At this stage all the Ballast tanks are empty and full of air.
>
> <image026.png>*Descending*
>
>                              FB = Buoy Force from Cock Pit
>
>
> <image027.png>
> <image028.png>
>
>
>
> <image021.png><image030.png><image032.png><image034.png>
>                                                                 Water
> level
>
>
>
>
>
> <image018.png>
>
>
>
> <image037.png>
> <image038.png>
>
>
>
>
>
>
>
>
>
>
>                        Weight = 950 Kg
>
>
>
> At this stage, the Buoyant Force from the Pit + the Buoyant force from the
> Trim Tanks will equate the downward weight of the sub.
>
> The Main Ballast Tanks are full as the blue color indicates.  Since they
> are full, they will not contribute to give upward force.
>
>
>
>
>
> <image039.png>*UnderWater*
>
> FB = Buoy Force from Cock Pit
>
>
>
> <image040.png>                                                Water
> level
>
>
>
> <image042.png><image044.png><image046.png>
>
>
>
>
>
>
> <image018.png>
>
>
>
> <image037.png>
> <image038.png>
>
>
>
>
>
>
>
>
>
>
>                        Weight = 950 Kg
>
>
>
> Underwater, the Buoyant Force from the pit will equate the downward weight
> of the sub, and it will maneuver using the Motors.
>
>
>
> At a final note, the cockpit will have an exit hole at the bottom.
>
>
>
> regards
>
>
>
>
>
>
>
>
>
>
>
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>
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