Author Topic: Replace non-functioning DataMarine knotmeter & depth sounder.  (Read 18405 times)

wsgodlewski

  • P323
  • Newbie
  • *
  • Posts: 5
  • Karma: 0
    • View Profile
  • Model: P323
Replace non-functioning DataMarine knotmeter & depth sounder.
« on: February 13, 2012, 09:13:52 AM »
I have a Pearson 323 1980 model. I need to replace non-functioning DataMarine knotmeter & depth sounder (thru hull transducers). Any suggestions, money is always an issue. 

Dolce_Vita

  • P323
  • Hero Member
  • *
  • Posts: 563
  • Karma: 9
    • View Profile
    • S/V Dolce Vita
  • Model: P323
  • Vessel Name: Dolce Vita
  • City: Pasadena
  • State: MD
Re: Replace non-functioning DataMarine knotmeter & depth sounder.
« Reply #1 on: February 13, 2012, 11:42:50 AM »
First, are you sure you have to replace them?   Transducers are pretty reliable and rarely fail.
It's usually the wiring or the gauge.

The likely source of trouble is corrosion.  Commonest problem is the wire splices and end terminals,
although sometimes the gauge itself (usually a switch contact) will fail. But it's well worth
checking the wiring first.

Go over every foot of wire from the transducer to the gauge, and the gauge to the power
distribution and ground.  Pay particular attention to any butt splices.  Green corrosion is
an almost sure sign of trouble.  Look for nicks and cuts in the wire's insulation too.

Tug on each connection.  If it comes apart, it was bad. Many times I've had the connection
crumble and the wire fall apart when tracking down the cause of a non-functional piece of
equipment.  Cut out any suspect splices and terminals and replace them.  Be sure to strip
the wire back to good clean uncorroded metal.  Scrape the wire to bare clean metal if
shortening it is impractical. 

Use uninsulated butt-splices and ring terminals, and put two side-by-side crimps on them
if you can. Insulate them with adhesive-lined shrink tubing.  I find I get a much better crimp
on the uninsulated connectors, and the the heat-shrink tubing seals better onto them because
they dont have the large nylon insulator to get over.  If you get a good, watertight seal, the
connection should last for a long time.

Check that power is actually getting to the gauge.  Commonest sources of sources of
problems here are the fuse ans switch on the power panel.

If after all this, it still doesn't work, you may be able to score an old one off of Craig's list
that someone has replaced with a newer model.  Or you may be able to find a different
brand that is compatible with the transducer, making it an easy swap-out.

The parts and tools you need are all available from Defender, or, if you're in a hurry
and don't mind paying more, locally from a West Marine store.  Their cost will be far
less than a whole new gauge.

If the electrical skills are beyond what you want to tackle, perhaps you can get someone
to help.  Where are you located? Maybe one of this board's members are nearby.
@(^.^)@  Ed
1977 P-323 #42 "Dolce Vita"
with rebuilt Atomic-4

selene

  • P323
  • Hero Member
  • *
  • Posts: 376
  • Karma: 6
  • Mighty Member
    • View Profile
  • Model: P323
  • Vessel Name: Selene
  • City: Redwood City
  • State: CA
Re: Replace non-functioning DataMarine knotmeter & depth sounder.
« Reply #2 on: February 14, 2012, 10:59:58 AM »
I'm 1980 too....anyway, Ed's advice is always sound!  For the knotmeter, I assume you have tried the basics - removing it, spinning by hand, seeing if anything registers?

I had a similar problem.  I had problems with my electrics, which I fixed. uh...you found the second on/off switch? My boat had two, one on the main panel, one an the companionway. Caught me out at first, especially as there was a wiring problem between the two (loose connection came apart when tugged). The instruments then displayed, but nothing past zero.

My knotmeter issue was caused by a little sea-critter setting up home there. Gently relocated.  My transducer, however,was dead.  I was very tempted to replace the lot with a new set (Raymarine ST-60), but in addition to the cost (~$1500) that would have required a lot of work, as they are slightly smaller than the Datamarine so the current holes would have been too big.  In the end I found DMI Marine (http://www.dmimarine.com/), set up by a guy who used to work for Datamarine, and bought up lots of parts/spares etc.  Specialises in repairing old Datamarine kit. He can repair/recondition our old instruments, and I believe also has his own range which are exactly the same dimensions.  He ain't cheap - maybe $150 to recondition my depth display, plus the cost of a new transducer - but it was cheaper than a new set, and works fine (for now).

Incidentally, I set up my transducer in an oil bath, to work through the hull.  No haulout required - my old trandsucer, now dead, remains glued in its through-hull beside it.  Works fine, and should be a snap to replace. Also, I have been reading about solid-state knotmeters...they are expensive, and I know nothing about how they work; just seemed kinda cool as I am eternally cleaning "stuff" out of my paddle wheels!

(Disclaimer: Not associated with DMI Marine.  Just a happy customer)