Speed Transducer - Can I solder? How?

[MarkJ]

Hi Folks

Here is a job that has been on the list.
The speed transducer has stopped a while ago.
Raymarine guy was here recently and he said buy a new one.

The wire that looks like it is broken has a tiny section of bare wire.

It is too close to the unit to easily solder the joint.

How can I dismantle the transducer to get extra length of wire?

Should I just give up and go spend money on a new one?


Thanks for your advice!


Mark

[westsail42]

Of course you do not want to shorten the cable if at all possible as it may throw off the calibration.

Are are lots of strands in that exposed wire broken? If not, I would just seal it up with some liquid electrical tape and/or heat shrink and call it good. I cant tell by your picture but xducrs are often "potted" and cant be dissasembled.

If you can easily open up yours to expose more wire and seal it up, I would give it a shot.

Edit: sorry, speed ducers (paddle wheel type) can usually be cut, I was thinking depth ducers.

[Pblais]

The problem will be that connecting a new wire can easily break again. If you could disassemble the unit you could pacth the wire and maybe wrap it in heat shrink tubing and it would be fine. Putting the transducer back togther might be the problem. You just know it will crack badly before you try to fix it. But what have you to lose? Busted a little or trashed all the way no loss there. Perhaps cut away on the other side of the pull ring and then maybe expoxy it back togther.

You might check our Airmar Airmar Marine Products Home Page as they make many if not most of the transducers. The little flippers on the wheel tend to go bad and they quit spinning well after a while too.

[Minggat]

I bought a Garmin chartplotter with dept & speed tansducer. I fell victim to the salesman. Speed never worked and depth quit in short order. I felt like I wanted the speed because the unit was capable of it and I paid for it. I took it back and got full credit towards a Raymarine unit, also with speed capability. But unless I decide I want to start racing, the speed on either of my GPS units is better than the thru hull paddlewheel. I now have 2 in hull depth transducers and am happy with that.

Sorry to shift the thread. But it might be a good time to rid yourself of a thru hull.

[bene505]

On the other hand, having a speed transducer is (when you also have a GPS to show speed), is a great way to determine if you are sailing with or against a current. And knowing about a current is a good thing.

Good thread. I'm not that far behind you replacing mine.

Originally Posted by Minggat

I bought a Garmin chartplotter with dept & speed tansducer. I fell victim to the salesman. Speed never worked and depth quit in short order. I felt like I wanted the speed because the unit was capable of it and I paid for it. I took it back and got full credit towards a Raymarine unit, also with speed capability. But unless I decide I want to start racing, the speed on either of my GPS units is better than the thru hull paddlewheel. I now have 2 in hull depth transducers and am happy with that.

Sorry to shift the thread. But it might be a good time to rid yourself of a thru hull.

[David M]

Paddle wheels are horribly inaccurate. GPS cannot take into account current or leeway. Really the only way to accurately measure the boats speed through the water is with a sonic device. Airmar makes a sonic speed indicator. The speed indicator has two beams. It measures speed by measuring the time it takes a particle to pass from one beam to the other. Knowing the distance between the beam, it then calculates speed down to one tenth of a knot. I installed one last week on my boat. I have yet to use it for "technical reasons". My hydraulic steering pump went out and I have not been able to get the boat underway since I installed the unit. When I do get it working, I will report back.

AIRMAR Electronic Catalog

[RBEmerson]

The only impediment to repairing the connections is the potting compound. If you can excavate enough of it to expose the wiring well enough to ...ah... clean up the loose ends, by all means go for it! Paddlewheel sensors won't suffer from shortened or altered cabling as long as the connections are clean and tight. And it helps to connect the right wires to each other, of course. Once you verify the job's done, be sure to re-pot the connections or you'll have newly corroded connections - Bad Thing. I'd drown everything in Life Caulk, not silicon.

