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Remember you're a womble
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Discussion Starter · #1 ·
So, it seems that the DSI transducer is somewhat sensitive to placement, many suggest that it will only work when in direct contact with the water (i.e. transom mounted) and Lowrance reckon the performance is significantly degraded.
I found one spot in-hull where it seems to pick up a depth reading, the problem is it's about 8-10" in front of the furthest forward keelbolt and therefore I assume it is still actually shooting through the keel itself. Is this going to be a terrible place for it when underway?
The alternative is to just return the whole unit and get a non-DSI version.
Thoughts?
 

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Forward on the center line is the best location as long as it is not over the keel. Move it around fore and aft and if you get a depth reading you are not still over the keel.
 

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Remember you're a womble
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Discussion Starter · #3 ·
The location that seems to works is basically just aft of the mast compression post, which according to the line drawing is still very much keel, clicky
 

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If it is aft of the compression post it is certainly over the keel. What about under the aft part of the V-berth? If that works it would be good. Check the depth over the side and compare with the inside reading.
 

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V berth location works great

I mounted my d s I transducer by bonding with epoxy in the aft vberth area and find that it works better than expected. While I don't have water temperature, I showed depths within a foot or so of the chart for a given area.

Murphy
SV Amalia
1965 Cal 30
Muskegon, MI
 

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Remember you're a womble
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Discussion Starter · #6 ·
I tried in the compartment where the existing through-hulls are located, I tried in the hanging locker, I tried in the locker under the sink in the head, I tried in the locker under the rear of the v-berth. The only place I could get a consistent reading was right at the base of the compression post. Hopefully that doesn't mean it's in direct contact with the water :D
I'm going to temporarily install in that location in the morning and go for a bit of a pootle around and see what it reads like when under way. If it appears to work then I guess it will work, if not then back it goes.
 

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Remember you're a womble
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Discussion Starter · #8 ·
Nope, solid hull. I think these DSI transducers are stupidly picky. I'm kinda tempted to just box up the whole thing and take it back, but it's a nice unit and since they appear to be discontinued, I suspect the replacement will be a touchscreen abomination.
 

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Nope, solid hull. I think these DSI transducers are stupidly picky. I'm kinda tempted to just box up the whole thing and take it back, but it's a nice unit and since they appear to be discontinued, I suspect the replacement will be a touchscreen abomination.
I have had good success installing a handful of transducers with epoxy inside hulls. One was a bit finicky but it was a transducer on a $99 West Marine depth sounder bought on clearance by the customer. My own is a Raymarine ST-40 with Airmar transducer and worked well in several locations. I epoxied it to the hull under the aft end of the V-berth in 2 stages. First I leveled the area with epoxy dammed in place with butyl. Next day I used epoxy to install the actual transducer in place. I picked the Raymarine as the numbers are very legible from a distance. Easy to see from the aft end of the cockpit. Most of the other depth sounders I have seen have too small of a number display.




All I wanted is depth as I have a separate plotter.
 

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Discussion Starter · #10 ·
I tried the baggy of water, toilet wax and building a little dam and pouring water in. None of them worked in any of the locations.
The little Lowrance allows me to have an overlay of depth, about 1" high which is plenty visible. The alternative is to just get something like the ST40 I guess.
 

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Discussion Starter · #11 ·
Tried the location by the compression post. Fine at the slip, not good underway. Will be returning to exchange for a non-DSI model.
 

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I was able to wire up a 25 year old Signet depth transducer to a 'new' Raymarine ST 40 head - works great and I gained over 100 feet of reading over the old Signet.

Do you still have an old transducer in the boat?
 

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I was able to wire up a 25 year old Signet depth transducer to a 'new' Raymarine ST 40 head - works great and I gained over 100 feet of reading over the old Signet.

Do you still have an old transducer in the boat?
That is what I've done on my boat as well. I have ~20 year old "Autohelm" (quotes because they were made by Airmar, just like most transducers) transducers talking to my Raymarine e7D head.

The depth transducer was easy to get going. The speed transducer worked incorrectly for the e7D, but I bought a ST70 speed transducer to SeatalkNG head cheaply (used, about $70) and used that to get boat speed working. Temp doesn't work, though it appears to be wired correctly. I don't really care that much about temp.

Airmar publishes wiring diagrams for every transducer that they've made, including the pinouts to the manufacturer's plug. Airmar's website makes them hard to find, but this one makes it a lot easier:
Marine Technology | Blue Heron Marine expertadvice

Click on "Wiring Diagrams", then find your model. Lowrance wiring is here:
http://server.iad.liveperson.net/hc...41278/!DOWNLOAD?entryid=404300&attachid=40330

Airmar uses standardized wiring colors. Blue/black is depth.

Almost all of the marine electronics connectors that I've seen are made by Conxall. In the US you can get the bare connectors from Mouser or Digikey.
 

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Remember you're a womble
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Discussion Starter · #14 ·
There's an old transducer already in there, I was going to wire that up to my existing Northstar head unit but that has been messing around so much recently that I figured I would just replace it all. To bring the existing transducer wiring to the new location is going to involve so much work, pulling it back through, splicing in lengths of cable etc so I might as well just put a brand new one in.
 
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