Transducer Removal Help Needed

Dean Abramson · Post by **Dean Abramson** » Mar 15th, '11, 18:08

I need to remove this dead depth transducer.

[img]http://www.mainephoto.com/folios/BoatDpthTrnsdcr-3.jpg[/img]

As you can see, I have gotten the nut off. I assume that what I am looking at around the transducer is a round piece of 1/4" plywood, a doughnut actually, which is a backing block. But the transducer appears to be threaded into it. Now maybe the plywood has swelled a bit from moisture and that's why it is such a tight fit. But in any event, it seems as good as threaded now. Right?

I was planning to drill through the transducer and then rig up a puller with a threaded rod and some blocks of wood, etc. But the more I look at this, the more I am doubtful that I can pull the transducer out, because of the way the threads contact the plywood.

Is my only option to figure that I need to first pry up the plywood doughnut, thread it off (if I do not destroy it), then try to pull the transducer from the outside? (It has a flange on the outside, so it has to be removed from outside.)

Or does anyone have an alternate approach? I have never tackled something like this before.

Any suggestions would be most appreciated.

Dean

mike ritenour · Post by **mike ritenour** » Mar 15th, '11, 18:15

Dean,
When I removed mine I just cut the whole thing out, making sure I left the block and previous hole in tact.
I used my trusty Dremel, although I burnt that one out also!
Good ole Dremel! Great tool.
Rit

Steve Laume · Post by **Steve Laume** » Mar 15th, '11, 18:16

It might not be a bad idea to replace that plywood backing plate so I wouldn't worry too much about destroying it.

What has most likely got the greatest hold on your transducer is whatever sealant was used. As the wire is clipped, it also looks like you don't plan to save the transducer.

I would chisel the backing plate away and then put some heat to the threaded area. That should be enough to loosen the sealant. You could then put a pair of channel locks on it and give it a twist. That should break it free and then you could pull or tap it out.

The drilling and puller sounds like a lot of work and still might not break it free, Steve.

gpb102030 · Post by **gpb102030** » Mar 15th, '11, 19:11

I removed both of my transducers and glassed in the holes i intend to shoot thru the hull with a puck transducer. To remove I just stood on them to get them moving a little rocking just ease your weight on them once the sealant looses its grip go under and remove by hand. pretty easy. Less stressful if the boat is on land but i did one once in the water to. Greg

M. R. Bober · Post by **M. R. Bober** » Mar 15th, '11, 19:48

Dean two thoughts: 1) try using Anti-Bond 2015 it will 'break" the seal of 5200 and such. Be sure to remove all traces of the Anti-Bond before bedding your replacement x-ducer, or 2) the guy in the yard who replaced my x-ducer gave it a whack with a mallet, which shattered the unit w/o damaging the surrounding area.

Good luck,
Mitchell Bober
Sunny Lancaster, (where someone bent on his genny today) VA

Phil Shedd · Post by **Phil Shedd** » Mar 15th, '11, 20:09

Dean

When I replaced my transducer it was a through hull type. I did what you seem to have done so far. Removed the nut and cut the cable. I could not move the unit so I did the following. I took a block of hardwood and put it on the top of the transducer. I hit that sucker with a large hammer. This broke the 5200 bond and with a few more hits the unit fell out.

When I replaced it I used 4200 to seal the shaft and the bottom of the unit . I used a lot of compound then tightened the nut . Works well and never leaked .

Hope this helps

Phil

Steve Laume · Post by **Steve Laume** » Mar 15th, '11, 20:25

I did this last year and glassed in the hole. I built up the hull and a fat spot inside. Then bonded the transducer to the inside. I am still claiming 2 knots of increased speed after getting rid of that huge fairing block. (Sailors might lie sometimes.) Also one less hole in the boat and I will never have to mess around with a transducer though hull again, Steve.

David van den Burgh · Post by **David van den Burgh** » Mar 15th, '11, 20:46

Before whacking it, you might jam two nuts together and then unscrew the thru-hull to break the sealant bond. Once it's loose, you could coax it out with some pressure or raps with a mallet.

Dean Abramson · Post by **Dean Abramson** » Mar 15th, '11, 20:59

then put some heat to the threaded area

Steve, are we talking hair dryer or blow torch? (I own the first.)

I will probably use both heat and Anti-Bond before proceeding.

