Hi,
Dan Hryhorcoff had problems sending this to the alias
and asked me to forward it on. Enjoy!
Regards,
Ray
===================================
Deep Water Testing of Persistence
I've been diving Persistence, my K-350 sub, for a year
now working out some of the kinks and just having fun
with it in relatively shallow water. According to
common practice I need to submerge Persistence to a
depth of 550 feet for about an hour to consider it
safe for manned operation at a depth of 350 feet.
This past weekend Persistence passed it's test.
A month ago Al Secor and I had attempted to do the
test, but it was abandoned because of trouble we had
with the surface boat. It was decided that we would
make another attempt on September tenth.
On the morning of the tenth of this month, my wife
Kathy and I met Al and his girlfriend Christine at
Watkins Glen, a small town at the southern end of
Seneca Lake. My cousin Ted came along to photograph
the event. Seneca Lake is the deepest of the Finger
Lakes located in eastern New York State. It's about
two miles wide by about 35 miles long and was chosen
for the test because of its 633 feet depth.
After transferring the appropriate gear to each craft,
we launched the sub first then Al's middle size boat.
He has three to choose from. This one was on its
trailer and readied for the task. It's a 24 foot
inboard outboard with way more power then we needed
but we were happy to have the extra freeboard it
provided.
We launched and each piloted our crafts out of the
harbor a few hundred yards, then rigged for towing the
sub. Al threaded a heavy short line through a pulley
and attached it outboard on the transom, running from
port to starboard. From the pulley he ran a towline
back to Persistence. When we started towing, the boat
could steer a relatively straight course even with the
sub wandering from side to side following behind, like
a duckling following its mother. The advantage of
rigging in this manner was evident, watching the
pulley run port and starboard along its line as the
sub wondered.
According to the chart of the lake, we needed to
travel north from the marina four miles to reach a
spot where the water was 550 feet deep. We were
fighting a breeze from the north and the lake was a
bit choppy. Towing the sub was like dragging a rock
through the water. If we sped up, the sub would dip
bow down and offer more drag. We had an early start
so we toed slowly.
About an hour later we arrived at the spot, according
to our GPS. The fish finder blinked around from 520
to 560 feet, so we knew we were in the area.
Now it was time. We were really preparing for this
test. I've thought about it for the last four years.
Many times through building Persistence, the thoughts
of gambling the entire project on a line at that depth
made me redo things to get them as perfect as I could.
I still wanted to have a sub when it was over. If
Persistence sprung a leak at 550 feet, it would weigh
about two tons and I would never be able to retrieve
it from the bottom.
By now the wind had picked up some more. We were
seeing white caps but we were on location and it was
time. We planned to first send down a weight on the
line to prove the bottom depth. It seemed simple in
the planning stages but we quickly found the wind
blowing the boat southward and our weighted drop line,
acting like a sea anchor trailing at about forty-five
degrees downward and aft. With fifty feet of line
out, we gave up and reeled it back in. The fish
finders said it's the place and the GPS said it's the
place so it must be the place.
With that in mind, we started rigging the sub for its
trip down. Christine, read off the checklist I made
up, and my wife Kathy manned the spool of half-inch
poly line we were hanging the sub on. I jumped over
to the sub and did the doing as Al handed me the
components and tools to complete each step. It sounds
simple but by now we had all we could do to reach
across between boats and also keep them from banging
together. The water was getting even rougher. I tied
on the retrieving line with more knots then necessary
and then climbed in the sub and shut all the power
down, closed off the air, put external plugs on the
MBT vents, opened the MBT valves in the sub and put
the equivalent of my weight in the sub which had an
empty VBT. Next I climbed out, closed the hatch and
installed a clamping device to hold it closed tightly.
After that, I attached two weight pails to the release
mechanism previously mounted on top, forward of the
conning tower. Each pail contained an additional
thirty pounds of scrap iron. In the water, they would
be about twenty-five pounds each. They were rigged to
be released by pulling on a second line running to the
surface. I had a detailed system worked out with
smaller weights to precisely balance the sub but the
rough water made that impossible.
