8 posts / 0 new
Last post
Last seen: 2 weeks 5 days ago
Joined: 7/27/12
Posts: 226
Depth Transducer

My boat has a Raymarine B117 installed.  My depth has been flakey in operation with both a DSM300 and my current E127.  This tends to occur in shallow water the most and my suspicion is that this is the wrong transducer.

The B117 is mounted next to the speed transducer under the vberth drawers and can support a 0-7 degree deadrise.  

I am curious to know what others have installed in this location as its bottom job time and I'm going to replace it.


2000 C36 MKII 1825


2000 C36 MKII 1825

Haro's picture
Last seen: 1 hour 25 min ago
Joined: 11/7/14
Posts: 154

My depth transducer also is not dependable. Intermittently and in shallow ( about 9 feet ) if water - you may see it shoes 3 dashes. The only way to restore is to turn off the power and back on on the instruments. It sometimes displays the heading instead of the depth. When I bought the boat I found an old depth transducer in the drawer. This means that someone had replaced the depth transducer - probably for the same reason. That has not solved the problem. I believe this is a technical problem since all the data is transmitted in a serial format on the same bus, the instrument displays become confused as to which data is for a specific display. Does anyone have a solution?

Sail La Vie 1999 Catalina 36 MKII, M35B, Coyote Point, San Mateo
bakerha's picture
Last seen: 3 hours 49 min ago
Joined: 7/23/10
Posts: 173

My 89 Catalina was equiped with Signet electronics when I bought her 9 years ago. The depth was horrible in shallow water (kind of where you need it most).  They recommended replacing the transducer - which I did - and that did not help.
So I bit the bullet and installed new electronics (Garmin) and an Airmar B60 - 12 degree tilt  transducer.  Now the depth is rock solid even in shallow soft bottom areas.
My transducer is mounted under the forward cabin floor just to Starboard of the keel line.  I used a cheap angle gauge from Menards to check the dead rise there and it was right at 12 degrees.


Harold Baker
S/V Lucky Duck
Sandusky Ohio, Great Lakes
1989 C-36 mkI TR/WK M25XP

True Wind
Last seen: 2 weeks 4 days ago
Joined: 7/15/12
Posts: 40

The e127 unit has built-in sonar. It has ClearPulse with 50/83/200 kHz operating frequencies up to 600W RMS plus a sonar transducer port. Interesting a DSM300 was inserted when it's not needed. 

I would start with the DSM300. This unit is voltage sensitive. Make sure your voltage is good at the DSM. If that looks good ,then the next time you lose bottom depth or are not getting a good solid return, check the status LED on the DSM300. See page 62 and 63 on Status LED in the attached DSM300 manual.  

My 2002 C36 has about a 17 degree dead rise. If yours is similar to mine then even if it were working correctly, you are shooting off dead center unless there was a fairing installed to off set the dead rise. I would also use the 200 khz frequency as this is better in shallow water.

I forgot something. Make sure you are not using clear pulse or 83 khz. The B117 is only good with 50/200 khz.

PDF icon dsm300.pdf1.63 MB
Last seen: 2 weeks 5 days ago
Joined: 7/27/12
Posts: 226

Wow!  Awesome replies.  :)

i attached the B117 directly to the E127.  The DSM300 is sitting in my office.

it does not appear to be faired at all and I suspect this is the trouble (shooting off center).  As noted, it tends to crap out when I really need it.  I'm going to toss in a B60 (e127) and will replace the speed transducer with a DST800 triducer (ITC5) when I get my bottom done.

let you know the results.


2000 C36 MKII 1825

True Wind
Last seen: 2 weeks 4 days ago
Joined: 7/15/12
Posts: 40

The DST800 tri-ducer comes in three versions, analog, 0183 and NMEA 2000 (Smart™—NMEA2000®). They only come on 0 dgree tilt. I would suggest that you go with the NMEA 2000 version and bypass wiring the analog version into the iTC5 analog transducer connector. Assuming you have a SeaTalkng network setup already, there is a SeaTalkng spur port on the outside of the iTC5 that you can attach the DST800 NMEA 2000 version to, unless you have used that open spur port. If you use the spur port, you will also need a DeviceNet adaptor cable which Adapts SeaTalkng to NMEA2000 network. Available with Male or Female ends. If you use the NMEA 2000 version you just insert it into the SeaTalkng network. 

There is a DT800 Smart transducer that come in Low-Profile 0° Tilt, Low-Profile 12° Tilt and Low-Profile 20° Tilt. They come in plastic, bronze or stainless housing. This may be the cats meow for you.

This is my two cents worth.

rjwilson's picture
Last seen: 1 hour 16 min ago
Joined: 4/28/14
Posts: 29

I had the same issue with my transducer last year and the cause was a simple one. I had put too many coats of bottom paint on it. Before replacing it you may want to remove any excessive bottom paint. That worked for me and I haven’t had any issues sense then.    

Bob Wilson
S/V Morning Breeze
2003 Catalina 36, Hull 2122
Williamsburg, VA
LeslieTroyer's picture
Last seen: 21 hours 43 min ago
Joined: 3/13/16
Posts: 261

I have the dst800 thru an ITC5 under the vbirth. Next to it is an abandoned shoot thru hull.  I also have a Furno under the galley sink.  Both work well in shallow water but the DST looses the bottom at about. 300 feet. 

Les & Trish Troyer
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 
Log in or register to post comments