Psub Design Steps

[SeaLordOne@aol.com]

Teammates,

Please excuse the cross posting, but I am hoping that both lists will find 
this posting useful.  I wrote it for the design sub-group, but I hope the 
main group will find it worthwhile.  I want to support both groups.  I 
welcome feedback (as though I have to ask for it).

I would like to take a crack at laying out the basic stages in psub design.  
I had hoped to watch a bunch of guys do this, and then write it all down, but 
I guess I will not be able to coast like that and stay on the design team.  
So let me take a stab at this.

Based on the few references I have read, here are my initial thoughts.  
Submarine design represents a series of increasingly detailed descriptions of 
the boat you will in time build to meet your unique needs.  You start with a 
blank sheet of paper, and you end up with detailed specifications, drawings, 
calculations, and notes. To do that, you go through a series of steps, 
answering somewhat different questions at each step. The process is 
self-correcting, so if you start to put the cart before the horse (as we did 
when we started to include specifications from the Busby Book before we even 
agreed to the basic "mission" of the boat), you catch it pretty quickly.  
Still, it is probably useful to walk through the process in a roughly 
sequential order.  The goal is not that all design features are in time 
deduced from your original mission statement, but that by the time you are 
done, the data you have documented at each step of the process is consistent 
with the information that precedes it.

I see the following stages;

1.  Review basic criteria (any design must be functional, affordable, and 
buildable)
2.  Validate the need (are you sure a sub is what you need to meet your 
needs?)
3.  Define the mission of the boat (what do I want to do with this boat?)
    A.  Mission statement (what are the things I want to do in this boat?)
    B.  Submission statement (what exactly will I do with this boat, mission 
by          mission?)
    C.  Unique requirements (what crazy things do I have my heart set on to 
do with         this boat?)
4.  Operational requirements (can I quantify these desires into measurable 
goals,  such as maximum depth, maximum range, and maximum speed?)
5.  Concept study (let me sketch out a few alternate drawings for a boat to 
meet    
    these requirements)
6.  Final Design (now that I have reviewed my concepts and selected [or 
integrated]     a final choice, let me run all of the calculations, develop 
detailed drawings, and  lay the whole design out on paper/software)
7.  Design Guide (let me add sufficient detail for any work I plan to 
contract out    rather than perform myself)

Now let me wax poetic on each of these steps (please indulge me here).

1.  Review basic criteria (any design must be functional, affordable, and 
buildable)

A submarine specification, like any engineered product. Should meet a few 
general criteria.  Unlike the features to follow in successive stages, which 
must often be balanced off against one another, these criteria must all be 
satisfied.  The design must be:

A.  Functional (the boat has to do everything that you want it to do)
B.  Buildable (you must be able to either perform, or to contract out, all of 
the tasks   required to (1) design, (2) build, (3) test, (4) operate and (5) 
maintain your boat.     You must also have access to all of the materials, 
tools, technology and   information required to perform those 5 basic 
functions)
C.  Affordable (you must have enough resources [money, time, intelligence, 
spousal     support, etc.] to compete all 5 functions)

2.  Validate the need (are you sure a sub is what you need to meet your 
needs?)

Be sure that before you run off and build a submarine, that you have ruled 
out other means to achieve your goal (glass-bottom boat, scuba lessons, hard 
hat, etc.).  I know that the members of this group are way beyond this step, 
but I suspect that there are plenty of wide-eyed romantics who dream of their 
own personal submarine, who might benefit from the inclusion of this step.  
In fact, one of my goals for developing a detailed "how to build a submarine" 
book is not simply to support the 1% who will actually complete the project, 
but to show the 99% who will not complete the project what they are getting 
into.

3.  Define the mission of the boat (what do I want to do with this boat?)

The primary focus here is on what you want the boat to do.  The secondary 
focus in on what you want it to look like or what special personal 
expectations you have for the boat.

    A.  Mission statement (what are the things I want to do in this boat?)

        What do you want to do with this boat?  Dive deep into the ocean, or 
poke        around in shallow lakes?  Perform high-speed aquabatics a la Deep 
Flight, or      do some slow, straight and level sight-seeing, a la the 
K-250?  Do you want         to do salvage work?  Diver support?  Racing?  
Oceanographic research?  Do         you want to fold in another hobby, like 
scuba diving or fishing?  Do you want       to be able to sit on the bottom?  
Travel long distances?  Visualize yourself in       your boat, doing every 
last little thing you want to do in that boat...the write it        all down.

