[PSUBS-MAILIST] gyroscope/fluxgate compass

Tue Dec 9 02:37:25 EST 2014

Alan,

I have just a simple readout. But the compass sensor can be fed into more
sophisticated navigation electronics and can control a rudder actuator.

Emile

  _____  

Van: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org]
Namens Alan James via Personal_Submersibles
Verzonden: zondag 7 december 2014 19:32
Aan: Personal Submersibles General Discussion
Onderwerp: Re: [PSUBS-MAILIST] gyroscope/fluxgate compass

Hi Emile,

did you have it displaying on a Raymarine screen?

Can I feed this in to a plc & display it on a screen easily?

It is saying......

COMPASS

  Fluxgate Compass transducer to ST60+
<http://www.raymarine.com/uploadedImages/Products/Fishfinders/Transducers/In
strument_Transducers/fluxgate%20to%20ST60plus.jpg> 

SeaTalk1

The Fluxgate Compass transducer is compatible with the ST40 and ST60+
instruments on the SeaTalk1 network. The transducer simply connects to the
back of one of the following instruments:

*	ST40 Compass
*	ST60+ Compass

SeaTalkng

The Fluxgate Compass transducer is compatible with the
<http://www.raymarine.com/view/?id=1250> i70 ,
<http://www.raymarine.com/view/?id=621> ST70 and
<http://www.raymarine.com/view/?id=227> ST70+ instruments on the SeaTalkng
network via an  <http://www.raymarine.com/view/?id=3338> iTC-5 transducer
converter (sold separately). The transducer is connected to the iTC-5 which
converts the transducer signals to SeaTalkng. The iTC-5 is then connected to
your SeaTalkng backbone.

Note that if your system contains an SPX autopilot the Fluxgate Compass
should connect directly to the course computer and not the iTC-5.

Alan

  _____  

From: Emile van Essen via Personal_Submersibles
<personal_submersibles at psubs.org>
To: 'Personal Submersibles General Discussion'
<personal_submersibles at psubs.org> 
Sent: Monday, December 8, 2014 2:19 AM
Subject: Re: [PSUBS-MAILIST] gyroscope/fluxgate compass

I got good results with a (raymarine) fluxgate.  The sensor is placed in the
all aluminium bow section ( 0,9 Meter away from the hull) and the readout
can placed anywhere.

It can electronically compensate 10 or 12 deg deviation caused by the steel.
The sistership has the sensor in a short mast also with good results.

Attached a sketch of the pressuretight sensor housing.

Regards, Emile

  _____  

Van: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org]
Namens " Carsten Standfuß " via Personal_Submersibles
Verzonden: woensdag 3 december 2014 20:46
Aan: Personal Submersibles General Discussion
Onderwerp: Re: [PSUBS-MAILIST] gyroscope compass

Gyros in aricraft are not north stable - they need a magnetic compass or
other device to set course. But they are okay  if you set course according
to your GPS course before you dive. They can hold the course for some hours
with a movment of 2-4 deegre per hour. Okay for a slow and small Psub. They
are vaccum driven or electric. Vaccum driven you can not use in a small
submarine. (Or you need a silencer and eardrums as in Spurdog). Electric you
can use if it is a 12 or 24 V DC driven one. For other voltage you need a
special power converter. The Ebay units are sometimes cheap - between
100-800 USD - but most of them work not proper. They are build out of the
planes for exact that reason and sold as they are and without any waranty..
Size is around 100x100x400mm. Volume 4 Liters .. Good solution if you buy a
unit in aircraft condition with papers from a aircarft surplus dealer with a
working garanty. Make sure that they get not wet or 100% humidity. 

Gyros in ships are north stabilzed. The need around 40 Minutes to warm up.
They are much bigger - the smallest one are around 300 x 400 x 300 mm .
Volume at minimum 36 liter . They need no calibration or reference and they
are stable over month/years. Problem is that they normal switch on in a ship
and never switch off.. If you switch of them - make sure that you not move
the sub in the next hours - otherwise they can be damaged. They are
expensive - about 30000 USD new and 3000-9000 USD second hand.  There life
time is limited 30000 -  40000 hours between first failtures. 

I have both types in the Euronaut. And a magnetic one also. 
The gyros are both cheap Ebay ones. One from a aircraft one from a ship. 
And both not working anymore. And the third magnetic one has a big error
because of the 60 ts steel below. 

I will by next a second hand one north stabilzed ship gyro for around 3000
USD from a ship scrap yard electronic dealer with a confirm that they test
it and its run stable but without any further waranty. 

A fluxgate its a kind of electronic coils magnetic field compass and will in
most cases not work proper on a strong magnetic metal shell like a submarine
with strong electric motor fields etc. To test on your submarine if these
cheap devices runs on you submarine install a simple magnetic compass
temporary on the sensor spot in mind and than turn the submarine 360 degree.
Switch on and off all electric devices. 
Cross check with another compass (or the same  one) far away from the sub. 

In most cases an electric 12 or 24 V Dc driven Airplane direction gryro in
combination with a gps course before diving will do the job. But in 99% a
ebay 100 USD item will not work proper. 

vbr Carsten

"hank pronk via Personal_Submersibles" <personal_submersibles at psubs.org>
schrieb:
> 
> There are all kinds of them on ebay for under 100 dollars, problem is how
to make it work. I assume they just have a small motor that spins. There is
a nice ship gyro sitting at 50 dollars right now but it is about 1 foot dia.
That would be awesome in a big sub.
> Hank --------------------------------------------
> On Wed, 12/3/14, Alec Smyth via Personal_Submersibles
<personal_submersibles at psubs.org> wrote:
> 
> Subject: Re: [PSUBS-MAILIST] gyroscope compass
> To: "Personal Submersibles General Discussion"
<personal_submersibles at psubs.org>
> Received: Wednesday, December 3, 2014, 1:48 PM
> 
> Absolutely. You can get small ones for civil
> aviation and they are used in subs. One challenge is that
> most airplane ones are powered by a vacuum, but there are
> 12V models. Unfortunately they're expensive, but a great
> solution if you can afford it. 
> Alec 
> On Wed, Dec 3, 2014 at 1:28
> PM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org>
> wrote:
> Hi
> all,
> 
> Ever hear of a gyroscopic compass, seems that ships used to
> use them.  It seems they would not be effected by a
> submarine hull.  What am I missing besides they are very
> big.
> 
> Hank
> 
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