Depth transducer location

[Bigjim]

That's interesting. The box and the label attached to it all say that it is a P319. Someone is trying to pull a fast one, or they are hopelessly disorganized at Raymarine.

[JimsCAL]

The 30 year old Datamarine depth system on by Cal 33 stopped working a few years ago. Diagnosed it as a bad transducer. I bought a refurbished Norcross Hawkeye system with a transom mount/glue-in transducer (cost $70). Epoxied the Hawkeye transducer to the hull near the old Datamarine thru-hull transducer and spliced it into the old Datamarine wiring. Was able to get reliable readings up to 200 ft. Note that Norcross uses 200 kHz Airmar transducers which are compatible with many older depth systems.

[Bigjim]

I have epoxied the PVC pipe to the bottom. I should be able to install the transducer this weekend.

[KeelMe]

Originally Posted by Bigjim

That's interesting. The box and the label attached to it all say that it is a P319. Someone is trying to pull a fast one, or they are hopelessly disorganized at Raymarine.

Well, my Raymarine buddy finally got back to me and said it was a P319. But I called my buddy at JK Navigation, who has three on the shelf, and he says it is most certainly a P19. And I know I have installed a few and they have been P19. This Raymarine webpage says they are P19. And this Defender webpage says it's a P19.

Who knows what's going on...

[Bigjim]

I'm telling you that all the labels on the transducer say it's a P319. But you are right, the model number says it's only a P19. Sounds fishy to me.

[SVTatia]

Originally Posted by Bigjim

I have epoxied the PVC pipe to the bottom. I should be able to install the transducer this weekend.

Reviving the post to follow up on Bigjim's installation and performance.

I am about to do the same with the same M78713-PZ transducer, with RM's i50.

I'll appreciate the feedback.
Thanks in advance.

[SVTatia]

Originally Posted by SVTatia

Reviving the post to follow up on Bigjim's installation and performance.

I am about to do the same with the same M78713-PZ transducer, with RM's i50.

I'll appreciate the feedback.
Thanks in advance.

Bump to find Bgjim...

[bclaude]

We have a sailing boat with 9ft (2.7m) draft. Our rudder sticks out about 7ft (2.2m). We have begun to sail the Aegean sea which often requires to anchor with a line ashore or «*med style*» mooring to a public dock. As all sailboats, my depth transducer is located ahead of the keel which is of little use as we are backing towards the shore in rapidly decreasing water depth. Yesterday we tied to a city dock and had 2m (6ft) of water under the keel but only 30cm (1ft) under the rudder which is a bit close for comfort. This led me to consider installing a 2nd depth transducer aft of near the rudder with an alarm when it gets too tight. I am considering an in hull transducer since I only need shallow water info from that additional transducer. Conceptually I would epoxy a PVC tube to the hull to be filled with oil with the transducer installed in a screw on PVC cap as others have suggested above.

Two questions for this forum:

1. Has anyone done this before, what are the lessons learned? If I install right aft of the rudder is it a problem if the sounder can «*see*» the rudder in its beam. Since I am going backwards when I need the readings, I am not too concerned about the turbulences caused by the rudder or the prop. If space turns out to be an issue can I install near the skeg (axis of the rudder) in which case the lateral view would be obstructed by the rudder but not the aft view which I am concerned about.
2. My boat is equipped with Raymarine gear connected to a RayNet network. My two transducers would be far apart so I am not concerned about interference but I am not sure if and how I could quickly and conveniently switch back and forth between the two transducers as required or better have both measurements available to my instruments. I could install a dedicated display for the aft transducer by the helm if necessary but would rather not deal the hassle of pulling cables to the helm.

Your thoughts and suggestions are welcome.

[JimsCAL]

Two comments.
1. You would need to switch the transducers as I suspect the signal returns might interfere with one another. One way to avoid interference might be to use transducers with different frequencies.
2. Is your hull cored? If so you can't install it on the inside.

[Pete7]

We have the Raymarine ST60 forward of the mast, but a little Garmin Chart plotter with the sounder transducer glued in and firing though the hull of the cockpit locker. Really good picture so you don't need to drill more holes. The Airmar transducers for older RM and Garmin can be adjusted to take account of the hull angle.

There is a difference in frequencies and I am struggling to remember them, but I think the ST60 is 200Hz and the Garmin set to 50Hz as its dual frequency unit. No problem with interference. I do plan to replace the Garmin when it fails, now 16 years old, with a RM Element which is 235Hz.

However, in the past we have often rafted up to other vessels and haven't noticed ever having a problem.

Pete

[Kettlewell]

My boat came with an old Datamarine depthsounder with its transducer mounted pretty far aft, though ahead of the rudder. I installed a new Raymarine fishfinder with a through-hull transducer forward of the keel, so now I have depth readings from both sides of the deep keel. I have found it very helpful in certain situations. For example, if in a narrow waterway I can tell if I am trending toward deeper water by the differences in readings, and the fishfinder readout provides the slope of the bottom in some cases. I frequently anchor right on the edge of a dredged basin, and the aft depthsounder lets me know if I have ended up too close to the edge of deeper water.

[bclaude]

Originally Posted by JimsCAL

Two comments.
1. You would need to switch the transducers as I suspect the signal returns might interfere with one another. One way to avoid interference might be to use transducers with different frequencies.
2. Is your hull cored? If so you can't install it on the inside.

Thank you, good point.

I should have mentioned that our Hull is NOT cored in the lazarette which is where we would locate the transducer.

[capt jgw]

Most any transfucer without a speed wheel can be installed as a shoot through whether it's labeled that way or not. I've done it several times. The easiest way is to simply glue it to the inside of the hull being careful not to have any air bubbles in the glue. Epoxy is usually recommended but if you do that you'll never be able to remove the ducer without destroying it. I use clear silicone, works just as well and is removable. To find a good spot fill a ziplock bag with water, plop out down in the hull and press the ducer into that while a helper watches the display. Not all spots in the hull will work.

[chris mac]

2 ways to run a second depth with both displays always live are to
run a dedicated transducer to a display. Do not tie it into your network. That way both display at once and don't interfere with each other.
The other way , which I did. To display depth of each hull of our catamaran. Is to use a chart plotter that will display a fish finder/sonar. It's tied into the network but you can display it seperate to the raymarine depth sounder.
There are also wireless fishfinders designed to tow or cast on fishing line. They display to a device(tablet) with an app. We have one for the dingy, but for limited use one of these might do the job as well

[Donnybrook]

I have both a through-hull Raymarine 3 in one transducer and a Garmin in-hull (GT8HW-IH) and both work well on my Catalina 34 in Lake Michigan. I've seen depth and bottom from the sonar in over 100 ft of water.

Based on my experience, I'd go with the in-hull if I didn't already have a hole. I added the Garmin in-hull to take advantage of the sonar capabilities of my chartplotter.

It's best to have it in front of the keel. Behind the keel you're looking at depth history, but in practicality the difference is only a couple of seconds.