Re: [PSUBS-MAILIST] New Submarine Project... Need Input.

[lawrie@engineer.net.au]

Hi Bruce,

My name is Lawrie and I live on the east coast of Australia.

My background is that I am an environmental engineer with one year  
mechanical engineering and reasonable knowledge about fuild mechanics  
and hydrualics. I work at oil refineries during maintenance with  
fitters and turners, and boiler makers.  I am telling you this so you  
can gauge my advice from these perspectives.

I have built a few models and experimented with different hull shapes  
with a few to a 12 m boat or in the Queen's english a 40 footer for a  
sea going quest to our Artic waters south of here.

This is what I have found may fit your requirements generally.

Firstly, one might chose to use bioler plate steel which is a fine  
grain carbon steel with the right additives to make it heat workable  
and weldable. Heaps of companies around these days to press it into  
hemispheres from one piece.  In other words, not segmented.

The most economical hemisphere in terms of strengh, weight for length  
and beam of proposed boat is 1590 mm inside diameter of 20 mm  
thickness. Join the two halves with rolled steel section 40 mm of a  
width between the two of 600 mmm.

Forget about concern of weight because your building a big boat not a  
compact submarine.

This gives your central pressure vessel (crew compartment) an over  
length of length of 2200 mm which is approximately 1/3 of your overall  
displacement taking into account tapers at each end.

Make your hull at one third back from the bow oval of a beam of 2200  
mm and depth of 1600 mm with a draft of 1200 mm once I explain what  
else I have learnt form my models and calculations.  Noting of course  
that your hemispheres are at right angles to the keel and that a  
foward and aft hatch which are also horizontal take you into the  
forward and aft floatation (air) sections of your boat that are dry  
when surfaced.

Use your rolled mid section for placement of viewports and periscope.  
Onto top of your hull is your deck another 400 mm above which is thus  
800 mm above the water line. Build below your deck line over top of  
your floatation airs a wheel house section with plenty of windows and  
a large air tight hatchway to the top of your deck.

Keep your periscope, air intakes and outtakes and over items with a  
conning tow with a width of 400 mm leaving lots of room either side to  
move about the deck which is about 860 mm in width at its widest point.

For the bow and stern two spheres each of an inside diameter of 800 mm  
of 10 mm bioler plate steel which is the minimum that can be  
successfully heat molded with segmenting your pressure hull.  Fill  
each half full with oil and arrange a two way oil pump within your  
crew compartment to control trim.

When on the surface put all your oil in the stern pressure vessel to  
raise bow a little and when level submerged have the equal in each,  
and when diving most in the bow.  Forget about a forward plane you  
only need a stern one because unlike a compact submarine your long  
enough but not too long to control your boat using weight and a single  
stern plane.

My calculations show a diesel of 65 hp is sufficent for 8 knots surfaced.
House your motor in pressure vessel separate to everything else.  Have  
a single shaft and a four blade prop designed for about 1100 rpms.   
Have a swing in connection for a 25 hp electric motor which will get  
you about 6 knots when submerged just below the water.  Run your  
diesel at low rpm to keep the charge balanced with output.  Also keep  
your rpms for your prop at 1100 when running your electric motor.   
Suggest finding an electric motor designed for a tank turret. The one  
I have has great torque and consumption of energy is fair, not  
brilliant but very adequate for this arrangement.

Whales swim most efficiently at 6 foot below the surface and so will  
your boat so it makes up for the inefficency due to losses caused by a  
change from mechanical to electrical energy.

Use a snokle and run decks awashed and you will see your Island on  
less fuel than you can imagine.  Along the way take a dive. The hull  
and the right bits and pieces will give you comportable 200 m dive  
depth.

Best of luck in your design and let me know what you learn as well.

Cheers from Ozz, Lawrie





************************************************************************
************************************************************************
************************************************************************
The personal submersibles mailing list complies with the US Federal
CAN-SPAM Act of 2003.  Your email address appears in our database
because either you, or someone you know, requested you receive messages
from our organization.

If you want to be removed from this mailing list simply click on the
link below or send a blank email message to:
	removeme-personal_submersibles@psubs.org

Removal of your email address from this mailing list occurs by an
automated process and should be complete within five minutes of
our server receiving your request.

PSUBS.ORG
PO Box 53
Weare, NH  03281
603-529-1100
************************************************************************
************************************************************************
************************************************************************