RE: [PSUBS-MAILIST] faq page

[Alec Smyth <Asmyth@changepoint.com>]

Seriously, I do think Carsten made a post some time ago which would make a
hell of a good start. I saved it, so I'll paste it below.

-Alec

---------------------
From: MerlinSub@t-online.de
Sent: Monday, September 18, 2000 3:23 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Questions, questions and more questions

Hi Anthony.. some answers..

TeslaTony@aol.com schrieb:
> 
> This is a list of a few questions that I have for building a sub, I don't
> need exact info on everything just yet but I eventually will need them.
> 
> 1. How much space does the life support system take up (O2 tanks,
scrubber,
> etc.)?

You need at least 0,25 Liter/minute O2 each person 

Acorrding to the rules (GL 1988 Chapter 2 submersibles) 

- in two undependable storage groups
- best storage place is outside the hull 

- minimum running time for one-man subs should be 72 hours
- minimum run time for small subs should be 96 hours
- minimum run time for autonomus subs should be 168 hours

So for a one person sub it should be 
72 hours x 60 minutes x 0,25 Liters = 1080 Liters
1080 divided by a storage pressure of 220 bar = 4,9 Liters
4,9 divided by two groups = 2,5 Liter each bottle. 

And for a two person sub: 
96 h x 60 x 0,25 = 1440 Liter x 2 persons = 2880 Liter
2880 / 220 = 13 Liter / by two bottles = 6,5 liter each. 

The CO2 absorber depents on the used material but the general rules are
: 
- CO2 partial pressure should be between 0,005 bar - 0,01 bar each time.
- CO2 production of each person should be calculate with 20 Liter/hour
  for each person at 20°C and 1 bar atmosphere. 
- At the end of the O2 run time the CO2 pressure should be under 0,02
bar
  inside the vessel

- I think a scuba rescue system should be also in each PSUB for each
person..

Without O2 support the air inside you hull will fit you about 20-60
Minutes
depents on the size of your pressure hull. 
You can test this time on your finished pressure hull very easily if 
close the hutch with you inside (which should be possible to open from
the outside)
and somebody outside.

Starting the clock and wait - if the headeages get to high you have CO2
poision
and this last air reserve is over. If you fall in coma your
wife/friend/girl
should open the hutch.. Time in Sgt.Peppers was 40 Minutes..

> 
> 2. Where is a good place to put the motors, inside the main hull or
outside
> in a secondary hull?

Depends on the design. Sgt.Peppers for example has all 5 motors outside
for 
some reasons. I want a sub with a small displacement - so I want a small 
pressure hull. CSSX for example will be the main engines and most
equipment 
inside because of maintance the motors with the sub in the water. 
In General : Thrusters outside, non-electric main engines like diesels
inside. In smaller boats with only a electric main-engines maybe
outside. 

> 
> 3. Does anyone know anything about using jets from a jetski to propel the
sub
> or is this totally new territory?

The efficency of a jetski drive is lower than a propeller drive at low
speed. 
But for high speed sub it can be usefull. Cousteau use some kind of
water jet
pump nozzels in his early flying saucers. But listen there is no jetski
drive
on the market with a high-pressure proof seal on the axis - ( or ??) 

> 
> 4. What kind of controller arrangement does everyone have? (A simplified
> version of this question would be "What does you dashboard and steering
wheel
> look like?")

I use two arcarde- joysticks in one box to control all four thrusters
and one 
orginal Minkota-controler for the main engine in Sgt.Peppers.
But this depents on your own expirence - a EMM (electronic-mad-man) will
be control
his sub with a laptop, a steel-man with some kind of gear and maybe long
steel pipes etc..
Cssx will be a electric aircraft steering system for the rudder and a
simple four 
step switch four the electric main engine. For the diesel and the side
rudder
will be a second station as joystick which I can give up to the hutch to
the outside 
sail to control the sub on the surface or inside the harbour. 
(Sgt.Peppers joystick-box can be also use from outside the hatch - the
cable is a little
longer than its needs..) 

> 
> 5. How are the things that need holes in the hull made so that they don't
> leak or compromise the safety of the sub?

Hmm.. Let me think - one hole for each motor cable .- one hole for VHF
Antenna
two holes for main battery cable, two for the lamps, one for the drop
weight release, 
One big one for the front window, one for the entrance, 
5 for the ballast tank-air-out/in pipes, 2 for the regulator, 
one for the snorckel : about 21 holes in Sgt.Peppers.. most for cables. 
There are some good description on "Manned Submersibles". 
All holes tighted by different design of o-rings. 

