Brent,
High speed submarines have a defined speed/depth operating
envelope that they operate within. Outside leads to a rapid depth excursion
and potentially exceeding test depth and/or crush depth. All subs fear
jammed dive planes especially during high speed maneuvers which would force the
sub outside of the safe envelope. In the case of the Albacore, the
drogue deployed from the edge of the fairwater (pulling from the aft upper end
of the sail) caused a torque to be exerted on the hull, pulling it up out of a
dive. The flaps just killed forward speed and thus assisting in keeping
the sub operating within the safe speed/depth envelope. Many things were
tried on the Albacore as this was all new operating ground since no
other submarine had been able to operate at these speeds before. Most of
the concepts tested on the Albacore never made it out into the fleet as
they were not practical or were found not to be needed.
Fleet subs purposely operate a good distant off of the bottom to
avoid unintentional collisions and unfortunately those few times that they have
met with an uncharted sea mount or guyot have been tragic for the crew and
resulted and damage that cannot be economically repaired…the sub usually
has to be decommissioned.
In the case of typical PSUB-sized submersibles, high speed
(greater than 3 knots) will have difficulty stopping or rising sharply in time
to avoid obstacles in semi-murky water (visibility ~20 ft.). This is
evident from experience gained working with human-powered submersible races.
While these subs do not weigh all that much, they entrain a weight of water
that is less than or comparable to that found in a PSUB. They go faster now,
but my experience trying to stop and/or divert our record breaking sub doing
3.94 kts. at the end of the lengthy tank run was very difficult. This was
with the crew stopping the prop and putting the fore & aft planes in a “hard
rise” position. When a submersible did get away from the “catchers”,
they were often damaged by the wall or the tank end. The “catchers”
were lucky that no broken bones occurred as getting hit by a sub was very
painful and left you black and blue for days.
R/Jay
Respectfully,
Jay K. Jeffries
Andros Is., Bahamas
Talk sense to a fool and he calls you foolish.
- Euripides (484 BC - 406 BC)
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent
Hartwig
Sent: Monday, August 25, 2008 8:41 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Stopping Flaps
Dean,
I found a couple more items. I'm having trouble finding a picture of the flaps
open. I had one a while back.
http://imageevent.com/albacore/albacorehistoricphotos;jsessionid=r9qabaad11.tiger_s?n=25&z=2&w=0&x=0&c=4&m=24&p=24
"The parachutes were attached to the after end of Albacore's fairwater
and successfully streamed while the ship was cruising submerged. The resulting
deceleration curves indicated that such a system effectively aided in
emergency recovery."
Project "Bailout" might not have been the most successful of Albacore's
tests but it certainly showed some creativity was at work."
http://www.hazegray.org/navhist/albacore.htm
From: brenthartwig@hotmail.com
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] Stopping Flaps
Date: Mon, 25 Aug 2008 17:03:24 -0700
Dean,
You could install some sort of stopping flaps (speed brakes) on both sides of
your sub that are curved to fit the shape of your hull. Much like a US Navy
test sub USS Albacore. Then operate them with hydraulics or adapted electric
actuators starting with a unit like the Lenco Trim Tab actuators.
I've been planning on having this type or braking system on my winged
underwater gliding subs. With two stopping flaps on the training edge of the
wings. One opening up, and one down at the same time.
"Built as a test bed for the U.S. Navy, the Albacore featured a
tear-drop shaped hull, new diving controls, a dorsal rudder and a new
high-yield steel for her pressure hull. In addition, the Navy, at one time
or another, experimented with speed brakes, contra-rotating screws, a
drag chute, camouflage paint and three different arrangements of stern
control surfaces.
The NSF report ignited debate within Navy circles over a variety of
issues such as the merits of twin propellers vs. singles, and the sacrifice
of surface stability for undersea speed. The result of the
recommendations
and ensuing debate was the U.S.S. Albacore.
The Dorsal rudder was reinstalled and enlarged and the boat
was outfitted with speed brakes. These brakes - another concept borrowed
from aviation - technology, consisted of 10 hinged panels ringing the
after part of the ship. When needed, they were hydraulically opened into
the waterflow, bringing the boat to a rapid stop."
http://www.hazegray.org/navhist/albacore.htm
http://en.wikipedia.org/wiki/USS_Albacore_(AGSS-569)
From:
Recon1st@aol.com
Date: Mon, 25 Aug 2008 18:55:44 -0400
Subject: Re: [PSUBS-MAILIST] Air Tanks
To: personal_submersibles@psubs.org
Frank I am using 12hp for my main propulsion. I gave up trying to
calculate speed but I should have
plenty. The reason for so much maneuverability is the bottom of
Lake Superior many granite boulders
etc. I will need to travel pretty fast to cover any amount of the
Lake. I am thinking of a 20 to 30' above the
bottom but at 6 knots or so when one of those big beast jumps up
in front of me, I am going to need
options. A transfer pump or sliding weight for sure would not fit
my needs. I may even have an
emergency sea anchor deployment for quick stops. Reverting back to
my drag racing days.
I loved the dry dive video. I learned much watching it maneuver I
have greater confidence that my
efforts should yield the kind of performance I am looking for. Not
to mention it oughta be a real
In a message dated 8/24/2008 8:15:39 P.M. Central Daylight Time,
ShellyDalg@aol.com writes:
Hi Dean. I think you're chasing the right idea with front
and back dive planes. I had considered that but let it go because of the
extra work. It just seems to me that back dive planes would be a real plus if
you have enough power to make them work. Did you see the "dry dive"
videos? With the center mounted dive planes the sub stays level when
ascending/diving but it would be nice to be able to angle the sub just with the
dive planes. Like you say, much like flying. I don't know how much speed you'd
have to get to make the dive planes overcome the front/back balance, but if
it's close enough to neutral, it may not take that much power.
Twin trim tanks front and back with a transfer pump would help if
the pump was able to shift weight fast enough. Maybe a sliding drop weight
would be less trouble to make. I will be able to shift the seat forward
and backward a little and I'm hoping that will give me a little angle change.
Damn, I wanna get this thing wet soon! Frank D.
It's only a deal if it's where you want to go. Find your
travel deal here.
It's only a deal if it's where you want to go. Find your
travel deal here.