Transducer Replacement - Part Number and Pricing

I need to replace the transducer in my 2008 SR 290 Sundancer. Does anyone know the part number or a good place to purchase. My local service center has one for $360. Is that a reasonable price or should I check on line?

Thanks in advance.

Ralph

Ralph vaughn said:

I need to replace the transducer in my 2008 SR 290 Sundancer. Does anyone know the part number or a good place to purchase. My local service center has one for $360. Is that a reasonable price or should I check on line?

Thanks in advance.

Ralph

Click to expand...

Yes, no, maybe, it depends. In all seriousness, without knowing the capability of the transducer and equipment you have and what you are buying there is no way of telling. For a single frequency depth only it’s high, for dual frequency depth, temp & speed with fairing it’s reasonable. I just paid about the same for a transducer matching the latter plus $1k more for installation in a cored hull.

Thanks Henry. I think mine is dual frequency, depth and temp. My understanding is that the speed is determined by the GPS, not entirely sure this is true. Is replacing the transducer a difficult job?

Ralph vaughn said:

Thanks Henry. I think mine is dual frequency, depth and temp. My understanding is that the speed is determined by the GPS, not entirely sure this is true. Is replacing the transducer a difficult job?

Click to expand...

If SR put it in the same place as in our 280 it will be under the starboard engine. I’d recommend thinking about having it done. Unless you decide to leave the existing in place and have an accessible spot, DIY can be a big PITA.

Ralph vaughn said:

Thanks Henry. I think mine is dual frequency, depth and temp. My understanding is that the speed is determined by the GPS, not entirely sure this is true. Is replacing the transducer a difficult job?

Click to expand...

Henry Boyd said:

If SR put it in the same place as in our 280 it will be under the starboard engine. I’d recommend thinking about having it done. Unless you decide to leave the existing in place and have an accessible spot, DIY can be a big PITA.

Click to expand...

mine is in the center of the bilge between the two engines and all the way forward in the bilge. Not too hard to get to but still a DIY challenge. I will probably have it done

Another question does my transducer also control my speedometer?

Thanks Ralph

In your case with a 290 w/B3, speed can come from: gps SOG signal, B3 pitot pickup, and/or depth transducer. There are other speed sensing devices, but are used with shaft or outboard driven vessels.

Traditionally the pitot method has been the mfr choice. Your boat most likely has Smartcraft. If your depth data comes via Smartcraft, then most likely there is a pitot tube that measures speed by measuring the water pressure exerted on the sterndrive as the boat moves through the water. The B3 has a hole drilled in the leading edge that water flows into. (Originally this water line was plumbed all the way to the helm and the Speedo was simply a diagram pressure gauge.). With Smartcraft, a pressure sensing device at the transom has the hose plugged into it, and that converts water pressure into a digital signal that is sent to an electronic Smartcraft speedometer. This produces Speed Through Water (STW), or the speed of the water moving under the boat.

Speed from the gps can be introduced to a Smartcraft system by connecting a third party gps to the Smartcraft system. This gives Speed Over Ground (SOG), or the speed of the vessel relative to a fixed object on the shore.

There is a whole discussion of the advantages and disadvantages of SOG vs STW I’ll leave to you to research. SOG is generally more beneficial for navigation, and STW more useful for radar collision avoidance calculations. In both cases, a modern mfd will be doing those calculations so the only practical uses of STW is for fishing or pulling a water skier.

Gemeco in SC.. they own airmar.. they are very helpful

Thanks everyone for all the good information.
Ralph

Hey Ralph. My 2008 290 has the smartcraft transducer tied into the smartcraft. It measures depth and temp through the smartcraft gauges. The pitot tube is a different system for speed. The transducer has a label tag on the wire near the transducer. A bit hard to get down there to read it, but mine is something like this:

MerCruiser 888828-1
AIRMAR P17 (P/N: 44-031-3-01)

No guarantees but googling it looks like it superceeded by this part number:
79-8M0122505 which seems to go for around that price of $350.

If the boat is out of the water, it's very easy to get out to replace. Mine was a bit more difficult as I had to hit it softly with a mallet outside of boat because it had a little salt holding it in the housing. Theoritically it's supposed to be capable of changing even in the water using the plug, but I would recommend that if you dont know the transducer will easily come out of the housing. BTW my housing was leaking slightly. I just took it out and planning to re-seal it, although now I'm thinking of going to a Raymarine transducer to be compatible with Axiom MFD.

May I ask why you need to replace the transducer?

Riptide III. My depth finder was working intermittently and finally stopped working. Not sure if my temperature also stopped.

Ralph vaughn said:

Riptide III. My depth finder was working intermittently and finally stopped working. Not sure if my temperature also stopped.

Click to expand...

That pretty much sums up why we got a new one as well this year.