[GordMay]

Originally Posted by David M

...Really the only way to accurately measure the boats speed through the water is with a sonic device. Airmar makes a sonic speed indicator. The speed indicator has two beams. It measures speed by measuring the time it takes a particle to pass from one beam to the other. Knowing the distance between the beam, it then calculates speed down to one tenth of a knot...
AIRMAR Electronic Catalog
AIRMAR Electronic Catalog

Airmar CS4500 Ultrasonic Speed/Temperature Sensor
http://www.airmartechnology.com/uplo...res/CS4500.pdf

http://www.airmartechnology.com/uplo.../17-263-01.pdf

http://www.airmartechnology.com/uplo.../17-263-01.pdf

Compatible with (models noted):
Brookes and Gatehouse (B&G), Furuno, Raymarine (Autohelm) , Simrad, & Tacktick.

Form Response

[RBEmerson]

Much to be said for ultrasonic sensors, of course, but it also helps to remember that sensor location plays a major part in the accuracy of the system. Water flow over a keel is much like a wing and that means it's accelerated on the "high" side of the "wing", causing VTW to appear higher than when the boat's on the other tack and the sensor is now on the "slow" low pressure side.

The general recommendation is to position the sensor about a third of the way between the keel and waterline to minimize the problem cited above. General hull design and interior layout, however, may preclude this, leaving the sensor too close to the keel (resulting in "slow" and "fast" readings depending on the tack and transducer location) or too close to the waterline, bringing a host of problems including the sensor periodically coming out of the water.

Nobody ever said boats was easy...

[MarkJ]

The ultra sonic one I saw on the net was $1,500!!

[MarkJ]

Sucks-sess!!!

Well it was a bit of a job!

Nicolles dad arrived Friday night - he thought it was for a nice weekend abord Sea Life! Little did he know..... My off hand question at dinner about the skills of micro surgeons and solderers....

Though never been on a boat before Nics Dad is a farm irrigation installer so was happy to have a go...

The photo below is quite large so if you want to have a good look I hope it will help.

The white silicon was a mistake explained below.

Had the Raymarine speed transducer been removed before hauling out and placed on the door jam, then the door slammed closed?

1) The Green wire (see photo in first post) was clearly exposed. The difficulty in fixing the Green wire was getting enough length of wire to solder together.

2) The plastic at the top of the transducer was boldly cut away from the ring-pull using a drill and hacksaw to enable the whole wire bundle to be moved down and across. This gave enough extra wire to work with - not much, but enough for someone skilled. We didn't have to cut through any potting compound etc.

3) The green wire was soldered together but the unit didn't work.
The Unshielded wire was then connected and the unit worked and so we filled it with silicon.

4) The unit then didnt work

5) We removed the silicon and the White wire looked damaged. I don't know if the damage happened in the initial injury or with us working on it, but I guess it was in the initial 'door slam'

6) The soldered the white wire and the unit worked.

7) We refilled it with Silicon.

It goes in the water tomorrow.

What I learned: Yes you can fix a Raymarine speed transducer. Yes you can reconnect, solder, cut Raymarine speed transducer cables and wires.

Yes, you can cut the top off it too.

I don't know about the calibration stuff but I will check when we get it back in the water but we only lost a centimetre or 2 of wire length so it can't really affect it.

The unshielded wire is important.

(I have written this up for you guys and for those searching using Google etc)

The soldering job was far too difficult for me an Nics dad is quite experienced with fine work.

Crossed fingers for tomorrow!

Mark

[RBEmerson]

Congratulations on the successful surgery! Don't sweat changing the length of the wire, that's only an issue for depthfinders.

[Celestialsailor]

Mark...I got to be honest with ya...There's not much separating that plastic from the Ocean coming in your boat. Be sure you pot it up good. If i had a crystal ball. I would say paddle-wheel knot meters are going to go by the way of the Dodo bird. David M touched on it about the accuracy of a GPS. I don't know why more people don't rely on it. To me the knot meter is just another hole in the boat.

[Pblais]

I would say paddle-wheel knot meters are going to go by the way of the Dodo bird.

Pretty much. I've owned two boats both had marginal ST50 knot meters. They just don't hold up for long periods of time unless you don't install them.

[RBEmerson]

People, people, people... VTW is not SOG. Those who think they're always the same thing need to spend some time studying, on the water and not in an easy chair, the meaning of "set and drift".