Airmar 2 inch thru-hulls: brand-agnostic?

[LongRange]

Can I drop a B&G DST800 transducer into the Airmar thru-hull left behind by a (removed)
Airmar ST 20-399-01, Raymarine OEM part E26031?

Or to put it another way, can I remove my existing Raymarine ST800 as if I was just going to clean its little paddlewheel, while the boat is in the water, and instead of it put back a B&G (Airmar) DST800 into the same hole in my hull?

The Raymarine ST60 instruments have stopped working, and I am loathe to invest in replacements for what is now older technology. Given I also have a B&G Zeus3, which is pure awesome, ideally I would like to replace the Raymarine transducer with the B&G DST800 - as long as I don't have to haul the boat out of the water to replace the through-hull.

To clarify, I totally understand that the transducers themselves are (usually) brand-specific, and I am not looking to plug an old transducer into a new instrument, or anything like that.

I would just like to re-use the plastic thru-hull that seems like the ubiquitous Airmar 2" size for a completely new transducer plugged into a completely new MFD. Is that doable?

Thanks for all advice!

[LongRange]

I will ask the question a different way...

Should I be able to drop any Airmar transducer designed for a 2" through-hull into a plastic P17 that has been sitting in my hull for over a decade?

(I get the feeling that these "P17" through-hulls are ubiquitous, and that there is no need to swap the actual through-hull just because a new transducer has been bought, but I am not sure.)


Also, what does the "DST 800 P120" nomenclature mean? I understand that 'DST' is Depth, Speed, and Temperature, but what about the '800' and the '120'?

Thanks.

[skipmac]

Not sure if all same size transducer are exactly compatible in the installation but I was able to replace both of my ancient Datamarine transducers twice, keeping the same through hulls, threaded ends, etc.

The second swap was to a Raymarine ST40 system that I'm still using so I know at least some Raymarine is exactly the same physically as some other models.

[Outlaw7]

They are the same transducer and both NMEA compliant. For verification call Gemeco at 1 803 693 0777. They are the Maretron people!

[LongRange]

I found out the hard way that the answer to the original question is "NO".

Although the outside 2" thread of the newly-purchased Airmar "Navico" DST800 is the same diameter as the old Raymarine ST800, the internal sleeve of the old ST800 is narrower than the body of the new DST800.

In other words, if the ST800 is removed from the through-hull, the DST800 is too wide to fit in its place. Only a few millimetres difference, but it might as well be a metre.

So now I will have to get the boat lifted out, and the new transducer installed with its own (internally wider) through-hull. Lesson learned, and I hope this is useful to others considering the same swap. No doubt there are combinations that are compatible/swappable, but just because it's an Airmar through-hull with a 2" outside diameter does NOT mean it will take other Airmar transducers that also come packaged with a 2" through-hull.

Thanks to everyone who responded. Much appreciated.

[Mr B]

Dont you just love, Inbuilt Obsolesence,
I got a new depth sounder but with out the screwed collar,
The collar I have wont go on the new one, My one has a lip on it,
At least you have the numbers for yours, I dont,

[Outlaw7]

I take it you did not call Gemeco?

[LongRange]

Originally Posted by Outlaw7

I take it you did not call Gemeco?

No, I did not. I have never purchased anything from Gemeco, and I am very unlikely to do so in the future, given the boat is in the Med. Under those circumstances I did not want to seek favours or waste their business time.

It's all good. The new transducer was getting installed anyway, eventually, so the only thing I lost was the gamble that it could be done without pulling the boat out.

Thanks again.

[LongRange]

Also, it occurred to me that had the new transducer body been slimmer than the old one, it would probably fit into the internal sleeve of the through-hull, and be deprived of support it needs down on the lower end where it exits the hull. All the stress would have been on the top of the plastic thread of the through-hull, and that could easily lead to cracking.

Another crisis averted

[FlyingScot]

I wish I would have read this earlier. I just tried dropping in a new DST Airmar into the housing of the old 20-399-01 and same as you, I found the new model to be thicker than the old model. I ran the wire with some trouble, and split my head open during the cleanup process. Not a good day

[meridian28]

If it is just a bit of clearance could you use a brake cylinder hone or is there not enough thickness?

[FlyingScot]

Originally Posted by meridian28

If it is just a bit of clearance could you use a brake cylinder hone or is there not enough thickness?

Mine is all plastic.