RE: [PSUBS-MAILIST] New Submarine Project... p.s. from Lawrie inAustralia..

[lawrie@engineer.net.au]

Hi Dean,

Hey we might have enough numbers to start a chapter in Australia lol.

I have been reading a book Ubootwaffe which is about the German marine  
technology 1939 to 1945. Whilst the book is more historic it does  
contain a lot of useful details including the practical applications  
and reliability of the snorkle designs.

What I have come to realise is that the importance of the snorkle when  
not trying to be detected as in navy conflict, is simply to maintain  
air supply when the ocean get very rough.

Being in the oil industry we never rely on valves when dealing with  
high pressures.  So I have decided to have a first line shut off  
system a basic down turn U section of pipe with ball float, second  
line a manually operated valve located outside the pressure hull  
operated from the inside, and last line an end of pipe swing in blind  
that you bolt closed before diving. A combination of three controls.

The other thing I have learn from this book is that a lot of the  
miniature u-boats only had one shaft that the primary drive (diesel)  
was about 3 times the size of the DC motor and depending on the pitch  
of the prop and diameter the drive shaft to a three or four blade  
common prop ran at about 1000 rpm.

The use of thrusters is a great idea for slow speed control of the  
boat but for the getting from A to B whilst submerged as in the case  
of a bigger boat with a diesel the primary drive combination appears  
to be the best method.

For example, the Seehund vesssel was almost 12 m long and had about a  
12 m3 displacement without its torpedoes and with a 60 hp diesel and a  
25 hp DC motor did 7.7 knots on the surface and 6 knots submerged all  
off the same shaft which was pretty amazing. At 7 knots and 460 litres  
it had a range of 270 nautical miles !

I can mail the book to you if you look after it and promise to send it  
back to me if you like. It is very large and detailed.

Incidently I had another book written by another German fellow which  
was more about the engineering of U-boats but I lost that in a move  
and having a hard time finding one on account of forgetting the title  
and author's name which was Urgan or something???

Also there is a bloke who is an old school glass shaper that use to  
hand make optical instruments before the automatic machine and big  
business took his ancient trade away.  He lives in north Queensland  
and I am hoping to meet with him soon about building a prism glass and  
lens periscope for small craft application. If your interested in this  
please let me know. Maybe the cost of two or more is cheaper than a  
one off build.

Sorry for the long email, it is great to realise that others here have  
similar sub sea dream machines on their minds.

Cheers,

Lawrie.




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