> 
> 6. Can the gas in the ballast tanks be allowed to just bubble off into the
> water to sink and then be replenished from a CO2 cylinder or other gas
tank
> or should there be a compressor to pump the gas from the ballast tanks
into a
> pressure vessel onboard?

Just bubble outside - is the normal way, replenished from a air tank, 
which can be filled with a normal scuba-compressor. The compressor
should be
onshore on smaller subs. Bigger subs have them inside but this make only
sence
in combination with a diesel. There is no reason to have a compressor on
board
of a electric-only driven sub. You lost the space for the compressor,
for
aditional batteries - put a bigger pressure bottle to the sub is much
simpler
and more safe. 
CSSX will only use a small amout of air to start blowing the ballast
tanks. 
If the submarine is surfaced with just the sail the diesel will run and
blow the 
tanks empty with his exhaust gases to safe compressor run time.  

> 
> 7. If I can't get a copy of "Manned Submersibles," what other book(s) can
I
> use?

"Manned submarines" is a very good starter. "Jane's Ocean Technology
1978" is also
a good source. Some books about simple metal technology and Physik will
also help.

> 
> 8. I have noticed that other subs that I have seen seem to be unusually
heavy
> as well as unusually expensive (such as one sub that weighed 3.5 tons, was
8
> feet long and cost $100,000), why is this?

Depents on your specification. 
How many person, how long, speed, range, diver look out or not. 

For a Psub a good size is a two persons steel sub which can be driven 
on a trailer behind your pickup. Around 2 tons should be fit the most 
specifications. Sgt.Peppers with only 0,65 t is clear a midget version
of a midget. I was last week in the museum and listen to a guy which
explain
to his child that it is maybe only a model of a sub...

A Kittredge size sub should be possible for about 15.000 Dollar for the
material
and some foreign working hours. Sgt.Peppers material was around 7.000
Dollar 
including the trailer and the battery charger. CSSX will be play in a
other class..

If you have no expirence with steel - maybe work for one/two weeks as
help-mate 
in a metal-shop (during you free-time or holiday or payed). 

Pat is right - steel is unexpensive and simple to handle. 
I can use both steel and reinforced GRP / GFK and I like 
the steel. I calculate with 0,5 Dollar for each Kilogramm (1/1000 t)
steel
if I work self and with 1,2 Dollar for each Kilogramm made ready to
use/build in
from a metal shop. For stainless steel it is much more - about 3 Dollar
if you work yourself - but weelding needs much more expirence. 

> 
> 9. What is a reasonable dive time for a Psub?

About 2-4 hours for a lake sub, up to 8 hours for a 
offshore Psub (My opinion..). One week for 4-5 person for a 
autonomous sub. CSSX will be surface all 12 hours to clean the inside
air (using the diesel via hatch as fan..) so it don't need the scrubber
 and the oxygen system in travel and search mode. In sitting on the
bottom 
and working mode on a wreck I will use it.  But supply with battery 
power should be 72/96 hours at least for the scrubber. 

> 
> 10. What is a reasonable dive depth?

Between 90 feet and 1300 feet depents on want do you want to do with the 
sub. Over 1300 feet everything get very expensive including the pressure
hull. 
For a private pleasure sub without a real operation idear - means just
for fun
300 feet should be okay - you can use standard valves and equipment from
the 
next harbour-shop. CSSX will be 820 feet because this is the area I
think diver
could work in the next 2-20 years and also the area of the
continental-shelf.

> 
> 11. How should the dome/hatch be sealed?

The dome will be fitted by a ring made from iron or stainless steel -
this 
should have a nut for a o-ring or a other rubber ring. The dome on
Sgt.Peppers
is sealed to this bajonet-ring with silicon-zement on the dome side and
with a 
o-ring on the pressure hull side. So I can blow the dome out with
overpressure
in the sub in emergency (if I sealed the overpressure vale..). But this
is clear
theoretical. 

> 
> 12. How does the emergency dropweight work? (I know the dropweight is
dropped
> in emergencies to surface, but how

Make a hole in the bottom of you pressure hull, put a axis in - sealed
with a o-ring.
Inside a key to turn the axis 90 degree left or right. Outside a flat
iron plate
longer than beam. A hole inside the drop weight more beam than long. Its
more or less
like a door key. Sgt.Peppers use a system with a axis with a screw
thread. 
Needs 10 times rotation and two springs press 8 outside horizontal bolts
out their
holes and the hole keel including the batteries and forward engines give
way. 
The cables on the engines has plugs which gives also way. You should use
the
simplest mechanical device for this rescue system.. And a Psub without a
dropweight
should maybe be not displayed as project on this list/homepage. 