We hadn't released the air from the MBT's yet when we
realized that in the time it took us to prep the sub
we had drifted about a mile south in the wind and were
now in only 350 feet of water. The only thing we
could do was try dragging the weighted sub back up
north again. To our surprise, it seemed more stable
in tow with its extra weight. After approximately an
additional half hour tow, we were north of the dive
site so as to be on target when Persistence contacted
the bottom.
Once again I got back on the sub. I handed Al a line
from one weight pail and unscrewed the MBT plugs
releasing air. Al held up one weight pail with the
line from the boat. When the last of the air came
spurting out of the sub's main ballast tanks, the sub
seemed near neutral buoyant so we figured our weight
guess was close but it was difficult to tell exactly
how close in the rough water.
The plan called for the sub to be neutral buoyant with
all the fixed weight and one weight pail. The second
weight pail would make it twenty-five pounds heavy and
when we dropped them both off after the test, the sub
should become twenty-five pounds light and return to
the surface. Good plan! All we had to do now is
accomplish it in this rough water and not get our ½
inch poly retrieval line tangled in our smaller
release line.
Al released the second pail and the girls held onto
the lines. The sub started going down as I climbed
back into the boat. OK, Start timing! We were paying
out both lines faster then I had expected. Kathy
manned the spool of poly line and Christine reeled out
the weight release line. Before we started with the
test, I marked the line with colored coded tape at
fifty-foot increments.
Before attempting this test I did some experimenting
in a nearby shallow lake, I figured it should take the
sub about fifteen minuets to reach the bottom. Now
we found ourselves paying out both lines really fast
but they were going at an angle of about forty-five
degrees aft. We could stop the decent but not without
gloves on. The wind was dragging us down the lake as
fast as the sub we descending. To counter act this,
Al periodically ran the boat in reverse to try to hold
location. It was a fight as we paid out line and
avoided the boat's prop. Eventually the sub seemed to
stop taking down the lines. We had just gone past the
550 foot mark on the main line. We backed again to
where the line was about vertical. We figured the sub
was about 540 feet down. A mere stepladder's reach
from where it was supposed to be. Now for the wait!
For about ten minuets we held on to both the weight
release line and the sub retrieval line trying to keep
them apart. In that ten minuets Al had to back the
boat up three times to prevent dragging the sub across
the bottom. We feared dragging the sub may cause it
to get entangled with whatever might be lurking down
there. After the third time backing, Christine
suggested we tie the lines to boat fenders and toss
them in the water. I was having a difficult time
parting with the poly line in my hands, knowing it was
the only life line to my Persistence. I dreaded the
thoughts of getting it entangled down that deep. In
my original plan for the test, I thought I would hold
the poly retrieval line in my hand and tug the sub off
the bottom every few minutes, just in case it was
gaining weight from a slow leak. With the rough water
this was impossible anyway. We attached the fender
floats and over the side they went.
We were still getting blown south, down the lake. We
would ride it down a ways, then power up and go back
northward to drift past the floats again. This was no
hurricane we were dealing with but it sure wasn't
smooth water either. After countless passes up and
down and me asking constantly asking how many minutes
have passed, we finally reached forty-five minutes.
The sub was supposed to stay down there for sixty
minutes but without having a line in my hand to yank
on to check if Persistence was ever coming back up, I
couldn't take the wait any longer. I said, "Let's
head back and start the retrieval. It will take us
the next fifteen minutes to get it off the bottom
anyway." Al was heading over to the floats slowly for
us to retrieve them when the wing caught the boat and
sent it floating right over the line. The line
snagged the stern drive. SCUBA Al to the rescue!
Christine took the wheel and Al went down under to
free the line.
