[PSUBS-MAILIST] G.L. summary Pressure Hulll

[Alan]

Hank,
I assume it is for both, but most often over pressure.
There is an over pressure relief valve & in some boats
you use the same valve & push it open against the
spring force to release the few psi of pressure that
may be left.
Alan

Sent from my iPad

On 12/12/2013, at 3:36 AM, hank pronk <hanker_20032000 at yahoo.ca> wrote:

> Alan,
> Is this equalization from overpressure inside the hull? or external pressure.  
> Hank 
> 
> 
> On Wednesday, December 11, 2013 1:23:21 AM, Alan <alanlindsayjames at yahoo.com> wrote:
> Can anyone enlighten me on what sought of mechanism
> is used that renders the opening of the hatch possible only after
> equalisation, as per G.L. Requirements?
> Thanks
> Alan
> 
> Sent from my iPad
> 
> On 11/12/2013, at 3:01 PM, Alan James <alanlindsayjames at yahoo.com> wrote:
> 
>> Hi,
>> I'm not covering much in this section because if I started on construction
>> regulations, I would just be duplicating what was printed.
>> G.L. wants you to have manufacturer certificates for every non structural screw.
>> Any company you contract to do your welding has to have their facilities, personal
>> & supervision approved by G.L..
>> Some points of interest are.... hatches need to be opened from both sides, they need
>> to be able to be secured open, they need to be designed in a way that opening of the
>> hatch is only possible after equalization. Two measures are required to guarantee that
>> the hatches are closed & secured before diving; one measure is to be visibly noticeable.
>> Mechanical measures for stopping a banging of the hatch is required.
>> Any external through hulls are to be protected against damage by appendages or covers.
>> If you are doing calculations on a computer you have to prove that the program is suitable.
>> Alan
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