Re: [PSUBS-MAILIST] dome hatch lift force

Subject: Re: [PSUBS-MAILIST] dome hatch lift force

From: Øystein Skarholm <skarholm@gmail.com>

Date: Wed, 4 Nov 2009 17:51:51 +0100

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Reply-to: personal_submersibles@psubs.org

Sender: owner-personal_submersibles@psubs.org

Take also into account that when you (and others) are inside the sub the heat will warm up. This will cause the air to expand and create additional upward pressure.

P1*V1 P2*V2

---------- = ---------- T= temeperature in kelvin. 0 degree celsius = 273,15K

T1 T2

2009/11/4 Alan James <alanjames@xtra.co.nz>

Just calculated the weight of water at the point of total emersion

as being 22.343 kg, so that would leave a maximum lifting force

of the dome against its mounting at 6kg wich isn't much to counter.

Dome- 550mm x 35mm thick x 275mm high.

Regards Alan

----- Original Message -----

From: Alan James

To: personal_submersibles@psubs.org

Sent: Thursday, November 05, 2009 2:52 AM

Subject: Re: [PSUBS-MAILIST] dome hatch lift force

Thanks Oystein & Jens,

I was just getting an idea of the upward force on the acrylic

dome attachment mechanism, wich in my case would be

about 27kg (550mm dome) minus the weight of water on it at the point of submerging. (more calculations).

Regards Alan

----- Original Message -----

From: Øystein Skarholm

To: personal_submersibles@psubs.org

Sent: Wednesday, November 04, 2009 11:37 PM

Subject: Re: [PSUBS-MAILIST] dome hatch lift force

F(N)=int.pressure(Pa)*(Area_int.hatch (m^2) Internal upward force

F(N)=ext.pressure(Pa)*(Area_out.hatch (m^2) = External downward force

In addition the self weight of the hatch will cintribute to downward force.

2009/11/4 Alan James <alanjames@xtra.co.nz>

Hi psubbers,

I'm trying to calculate what the lifting force will be on the

dome in my hatch when it is just submerged; but aren't

quite sure what I have to take into consideration to calculate this. Any thoughts on this?

Thanks, Alan

--
Vennlig hilsen
Øystein Skarholm