Stowe to nasa depth transducer help !!!

[maha]

Hi All
i wonder if any body can help,

I have recently purchased a nasa duet for my sadler 29,

I want to replace to old stowe gear does any one know if i can use the old transducer from to stowe to work on the new nasa as the nasa has a read through the hull transducer and the stowe is isnt .

Or does nasa do a skin fitting for there tranducer i have fears of having to leave the existing one in and disconnecting it and positioning the new one next to it. (yuk)

There is only a small area to fit this in as it is a foam filled hull so i cannot put it anywhere else.


Any help or advice would be thankfully received,


regards malc

 

[Lance]

Hi maha

I don't think mounting the trancducer inside the hull is an option with a foam filled hull as the foam construction has a different density to water.

Next point might seem a little "Heath Robinson" but in my experience, transducers of different makes are almost the same and will either work perfectly or not at all. Why not try the existing transducer with shiney new duet?

Lance

 

[sailorman]

Hull isnt foam filled, just the cavities between the inner moulding & hull.
hull lay-up is solid

 

[VicMallows]

No problem with depth transducer inside hull on Sadler 29. Recently replaced an old Seafarer with NASA duet. Both 150kHz tranducers, though in my case it was transducer that had failed. Pretty sure STOWE was also 150kHz. Bigger problem is paddle wheel, which in my case is smaller than previous NAVICO unit!

Vic

 

[Gordonmc]

The Stowe kit I had used Airmar transducers. Take a look at the Airmar website which has a PDF document with applications for its units. It might help to look on the cable which should have a label with the type number.
You can then check for compatibility with the NASA head.
As an illustration, I looked up my transducer type and found it would work with a Raymarine ST50 triducer head, which I bought second hand. The koral of the story was that it was easier to get a new head than replace the transducer with a smaller OD unit in a wooden hull.

 

[Guest]

You know what depth you are in alongside berth or on mooring ? Plug stowe to nasa and check if it reads ok ...

Many are interchangeable - despite the blurb. Seafarer and Nasa certainly - as I have changed 3 boats with them ...

If the plug fits and depth indicates ok - go for it .... you can always sidle up to a tide gauge as well and check out there ....

Just make sure over a range of depths though - it may be correct at one - but wrong at another. Another reason to use a tide gauge as indication ....

 

[VicMallows]

*** Just make sure over a range of depths though - it may be correct at one - but wrong at another. Another reason to use a tide gauge as indication ***

Why? ... except at the very limit of maximum depth detectable, which may well change, but should be obvious?

Vic

 

[Guest]

To make sure that the combination of Stowe bits and Nasa are compatible ...... what may coincide at one depth may be out of synch at another .....

I know its unlikely - but I would like to be sure .... unless of course you have another way to check ...

If you put Nasa with Nasa, stowe with stowe etc. - then no problem and not necessary to check .... but you never know when you mix 'em !!

 

[tyce]

bugger,
i have just cut thro my stowe transducer wire to use as a mousing line for my new nasa transducer, is there any way of rejoining the wire to see if the stowe is compatible with nasa

 

[JKay]

Vic I've got a seafarer and all the lights on the perimeter stay on ,not showing a depth at all did your's show the same symptoms when the transducer died???

cheers Joe

 

[VicMallows]

Are we playing or serious? If serious will compose a response tomorrow, since have an idea what you might be on about,

Vic

 

[JKay]

Serious !!!Am about to replace with a garmin 160 . The head unit seems to work fine it's symptons are as if there's no signal to it.

On a lighter note if I was joking I'd start with "why did the chicken"

cheers Vic /forums/images/graemlins/wink.gif

 

[Guest]

of course its only normally coax - so others will poo-poo the idea - but a standard tv co-ax joiner will do it ..... looks like a tube, which is split in half and cables come in at ends and screw contacts for the centre lead, crimp for the outer .....
failing that - male and female tv coax plugs .... !! /forums/images/graemlins/shocked.gif

 

[VicMallows]

No need even to go that far. Just twist or solder the inners, insulate, and join the braids. If you want wrap foil around (but it wont make any difference) before insulating the whole thing.

They operate at 150 or 200 kHZ and impedance match is quite immaterial. Same technique will work perfectly at VHF frequencies, and at UHF if you do it carefully (in fact better than cheap TV type connectors) . (Must be a 'straight' in-line join).

Vic

 

[Guest]

cable joins ..

I do that - twiddle leads together and solder - but thought I would cater for the 'experts' on the forum by using a connector !!

Actually have used BNC connectors, TV connectors - anything literally handy to do this sort of job .... my VHF antennae on mast was via BNC to allow me to disconnect and drop mast on a previous boat .... connectors were greased and wrapped in tape and lasted years .....
The beauty of using connectors - is that you can disconnect so easily without cutting etc.

 

[milltech]

Both transducers will either read through the hull or be mounted directly in the water, it just depends how the first installer chose to mount it. Of course some hulls aren't suited to in-hull fixing, wood and steel for a start, but the same transducer functions in all installation unless it is very specific, like transom mounting for speedboats.

In its later years Nasa made Seafarers transducers anyway, and all 150 khz transducers should be interchangeable. Companies with aspirations to sell in the USA changed to 200 khz because it was what the American market favoured, but early British examples and current Nasa production will all be 150 khz. Check the Internet for a specification on your model or ask the question here. It's not that unusual, for example, for someone using a 200 khz depth sounder to go to airmar for a non standard transducer to suit their particular purpose.

Nasa does not do a skin fitting for the transducer, the procedure on a wood or steel hull would be to make a hole the size of the threaded transducer shaft and feed the cable in from the outside, seal the bulb of the transucer and bolt in snug from inside. Of course then you have an inch and a bit of plastic sticking out into the oggin, so you make up a fairing to go around this both to smooth its passage through the water and also to protect it from breaking away in an impact with something underwater.

(Please note all advice is the result of hearsay after 15 years in the marine industry, almost none of the installation type things I talk about have I actually done myself, I just sell the boxes, so request proper technical advice before acting).