With Al back on board and holding the retrieval line,
I started pulling up on the release line. I pulled
and pulled, stretching the small line as it came up
but it only got harder to pull. I thought surely it's
caught on something. I only hoped it was the sub and
not a sunken tree branch or worse. With releasing the
weights not an option, the only thing to try is
pulling the sub up by hand. The sub went down fast so
I knew it was heavier then the twenty-five pounds it
was supposed to be. Al and I pulled on the poly
retrieval line hand over hand. We were gaining line
but it was difficult to tell if we were pulling the
sub across the bottom, the boat backward toward the
sub, stretching the line, or raising the sub from the
bottom as we hoped. After we pulled fifty feet of
line up, we both thought it was a good sign. One of
us alone couldn't have raised it but pulling together
and using the boats up and down motion to our
advantage, we were gaining on it. At the next fifty
foot mark we had to stop and rest. We continued
pulling and resting until we got to the three hundred
foot mark where we found the problem with the release
line.
Apparently as the sub was going down, maybe because of
the twisted braids in the line, it revolved around
about eight times, all in the length of five feet. We
unwrapped eight turns of the release line wound around
the retrieving line. Once it was freed, I again
pulled the release line in and after it stretched a
bit, it popped free. Instantly the poly retrieval
line became slack and we knew the weights had come
off. We started winding them both in slowly.
Slowly but finally, Persistence was coming home on her
own. We spent several minutes watching the angle of
the yellow poly line moving closer to horizontal.
Following its direction, we eventually saw a blurred
yellow submarine rising its last few feet to the
surface of Seneca Lake about seventy feet behind us..
What a sight! Once at the surface it bobbed around
like a beautiful yellow cork. The temporary red
external hatch holddown fixtures were about all that
actually broke the surface but its buoyancy didn't
matter now. It was on top.
Al, being a much better swimmer then I and also a nice
guy, got into the water once again. I handed two pipe
plugs down to him and he swam over to the sub to
temporarily cap off the MBTs. After doing that
without sending any pipe caps to the lake bottom, I
handed down a SCUBA tank tied to another boat fender
for a little extra buoyancy. Al took the tank and
swam over to the sub again, submerged himself and the
tank, then gave a shot of air up under the open bottom
of the aft MBT. The sub instantly got higher in the
water. He did this three more times moving between
the aft MBT and the forward MBT. With the sub now on
top and riding as it should be, Al connected the
towline once again and climbed back aboard the boat.
All that tossing and turning in the rough water didn't
seem to affect Persistence nearly as much as it did
our crew. If you notice, there hasn't been much said
in the later part of this story about my wife Kathy or
my photographer cousin Ted. They weren't actually
green yet and we still wouldn't know what they last
ate without asking, but they didn't look happy
anymore. It was time to head for shore and it was
nothing so soon for Kathy and Ted.
With Persistence tied behind, Al started up the boat
and we headed south, the way the wind has been telling
us to go all day. After the test, Persistence seemed
proven tougher now and we didn't hesitate to put a bit
more throttle to the boat pulling her. Al's boat was
taking her south and Persistence had no choice but
oblige. It followed like the full grown duck it had
been proven to be, throwing off a wake that at times
would splash over the hatch cover. Now it is a real
proven, three hundred and fifty foot diving sub, and
proud of it!
Upon returning, we unhooked the towline and I climbed
aboard Persistence for a trip through the marina and
to the launch ramp, under her own power. We loaded
both the sub and boat on their respective trailers
under the watchful eye of the usual many on lookers
and answered the usual bunch of questions with the
usual bunch of answers. Only this time we could say
"it went to 540 feet" instead of "its supposed to be
able to go to 540 feet."
After we left the marina, we went to a nice restaurant
up on the western mountain that borders the lake, just
outside of town. We talked, toasted the day's events,
and ate while watching the sun go down on the lake as
its surface was becoming more and more calm.
I want to thank the many folks that have helped make
my entire sub experience happen. Everyone, starting
with some of you in PSUBS that have guided me through
parts of the building, you computer guys that make
PSUBS happen, Captain Kittredge for his expert
guidance, John Maynard who sold me the plans and
visited at the lake, my crew that followed me through
this project and others like it, and most of all, Al
Secor who has been there when his diving skills and
boat were needed most.
Thanks a lot, all!
Dan Hryhorcoff
__________________________________
Yahoo! Mail - PC Magazine Editors' Choice 2005
http://mail.yahoo.com
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