Sonar... again

[Cutwater28GG]

I know there are a ton of threads on this which I have read but wanted to check for any new thoughts.

I have a glued on p79 airmar. Garmin 5212. No glycol cup.

Sonar has worked reasonably well up until now. Not great detail but pretty good bottom holding.
(Ok for 3 years. Occasional would have drop outs. )
This weekend was a little choppy and the boat banged into a few waves. - nothing crazy.

Sonar stopped working at some point in the trip. I didn’t notice the exact moment. Do not know if banging was the cause. Now it shows typical surface detail as it hunts for the bottom in full auto for all settings. It never finds bottom. Just largely a blue screen. With the occasional color pixel at a random location.
I’ve tried messing with manual settings such as gain to try and force it to see the bottom again. No bottom detail ever surfaces.

I am sitting in the marina at low tide - I’d guess about 12 of water below me and I can see the bottom. Sonar can’t find a damn thing.

Checked the transducer and it’s still glued down well.

Some questions.

1. Where does the sonar cable run to? I assume it’s hard wired to the garmin rather than nmea network. But I don’t see that cable on the back of the 5212? I want to check the connections
2. Can a transducer go bad?
3. Any recommended settings on the sonar to troubleshoot?
4. Is the only way to reset a transducer to turn off the house power?
5. Other ideas?

 

[Cutwater28GG]

Ok if I set gain to 100%. Depth to 30feet. Noise reject off. No zoom
No surface noise

I get a very intermittent response from the bottom but it’s not enough to lock a depth (flashing) at 15ft

With gain at 100% shouldn’t I be getting all sorts of noise from the water? It’s As if the transducer has very poor reception currently?

 

[knotflying]

Well, as much as you may hate to, I think I would reinstall the transducer with the cup and fluid. However, before you go there I would disconnect all the cables from the box behind the helm and then reconnect them. This will totally reset the unit. See if that works.

 

[Andrew Custis]

Always make sure zoom is set to auto. You should really never change this. If you do and go in deeper water than the current set zoom, it will drop out. On the 5212, you have what’s called a GSD22 which is a remote sonar box. I believe this is mounted either behind the plotter or below the helm throttle control which is accessible from the mid cabin. You might consider buying another P79 and using that for your testing and then you’ll have a spare in case yours really does go bad.

Thank you,

 

[Cutwater28GG]

Screen is just blue when set to auto. Just surface noise in 18 feet of water

Found the gsd 22. Actually reasonably accessible once you unscrew the panel on the cutwater. I will try removing all the cables on the gsd 22 and reinsert them.

 

[Cutwater28GG]

talked with the factory (thanks guys!) and with Garmin. I have purchased a replacement transducer and will test this before installing to make sure the problem is not the GSD 22. (Garmin says you can send your GSD 22 in and they will send you a remanufactured one for $89 if its faulty!)

planning ahead for installing a new transducer; I have a few options.
1. remove the existing transducer (which was glued on and not installed with the glycol cup) and painfully clean up the hull and install in exactly the same location.
2. leave the existing install and install the new cup along side the old location (in the same general hull area next to the shower sump) on a clean area of glassfiber
3. find a whole new location for the transducer.

I think my preference is 2.
I think Brian (BBMarine) installed a through hull transducer in the engine bay of his cutwater 26. has anyone installed a in-hull transducer anywhere else in a cutwater 26/28 or R27?

I plan on using soap water and then isopropyl alcohol to clean the area - is this OK?
Do I need to sand the glassfiber? (Note the boat is in the water when I'm doing this)

Then use Marine tex quick set to glue on the cup (per the instructions from the marine installers rant blog)
https://www.amazon.com/gp/product/B000Y8A06C/ref=od_aui_detailpages00?ie=UTF8&psc=1
http://themarineinstallersrant.blogspot.com/2014/08/p79-transducer-install-and-repair.html

Any other glue type advice?

any other tips?
(the challenge of running a new cable is rather daunting as well on the cutwater as it goes up under the floor behind the water tank. which as far as I can tell is impossible to get to)

by the way anybody know what the deadrise of the cutwater 28 is at this location?

 

[ixlr8]

The folks at RT told me to use 3M 4200 and not to use epoxy to put my sonar cup back on. I have heard they used epoxy in the past, but they didn't tell me the reasons for not using epoxy now. The 4200 did not stick well to the cup and it came loose again. I did a better job of roughing up the surface of the cup and used 3M 5200 this time. 5200 has 3x the holding power of the 4200. 5200 is considered permanent, while the 4200 is considered removable. We haven't been out since I put the cup back in with the 5200 to see if it sticks. We plan on taking the boat out Sunday. Andrew told me they use the 4200 at the factory. I used Acetone to clean the surfaces as both of the 3M products say NOT to use alcohol as it will prevent the product from curing properly. The key to getting the cup to stick is to make sure the surface is well roughed up. It was recommended to use 80 grit sand paper, I used 36 grit as that is what was handy for me.

 

[rpmerrill]

I have the exact same problem. Posted yesterday "Depth sounder access on R-27" (2012 model also)

Andrew told me that my unit is totally glued in place. Solution is to replace it. After 6 years, I'm not too upset.
(I sure hope it is the transducer causing my problem !)
It really is in a tough location, but I can't see many other possible good spots.
I think remove and replace is my best option. (Not sure about the wiring routing???)

