DST vs DT Transducer Options

[unsalted]

I’m replacing a through hull depth transducer that has become unreliable. I’m looking to replace it with an NMEA transducer and adding temp and possibly speed as it seems like a good idea. I plan to feed the data into my Garmin MFD. The ultimate replacement would probably be an Airmar UDST810, so that I get depth/speed/temp wo/ the need of a paddle wheel (and the issues of the paddle wheel fouling over the season), but the price point is 2x+ the DST. My second thought was to drop speed and go with a DT800 to avoid the fouling issues but I wonder at the benefit of low-speed speed data provided by the paddle wheel over the GPS speed-over-ground provided by the MFD (speed doesn’t become accurate until running faster that 6 mph). Thoughts or suggestions?

DT = .3-4 Boat Bucks
DST = .4-.5 Boat Bucks
UDST = 1-1.1 Boat Bucks

Thanks all for your knowledge and experience in advance.

 

[Golfman25]

I don't think transducer speed is all that accurate as it can be influenced by current and such. So to me, not worth a whole lot extra.

 

[b_arrington]

Accuracy of through water speed at low speeds is most important for fishing. When fishing presenting the bait at the right speed is important, and will be affected by currents. Your gps may say 5 mph, but going with the current could be more like 2 mph. Therefore an in water speeds sensor makes sense.

To me that’s really the most compelling use case for DST. Maybe there’s an other one for sailing or slow trawling. But not for a fast planing boat like a Sea Ray.

I’m really surprised you don’t get good gps speed readings until 6 mph. Mine is accurate are much lower speeds. However a hearing sensor is nice for orienting the boat.

Certainly go with the DST if you want or do fishing, but I don’t think it’s worth it. If you do, go for the the ultrasonic. Having had several paddle wheel speed sensors I can confirm they foul easily and will eventually fail.

 

[dtfeld]

I have the DST in my boat, and it's pretty inaccurate, especially as the speed increases. Your GPS should be accurate to +/- a couple tenths of a knt/mph depending on the genetation of GPS. If GPS not working until 6 mph, something wrong or needs updating, maybe even a new GPS with a heading sensor would better $$

I have a hard time justifying more than about $20 for a new paddle wheel, just to keep it working.

The depth and temperature functions are very worthwhile IMHO. Use this all the time.

 

[quality time]

I had two DT800's fail on the temp side within two years. This was a fairly common problem but I believe they came out with a newer version that was supposed to fix this.

 

[Skybolt]

I had two DT800's fail on the temp side within two years. This was a fairly common problem but I believe they came out with a newer version that was supposed to fix this.

Yep, I went through a bunch even the newer hw rev 4 failed for me. I want to try the new 810 but am very skeptical to do so because of these other failures.

 

[Skybolt]

I don't think transducer speed is all that accurate as it can be influenced by current and such. So to me, not worth a whole lot extra.

Keep in mind that transducer speed is speed through the water and GPS is speed over ground. The two will almost never match and the difference will be the speed of the current for the most part.

I find the transducer speed to be useless in most cases and the GPS speed to be highly accurate, but it does lag if you don't have a fast updating GPS antenna. I idle at ~7mph depending on the current. So that throughs you off a bit.

 

[unsalted]

I’ve decided to go with the DT800 as in the end I’m not sure the speed issue is as much of an issue. I may be confusing my GFS speed issue with my GPS heading problem, which would ultimately be solved via a heading sensor. The other thing I discovered is the DST810 is not officially supported by my 24 degree dead-rise where the DT800 is. The DT800 is a retractable transducer so if I become forlorn about not having speed then at least I could buy the DST810 and plug-and-play. Thanks all for the input it was helpful in assisting me in making up my mind.

 

[Skybolt]

I’ve decided to go with the DT800 as in the end I’m not sure the speed issue is as much of an issue. I may be confusing my GFS speed issue with my GPS heading problem, which would ultimately be solved via a heading sensor. The other thing I discovered is the DST810 is not officially supported by my 24 degree dead-rise where the DT800 is. The DT800 is a retractable transducer so if I become forlorn about not having speed then at least I could buy the DST810 and plug-and-play. Thanks all for the input it was helpful in assisting me in making up my mind.

