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Vance great to see someone else come up with the same numbers. I
have the same but
I have two battery pods. So now I am at 500lbs. Now also include an
electronic pod and my
motor pod. This brings me over 600. Just seems like to much for a
drop weight.
The two battery pods are linked together with cross over pipes and
the pods are tied to the
other pods. Given the battery pods have thru hulls sealing the
others, so all should not flood
but just calculating for worst case.
Dean
In a message dated 12/3/2009 12:47:27 P.M. Central Standard Time,
vbra676539@aol.com writes:
Dean,
Why would your drop weight be so big? A 12" pod X 120" is roughly 7.85
cubic feet of volume which would displace about 500 pounds. Your internal
volume (figuring schedule 40ish) would be about 6.9 cubic feet. If the battery
pack is 6X8" in cross section and 108" long, that's 3 cubic feet. Subtract
that from the internal volume of the pod and you've got just under 4 cubic
feet of free space or 250# of seawater on a bad day. So, a 250# dropweight
would equalize your trim for a flooded pod and your normal trim and
fairwater system would get you home. Yes? No?
Vance
-----Original
Message----- From: Recon1st@aol.com To:
personal_submersibles@psubs.org Sent: Thu, Dec 3, 2009 12:02 pm Subject:
Re: [PSUBS-MAILIST] Reserve buoyancy
Alan this is in the line of my thoughts. From the beginning, for
my purposes of
exploring Lake Superior, I need to cover large areas. Speed and
endurance are
required. This is the reason for me carrying 18- 85amp batteries
in external battery pods.
If I look at the volume of water in a full flood state the drop
weights to compensate
would be much heavier than I would like.
A 6000 lb lift is only the extreme as this can be my overall
weight. Safety is for sure
not to be compromised, my skinny little butt on the line. I am
just thinking this could
be a solution. I don't feel that the hatch breaking the surface
to allow egress is needed
for an emergency situation when there is a surface support craft.
With a full 6000 lb +
lift capability.
Dean
Hi
Mark,
Re the large ballast tanks, another thought is that the larger they
are
the more drag, & inertia due to them being filled with water
while
submerged. I'm not sure how much of a problem or extra drain on the
batteries this would be. Someone with experience might like to comment
on that.
Alan
----- Original Message -----
From: "F. Marc
de Piolenc" <piolenc@archivale.com>
To:
"Personal Submersibles" <personal_submersibles@psubs.org>
Sent:
Thursday, December 03, 2009 7:00 PM
Subject: [PSUBS-MAILIST] Reserve
buoyancy
> I've been silently following the tender/reserve
buoyancy discussion. As
> my primary interest is in salvage rather
than sightseeing, I have
> assumed from the beginning that any sub
that I build or am involved in
> building will follow safety criteria
more like those of cruising Naval
> submarines than research subs.
But now, reading the report of the
> salvage of the Alvin by the US
Navy, I see that the allowances for
> research subs are
inadequate.
>
> Aluminaut was selected for the salvage op
because she was the most
> autonomous and robust of the submersibles
available. After her first
> dive, when she spent several hours
trying to insert the lifting toggle
> in Alvin's hatch, she surfaced
with her batteries exhausted. It proved
> to be impossible to
recharge her at sea, because the main hatch had to
> be kept open to
allow hydrogen to escape, and when it was left open she
> shipped
water! She had to be towed to sheltered water for repairs and a
>
recharge. This is all the more remarkable because Aluminaut is the most
> seamanlike of all the research submersibles that I've actually
seen.
>
> Battery vented into the crew space? No means of
airing the boat without
> leaving the hatch open? I can understand
not providing a separate
> snorkel or air-induction trunk - this is a
deep diver, and every
> pressure-hull penetration is a potential
failure point - but in that
> case the saddle tanks should have been
made larger and some means of
> fitting a funnel over the main hatch
to prevent water ingress should
> have been provided. And as for
venting the battery into the crew
> compartment, ANY arrangement is
preferable to one that exposes the crew
> to hydrogen, or worse -
chlorine!
>
> http://www.archive.org/details/recoveryofdeepre00unit
>
> I assume that reluctance to add saddle tank volume in a personal
sub is
> due to the need to trailer it home. If it exceeds maximum
highway specs
> it must obtain a special movement permit every time
it hits the road.
>
> Best,
> Marc
>
>
>
>
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