These are all great suggestions. Thanks!

I think I am inclined to try the twisting route before I head down the blunt-force-trauma trail. I am afraid of cracking the hull. Nah, you say? I would be the guy to do this; trust me.

Dean

gates_cliff · Post by **gates_cliff** » Mar 16th, '11, 08:00

Dean, had to laugh at your last post! I'm right there with you.

What are you replacing it with?

On the other hand I'm intrigued with the idea of removing the external transducer and using an internal one. I've done quite a bit of fiberglass work and feel comfortable doing that work. But....I don'tknow if I have the time to get it done this spring and I need to get it done this year.

Steve Laume · Post by **Steve Laume** » Mar 16th, '11, 09:24

I don't think a hair dryer would do much convincing.

One of those little propane torches would definitely do the job. If you do buy one get the kind with the spark ignition. It makes things much easier, especially when it goes out in an awkward spot.

The anti bond might be okay to use around the backing plate if you are going to save it. My experience with the stuff has been lack luster. It seems very slow and not very good at penetrating into the far reaches.

Heating or warming the metal part will loosen the bond everywhere. You could fabricate a little shield to protect the wood and glass or just be careful to apply the heat in a direction in which it will not contact them.

You can also use that torch to break rusted fasteners and the unignited gas to fill opened paint and varnish cans so they do not form a film, Steve,

Jim Davis · Post by **Jim Davis** » Mar 16th, '11, 10:45

Not knowing how much swinging room you have, but you might try a galvanized pipe cap from the local hardware store. Then use a pipe wrench and torque the hell out of it. You should be able to break it loose. Heat gun in the outside will help.

As a last resort, drill all the way through (biggest hole you can make) and cut the body into segments with a saber saw or sawsall.

Len · Post by **Len** » Mar 16th, '11, 14:50

Dean,

Blunt force is your very last recourse !

PB Blaster seperates almost any struck piece of hardware (even whisker poles!)

Gently warming the pipe will loosen the sealant.

If the treaded pipe is no longer needed a hefty plumbers pipe wrench will remove it if you have enough elbow room.

You will replace the old plywood with a new hardwood block You could chisel out the old block

If you can drill a center hole of about 1/2 I have a slide hammer you could use. You stand outside the boat insert one end into you metal tube and using shoulder muscles etc you slam the weight to the extended end of the slide. This method removes VERY stubborn parts. I'll even donate my shoulder !

Lenny

Dean Abramson · Post by **Dean Abramson** » Mar 16th, '11, 15:59

Cliff, I am going to get a new thru-hull transducer from Airmar which will fit in the hole exactly. Theoretically. This is one reason that I want to be as careful as I can be. I don't (yet) do glass work.

Lenny, glad to hear the whisker pole loosened up! I'm going to attack this job tomorrow, if you want to come watch/help/BS. You can bring that Shock and Awe Device you describe, but it sounds like a method of last resort, no? I have De-Bond, newly-purchased heat gun, big honkin ChanneLock pliers, threaded rod etc., plus coffee and beer. Let me know. And any chance you have a little chunk of marine plywood or hardwood? :-)

If I decide to chisel out the backing block first, I will probably then try the threaded rod puller method, as that would put me outside the boat, with less chance of collateral damage to vessel and skipper. The space inside is pretty tight. It was already a living hell getting the nut off. Here is a wider view:

[img]http://www.mainephoto.com/folios/BoatDpthTrnsdcr-1.jpg[/img]

This area is accessed only thru the little aft-facing door under the galley sink. My head has to be somewhat under the shelf in there, which in turn puts my back against the engine cover, while the rest of the body has to make a U with my feet going forward. Or something.

I am really looking forward to it!

Marc Theriault · Post by **Marc Theriault** » Mar 16th, '11, 18:09

If you don't re-use the unit. The easiest way is to use a grinder and grind the device by the outside of the hull. Work slowly with a grind disk, touch only the unit until most of the material is gone and for remove it you just punch the unit in the boat. Protect yours eyes with google.

Anyway if you want to glass the hull you will need to grind a bevel in the fiberglass around the perimeter of the hole.

Good luck

Marc

The Cape Dory Board

Transducer Removal Help Needed

Transducer Removal Help Needed

pulling transducer out

removal

Heat

Pipe cap

Removal thougts