Re: [PSUBS-MAILIST] glassed-in ballast tanks

["Dan H." <jmachine@adelphia.net>]

Alec,
I think I follow what your describing.   Try it and see if your satisfied.
Your testing will prove it, one way or the other.  I can't imagine the sub
turning totally nose up or nose down just because of the weight placement in
the overall design.    Now that we discussed this, I think I'm going to try
some of the same one ballast tank tests sometime when I have help around to
see how my sub reacts.  With the battery pods so low on the K-350, it
shouldn't get to vertical.

In my first sub trials I got carried away with flipping valves and got
Persistence rocking quite a bit.  It was enough that I became concerned,
what would happen if my 400 pounds of removable lead weights slid forward
across the deck and ended up in a pile against the end of the hull.  I
thought I would become a bobber for sure.

I didn't know you had both of your air tanks plumbed in all the time.  I
don't think the Captain designed it that way.  Most likely Dale decided on
that.  I only have one tank connection but carry two tanks.  I run off one
tank, and if I run low in that one, I switch the regulator over to the
other.  I get several dives out of each tank but have decided to never take
more then one dive out of the second tank until I replace the first.  I use
it like a reserve tank until I get the replacement full tank on board.

I'll be in Fla. in early June and in Europe while your in Fla.  We'll
definitely get together in Maryland someday though.
Keep me posted with your testing.

Good luck, Dan H.

----- Original Message ----- 
From: "Alec Smyth" <Alec.Smyth@compuware.com>
To: <personal_submersibles@psubs.org>
Sent: Wednesday, April 27, 2005 10:42 PM
Subject: [PSUBS-MAILIST] glassed-in ballast tanks


> Hi Dan,
>
> I remember you making that comment some months back about the bleed holes,
and it made me think about this issue. Snoopy carries two SCUBA tanks for
blowing ballast. Since one of the tanks also blows the VBT, it tank empties
considerably before the other. I presume the most likely cause for doing a
buoy impersonation would be if you blew ballast and one of the SCUBA tanks
was empty while the other was full. Lets say for sake of argument you
successfully blew the forward tank and the rear one remained flooded, thus
putting the sub severely nose up. If you found yourself in that predicament,
what one would do is switch tanks, to blow aft ballast with the remaining
air. I presume the issue is that depending on the location and depth of the
aft tank lower opening, you could find that air injected into the aft tank
would escape through the bottom of the tank rather than rise inside it. That
would prevent the stern from rising. Plan B would be to lower the bow, but
you couldn't do that either because the vent is at the rear of the forward
tank. Thus the buoy attitude would become permanent. If I had the small vent
holes in the forward tank, it would slowly flood, and I could switch tanks
in the meantime, waiting until the angle was a little less radical before
blowing aft ballast. I presume this is the reasoning behind the Captain's
comment, and I can't see any gaps in it.
>
> However, perhaps Kittredge was not thinking of stovepipes that protrude
downwards from the tanks. If the stovepipe were located such that I can blow
tanks even with an extreme angle on the boat, then I would rather like to
switch tanks without losing any of my scarce air. For this reason, when
Snoopy is back together I'm planning to conduct a simulation before drilling
those little holes. The test is to blow one ballast tank only, and see if at
the greatest angle possible I can or cannot still blow the second tank. This
obviously would be done with someone standing by to assist. If the
stovepipes do the trick, I think I'll keep the tanks un-drilled.
>
> I really appreciate your having made that comment, because it was a
scenario that had not occurred to me, and led me to think about the
placement and depth of the stovepipes. D'you think my reasoning is sound?
>
> I'm planning on being in FL from July 18th to 28th. Let me know if you'd
like to convoy down with two subs, that would be terrific.
>
>
> thanks,
>
> Alec
> -----Original Message----- 
> From: Dan H. [mailto:jmachine@adelphia.net]
> Sent: Wed 4/27/2005 5:48 PM
> To: personal_submersibles@psubs.org
> Cc:
> Subject: Re: [PSUBS-MAILIST] towing requirements
>
>
> Alec,
>
> If it helps, my 350 has a 3 Hp aft thruster and two 3/4 Hp side thrusters
and it moves along.  Exactly how fast is just a guess but I'd say about five
MPH.  Total 4 1/2 Hp.   As you probably know 9 Hp won't move you twice as
fast.
>
> A note on glassing in the under side of the soft tanks,  I was talking to
Captain Kittredge when I was doing mine and her mentioned to be sure to
drill a few holes in the most forward and aft ends of the tanks to insure
any trapped air would bleed out if you ended up nose of tail straight up
like a buoy.  I drilled two 5/8 holed in each end of mine.  They don't burp
out at the ends anyway.
>
> Where in Fla. are you going and when?  I'll be near Fort Myers in a few
weeks but I won't have the opportunity to take Persistence.  :-(
>
> Dan H.
> ----- Original Message ----- 
> From: Alec Smyth <mailto:Alec.Smyth@compuware.com>
> To: PSUBS <mailto:personal_submersibles@psubs.org>
> Sent: Wednesday, April 27, 2005 11:12 AM
> Subject: [PSUBS-MAILIST] towing requirements
>
> Hi all,
>
> I’m planning a trip to South FL, and have run into the issue of finding a
tow boat for a K-250, since I would need to do tows of 4 to 7 miles each way
in open water. One option is to purchase an inflatable, and they come in a
huge range of sizes and engine capacities. Smaller is better for me, but
only so long as it’s not TOO small. Any little tender with a whimpy motor
will move a K boat to some extent, but for those who have “been there done
that”, what do you consider would be appropriate for open water use, for
example getting home against the Gulf Stream? If I can decide on 35 HP, 50
HP, etc. I can work that back to a matching boat.
>
> The sub itself, BTW, I have modified for towing by glassing in the ballast
tanks and using stove-pipes, so that they don’t “burp” as much.
>
>
>
> Thanks,
>
> Alec
>





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