    B.  Sub-Mission statement (what exactly will I do with this boat, mission 
by          mission?)

        Now look at each mission you listed, one at a time.  Can you add any 
more        detail?  Lets assume you want to do salvage work.  What do you 
want to             salvage?  Where do you want to salvage it from?  Will you 
locate, retrieve            and transport these items, or only locate them?  
Will you work in tandem             with a support boat, or will you work 
alone?  Add as much detail to each          mission and sub-mission as you 
can.

    C.  Unique requirements (what crazy things do I have my heart set on to 
do with         this boat?)

        What is on your special wish list?  Do you want to be able to sit on 
the             bottom and listen to Jimmy Buffett?  Do you want to make love 
on the ocean        floor?  Do you want to break some kind of Guiness Book of 
World's Records         record?  Do you want to fly the Jolly Roger?  
Psubbers are a unique lot, and      their private and unique goal should go 
into the design of their boats.

        Not all of these unique needs have to be wild and crazy.  Some will 
be          practical.  Do you want to certify this boat?  If so, with what 
organization?       What are their requirements?  Do you want to design this 
boat just for               yourself, or build it in such a way that you will 
be able to sell it when your            are through with it?  Will you allow 
for easy modification?  You could add           extra room in all areas, in 
case you want to add equipment, increase the            size of your motors, 
or add additional batteries in the future.  You could even      anticipate 
allowing for the addition of hull plugs, allowing you to add a few          
feet of hull fore and aft of your conning tower, increasing the length of 
your            boat without requiring a new hull.  This is the time to think 
ahead.

4.  Operational requirements (can I quantify these desires into measurable 
goals,  such as maximum depth, maximum range, and maximum speed?)

    Time to get as specific as possible  with the boat and with all of its 
systems and     equipment.  How deep will I dive, how long will I stay down, 
how fast will I go,     now far will I go?  If I plan to trailer, what are my 
weight constraints?  If I plan to   tow, what are my configuration 
requirements?  What constraints will my     launching and retrieval 
arrangements put on my design?  Specify and quantify    these requirements to 
the maximum extent possible, for the boat itself, and then  for each system 
(electrical, hydraulic, propulsion, navigation, control surfaces,   etc.)

5.  Concept study (let me sketch out a few alternate drawings for a boat to 
meet    
    these requirements)

    It is now time to sketch out a few alternative drawings of designs that 
will meet   this long list of specifications.  This is the time to be 
creative with alternatives.     Think outside of the box.  But do take these 
concepts all the way to numbers:    size, cost, performance, etc.  You will 
need that level of detail to decide which   one to go with (or which features 
to integrate into your final design).  This is time     to consider 
maintenance, reliability, fire, shock, noise, safety, maintenance, and  
operation.

6.  Final Design (now that I have reviewed my concepts and selected [or 
integrated]     a final choice, let me run all of the calculations, develop 
detailed drawings, and  lay the whole design out on paper/software)

    Now it is time to run all of the numbers to see if this design will work. 
 Structural     calculations, hydrodynamic efficiencies of motor-to-hull 
interactions, battery   performance, power requirements, size and location of 
control surfaces, location  and capacities of all tanks, assessment of 
weights, hydrostatic stability while    surfaced and submerged and 
transtioning, assessment of operation and   maintenance costs, etc.  What 
ever you need to verify your confidence in this     design.

7.  Design Guide (let me add sufficient detail for any work I plan to 
contract out    rather than perform myself)

    If you are in a position to do everything yourself, your design is 
probably done.      But if you plan to contract out aspects of the 
construction, you may need to add   additional detail to your specification.  
This will allow competing contractors to    bid on the work, as well as guide 
the work once the contact is awarded.

That is enough for tonight.  Stick me with a fork...I am done.  I hope that 
as the design group moves forward I will be able to improve on this purely 
theoretical model and in time develop a useful and practical design guide.  I 
would much rather have an expert do this, but until one steps forward, I will 
continue to plug along.

Doug