> 
> 13. How can a periscope be used with a dome?

Look in the archive for "periscope" - there is no real reason for one. 
CSSX will get one in form of a video-camera in a acrylic mast - but more
for
underwater use and to reach the visibility-high on surface. 

Look for "Delfin" in the Picture Gallery to have a view to a not
nessesary
periskop...

> 
> 14. How about a snorkel for shallow runs?

No reason for that. Sgt.Peppers has a snorkel to safe O2 and scrubber on
the
surface if the wind blowes/waves  and I have to drive with closed hatch
because of
the low freeboard of this small vessel. Its a good idear for offshore
going small
subs to increase the freeboard - specially on subs with domes as
entrances. 
I use them also for "pre dive - all is tight" checks. Just blow out some
air from
the inside via my lungs to the snorckel. Shut vale and have a two
minutes look to the 
inside pressure indicator (barometer). 

> 
> 15. What kinds of lights are used for subs?
> 
Simple : Divers lamp, also simple - sealed beams from General Electric. 
every thing with a voltage of your main battery can do the job. But 
the front window of pressure box of the lamp should be made from a
material 
which can go hot on inside and cold on the outside same time.. 

> 16. Where can I get plans, kit or completed sonar? Is a sonar just a nifty
> little toy that isn't going to do me much good unless I'm off treasure
> hunting?

Its very useful - but a simple good one is expensive in the 4000-5000
Dollar range. 
CSXX will be one forward echosounder, one for the deep and maybe one
360° sonar or 
high resulutions echosounder on each side (use as side-scan-sonar) for
wreck hunting.
For a lake sub a good compass is the minimum of navigation equipment. My
compass 
works only on Sgt.Peppers if no engine is running..

> 
> 17. How are the maneuvering thrusters worked out? Is it one thruster that
can
> be swung around or is it multip;e stationary thrusters? How powerful are
they?

I like the fixed thruster - simpler to build - no turn around sealed
axis 
- but you need more thruster.. Looking in the archive for ..oil
compensation.. 
and for ..air pressure compensation.. If you use thruster with oil or
air compensation
you can use simple electric-outboards which are unexpensive. Sgt.Peppers
use
model-aircraft-petrolengine turn around starter which are very powerful
and small.
The pressure hull is self made from PVC - pressure pipes and endcaps.   
For fixed thruster which can change the propeller rotation direction are
very fast
in reaction time. A turn around thruster needs more time to handle and
more
equipment to turn and control them. 

> 
> 18. Which is better for a hull: New propane tank or getting some tubing
and
> two endcaps?

Look in the archive for the "propane tank". Its better too make a plan
from you sub which full-fill all your requirements. Than calculate the
pressure
hull - Its unexpensive to buy a new special for you made tubing and
endcaps. 
A propane tank will compromisse you sub to the given dimensions of the
tank -
means to big or to small - but in the most manners to low dive deep
because
of the small thickness of the material. The pressure hull is clear not
you main
problem .. not for the cost and not for the design..

> 
> 19. Should I put ribs in? If so, how do I make them?
> 

Ohh..ähmm.. ---- Depents on the dive deep and the thickness of your
tubing and 
the diameter of your tubing and the material of your tubing and.. 
First make a specification what your submarine should be doing for your
- 
than give the specifications to the group. In the most solutions you
need
ribs. Sgt.Peppers has no ribs but a small diameter of the tubing made
from
1/3 inch high density steel. If I put a single rib in it will increase
very
the dive deep  - maybe for using them as ROV ..
Some of the group can calculate this very quick for you - including me..

> 20. Are you trying to figure out what day it is because my list of
qustions
> is too long?

Its the 1.095.000 day - after my spaceship crash into the ocean of this
small planet
- and I must wait so long that the animals on this planet find out how a
wheel
work, steel is to make, or a diesel is working. But will maybe fly home
some weeks 
after CSSX is properly working. 

Sorry about my english - I am not from here. 

Carsten

> Anything I miss?
> 
> Anthony


-----Original Message-----
From: Ray Keefer [mailto:Ray.Keefer@west.sun.com]
Sent: Monday, November 27, 2000 1:50 PM
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] faq page


Hi Gang,

And now for something completely different.... I started a FAQ page.
It is currently on line at the web site.

I want you guys to submit basic questions and the answers to me and
I'll put them togethers on the page. I started with the two most
basic questions I get:

	How do I join
	How do I quit
	
Send me the ones you wanted ask back when you were just getting intersted.
That way we get the basics on paper, errr, in electronic form.

Regards,
Ray