Joe,
It appears to me that if you are
considering an ambient design that also has large ballast capacity, you are
going to have to carry a ton of on board compressed air. That seems to be
the issue with ambient designs.
Myles.
----- Original Message -----
Sent: Sunday, October 30, 2005 11:50
AM
Subject: [PSUBS-MAILIST] Re: Preliminary
calculations, please check me
Myles,
I am sitting here trying to make sense of some numbers but you
may be interested in this as you are interested in the same basic dimensions I
am.
According to the NAVPERS manual a Gato class fleet boat had a surface
displacement of 1,750 tons and submerged 2,228 tons at neutral trim. The
MBT were 16% of trim at 359 tons, not counting fuel tanks which were
always full of either D.O. or seawater. There is a difference of some 28%
between surface displacement and neutral.
I do not yet know how this scales down but I am trying to figure out
some basics here, like tank size and air requirements. I see widely varying
numbers in different submersibles.
If I have to double the cabin air to maintain a dry ambient boat @ 33', I
may have to rethink an open bottom design.
I am finding lots of stability considerations as well.
Joe
From: Myles Hall <myles.h@sasktel.net> Reply-To:
personal_submersibles@psubs.org To:
personal_submersibles@psubs.org Subject: Re: [PSUBS-MAILIST]
Re: Preliminary calculations, please check me Date: Sun, 30 Oct
2005 11:11:19 -0600
Joe,
I'm sure it's all dependant on
what you want the sub to do. For me, I want something with decent
surface running so that I can drive the thing to the dive location.
With this in mind, I am looking for quite a bit of ballast bouyancy to get
as much of the boat out of the water as I can to reduce the drag. I am
looking to have my dive planes up high on the hull so that they clear the
water as well when in surface trim.
However, I figure if you just want
enough ballast to get you sufficient free board, you could get away with
considerably less than 40%.
Myles.
----- Original Message -----
Sent: Sunday, October 30, 2005 6:38
AM
Subject: [PSUBS-MAILIST] Re:
Preliminary calculations, please check me
Thanks Paul and Myles,
30 to 45% is quite a bit, I am still working the numbers to see if this
is doable.
Joe
From: Paul Kreemer <paulkreemer@gmail.com> Reply-To: personal_submersibles@psubs.org To: personal_submersibles@psubs.org Subject: Re:
[PSUBS-MAILIST] Preliminary calculations, please check
me Date: Sat, 29 Oct 2005 18:50:07 -0700
Yes, using 63 lb/cf of seawater gives about 16cf needed
to weigh 1000lb.
I think a WWII style boat which was more on the surface than
submerged
would have 30% or more reserve buoyancy. Like Myles
says.
Joe,
My design calls for about
45%. I want to get that thing out of the water when surface
running. Also, I
figure a guy needs all the bouyancy he can get when launching
the thing so that
you don't need 6' of water. I'm going for the "better
to have too much
than not enough" concept. Hopefully I'm not overlooking
something.
Myles.
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