[PSUBS-MAILIST] drop weight

[Alan James via Personal_Submersibles]

Hank,GL says in Section 7 Arrangement for Diving/Ballasting, Control/Compensating & Trimming....In the event of the failure of the compensating tank system, the submersible shall be capableof surfacing by jettisoning of ballast & or emergency blowing of the diving tanks, & has to floaton the surface in an upright stable position.Section 15 Rescue system, 3.1 .... Mathematical proof is to be furnished that, after release ofthe solid ballast the submersible rises safely to the surface & floats there in a stable position.   They stipulate elsewhere that you have to have a drop weight; but from section7 it seems that it is there only to cover a failure of the compensating tank. I assume the compensatingtank is a hard tank. So you would need enough ballast in your drop weight to cover the full condition of your compensating tank. This seems a bit funny because your air for blowing yourtanks has to be enough to cover the event of any major failure of a cavity such as the batterypod. You would think that this air might also suffice for the compensating tank failure.  So as long as you have enough to cover that, & don't turn upside down on the surface or way up,ie. your centre of buoyancy is still above your center of gravity, you should be right.   According to section 7 it seems that as long as there is enough compressed air to compensate for any of thesefailures at your dive depth, then you would need very little weight. I say very little becauseof the rule that you need a drop weight. :)Let me know if it is not making sense.Alan 

      From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Sunday, November 13, 2016 2:45 PM
 Subject: [PSUBS-MAILIST] drop weight
   
Can someone tell me what the proper weight of a drop weight is.  There must be a rule.Hank
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