I'm going back this morning and will attempt to slide the holding tank about 6 inches forward to get better access to the current transceiver location and maybe trace the wiring?

My local boat electronics shop is sending a guy to look at my situation on Wednesday. If he has any other ideas, I will post them.

 

[rpmerrill]

Bad news, holding tank is not going to move.
Part of the tank is behind the muffler.

I got a good photo of the tight installation and I'll add it to my album. (Ya I saw the loose screw.)
I am now in the school that says just relocate it. I'm thinking engine compartment on the port side. I'll attach a photo of that as well.

Oh, here's a news flash.... I went for a 12 mile cruise this AM and all is well. Depth and sonar is working perfectly.
Go figure.

 

[Cutwater28GG]

I think I found my culprit. The glued on transducer glue has failed. There is a hairline crack in the glue and I can wiggle the transducer and the gap increases. Definitely seems to be a failure of the bonding.

Now the decision is whether to remove it and clean up that location for a new cup install or just put the cup the side of the old transducer.
The wire run seems like a right pain.

Looking at the hull in this location.
1. It looks sanded down for the install location - see the rectangle shape
2. It’s then painted over

Do I need to remove this paint before installing a new transducer?

 

[Cutwater28GG]

Anybody know the deadrise angle of a cutwater in the bow section?

 

[ixlr8]

I think I found my culprit. The glued on transducer glue has failed. There is a hairline crack in the glue and I can wiggle the transducer and the gap increases. Definitely seems to be a failure of the bonding.


Looking at the hull in this location.
1. It looks sanded down for the install location - see the rectangle shape
2. It’s then painted over

Do I need to remove this paint before installing a new transducer?

I suspect you will find that 'paint' is gel coat. At the very minimum it needs to be sanded to remove any remaining wax coating and roughed up to give a good bonding surface. Depending on what you are going to use for 'glue' you might need to sand it down to the glass.

 

[Cutwater28GG]

Making slow progress.

Nothing than quite like doing this sanding to the hull with the boat in the water! :shock:

 

[Cutwater28GG]

Question. If I’m using a cup with glycol do I need to get it smooth? Just as long as the cup adheres and is water tight right? The glycol will fill the gaps/unevenness no?

 

[Brian B]

When I did mine a few years ago I used an oscillating tool with a scraper blade to remove the old epoxy. I then got it as smooth as possible and installed a new cup that holds the glycol. No issues since I changed to the fluid cup.

 

[Cutwater28GG]

Posting for moral support.

Spent the last two hours pulling out panels trying to get to the cable run for the transducer. No luck. Firmly behind the water tank dropping into a void. Without serious dismantling it seems futile.
Factory confirmed that it was likely installed prior to interior assembly.
New boats have a different cable run as there is no gsd 22.

Three options.

1. Glue the cup in and use the old transducer. This will require careful peeling off the old 4200/5200 from the transducer face. Not sure how well that will go.
2. Glue the cup in and cut the cable on the old transducer and splice the new transducer onto the existing cable. Airmar do support this but you are supposed to use their junction box but I don’t think I have enough slack in the cable for their box. Good news is locations is dry. .
3. Throw money at the problem and get someone else in to figure it out!

I think tomorrow I will try things in this order unless others have ideas.

 

[Scotty Mac]

I had same problem on R31cb, I just roughed up surface enough for the silicon to bond and used the cup with fluid. Has worked great for the last 6 months. A lot more prep would be required if gluing back down as you can't have any air bubbles . The cup also makes getting the angle correct a lot easier then gluing back down. Just my .02

ScottyMac

 

[knotflying]

Posting for moral support.

Spent the last two hours pulling out panels trying to get to the cable run for the transducer. No luck. Firmly behind the water tank dropping into a void. Without serious dismantling it seems futile.
Factory confirmed that it was likely installed prior to interior assembly.
New boats have a different cable run as there is no gsd 22.

Three options.

but I don’t think I have enough slack in the cable for their box.

The new transducer should have plenty of wire. Can't you just put the junction box back far enough to get enough lead from the existing cable and just use whatever length you need from the new transducer? With that said, I would install the cup, clean the old transducer up and see how it works. I assume the cup is compatible with a new transducer if needed.

 

[BB marine]

I would first install the cup. Then clean up old transducer and install it in the cup with propylene glycol. If it works good great! If it is still not reading properly, I would then install a new transducer. Leave the old cable in the boat. Run the new cable ( cord ) to the helm. If your C28 is the Same as my C26 the removal of water tank bulk head, air unit bulkhead and port side cave bulkhead gives good access to run a cable from port side to starboard side. The hardest is getting the transducer cord from the bilge to the air unit location ( If you have a air unit) if you don't its even easier. there is a gap between the interior insole (liner) and hull to run the cable in between. I ran a TV cable, 12/3 boat cable and a 1/2" water line up thru there to the bow. It wasn't easy but it was achievable. I would not terminate the cable and install a new end.

 

[Cutwater28GG]

thank you, thank you. your counsel is appreciated! I will try using the old transducer first. will report back on progress even just for cathartic therapy!