Be fore warned that the DST800 is completely untrustworthy after the first year. Various functions decide to not work. And the STW is useless as soon as there is any debris on the paddle wheel. In a week or two no speed. I think only the 810 would be worth trying.

I have had all four HW revisions and am very reluctant to try the 810 as a result. But good luck!

 

[unsalted]

I choose the DT800, which has no paddle wheel, just Depth/Temp. Not to be confused with the DST800, which has a paddle wheel and provides Depth/Speed/Temp. I thought the DST800, which was replaced by the DST810, did have reported issues with Temp sensor failing and the paddle wheel was also more susceptible to fouling than the DST810. The DST810 also provides heel and roll values, which are more important in calculating speed for sailboats.

My reasons for selecting the DT800 were:
1) I have no recent reports that I could find on quality issues
2) It doesn’t have a paddle wheel, so fouling should be reduced.
3) It’s good to a depth of 600ft, where the DST810 is good to 330ft.
4) With the 20 degree tilt model it supports a dead rise of 16 to 24 degrees vs the DST810’s 0 to 22 degrees (310 DA has a dead rise of 23 degrees).

 

[Skybolt]

I choose the DT800, which has no paddle wheel, just Depth/Temp. Not to be confused with the DST800, which has a paddle wheel and provides Depth/Speed/Temp. I thought the DST800, which was replaced by the DST810, did have reported issues with Temp sensor failing and the paddle wheel was also more susceptible to fouling than the DST810. The DST810 also provides heel and roll values, which are more important in calculating speed for sailboats.

My reasons for selecting the DT800 were:
1) I have no recent reports that I could find on quality issues
2) It doesn’t have a paddle wheel, so fouling should be reduced.
3) It’s good to a depth of 600ft, where the DST810 is good to 330ft.
4) With the 20 degree tilt model it supports a dead rise of 16 to 24 degrees vs the DST810’s 0 to 22 degrees (310 DA has a dead rise of 23 degrees).

My bad on the DT vs DST. But the failures your not going to find in reviews. But you will on this forum and also over at THT.

Trust me I wish it would work as advertised, but after 4 in 3 three years, two DOA out of the box. I am very reluctant to buy another. JMO.

 

[unsalted]

My bad on the DT vs DST. But the failures your not going to find in reviews. But you will on this forum and also over at THT.

No worries, I appreciate the input. I’m looking for an nmea 2K transducer so I can integrate it with my Garmin. Do you know of better choices? I’m not a fisher, so I purchased the 8612 wo/ sonar, so an nmea compatible transducer is my easiest integration choice.

 

[Skybolt]

No worries, I appreciate the input. I’m looking for an nmea 2K transducer so I can integrate it with my Garmin. Do you know of better choices? I’m not a fisher, so I purchased the 8612 wo/ sonar, so an nmea compatible transducer is my easiest integration choice.

No better choices, actually no other choices. I am the same way and on the fence about the 810 because of my past experience with the 800. It looks like they discontinued the 800 and only store stock remains.

Here's a great write up on the 810 https://panbo.com/airmar-dst810-multisensor-really-smart/

I get the dead rise angle isn't perfect, but I wouldn't be that concerned about 2*.

Airmar, for the most part, is the only maker of Transducers. Garmin now owns them, but prior most other companies that sold transducers were also made by Airmar under their brand. Furuno, Simrad and Raymarine to name a few.

 

[b_arrington]

Airmar, for the most part, is the only maker of Transducers. Garmin now owns them, but prior most other companies that sold transducers were also made by Airmar under their brand. Furuno, Simrad and Raymarine to name a few.

Where are you seeing that Garmin purchased Airmar? There's no indication of that on the Airmar website; it says they are still family owned by the founder. A search turned up nothing. Garmin did buy Vesper Marine in the last 2 years or so - they make AIS units.

 

[Skybolt]

Where are you seeing that Garmin purchased Airmar? There's no indication of that on the Airmar website; it says they are still family owned by the founder. A search turned up nothing. Garmin did buy Vesper Marine in the last 2 years or so - they make AIS units.

I thought they purchased them a few years ago. If not my bad, and sorry for the miss-information. To your point, might have confused that with the Vesper buy out.

EDIT: Still doesn't change the fact's about Airmar making all most all of the Transducers in existence even for other companies.