What to do with old transducer for depth sounder?

[Lomax]

I have an old through-hull depth sounder transducer fitted to my boat, which I'm not sure what to do with. I don't have the matching head unit, nor do I know the brand or model of the transducer. I have been wondering what I should do with it, and can see a few options:

1. Remove it, weld up the hole and relax knowing the hull has no potential weak spots. With a draft of just 2' I can live without a depth sounder.
2. Leave it disconnected. It doesn't leak, so no harm having it there really. If it ain't broke etc.
3. Replace it with something more up-to date. I may not need a depth sounder, but it sure would be pretty neat to see what's down there.
4. Try to identify the model and see if I can locate a compatible head unit.

What would you do?

 

[William_H]

A lot of depth sounders will work on an old transducer making installation of a new system very easy. So it might be worth just leaving it there for a time until your needs evolve. If the old transducer won't work with new system then remove the old and fit the new.
However I would be inclined to remove and weld up the hole. (sounds like a steel boat) or GRP repair in a GRP boat. I have never had a depth sounder on my little boat finding that the keel works admirably as a sounder. olewill

 

[bitbaltic]

I have a redundant depth transducer which was one of a pair of log & depth transducers for my original NMEA0183 instruments. It became redundant when I fitted a combined N2K depth and log transducer in the hole for the original log through-hull. However the old depth transducer is still doing an excellent job of plugging the hole that was made to acommodate it in the first place. It has been doing this job for the last 15 years and I have no plans to retire it.

 

[Lomax]

Thanks guys! Looking at the Airmar DST800 "triducer" which measures depth, speed and water temperature and makes this data available over NMEA. This looks like something I'd be happy to consider a hole in the hull below the waterline for... Any experiences?

 

[Lomax]

It's a shame her hull is flat as a pancake, or I would consider an imaging sonar of some kind, but they all seem to have external elements requiring a protruding fairing. In the tidal waters of Britain, with such a shallow draft, I'm sure it would only be a question of time before it got ripped off by a rock (or a bicycle, or a shopping trolley...).

Edit: "tidal waters" - bad choice of words. I was thinking about the amount of time spent sitting on the bottom, as well as the hazards of the (obviously non-tidal) canal system and conflated the two images. One thing is for sure, a boat hull takes a lot of beatings in both environments.

 

[PaulRainbow]

Thanks guys! Looking at the Airmar DST800 "triducer" which measures depth, speed and water temperature and makes this data available over NMEA. This looks like something I'd be happy to consider a hole in the hull below the waterline for... Any experiences?

I have the NMEA 2000 version, works well. Should be OK to replace the existing one. If you don't fit a new one i'd leave the existing one where it is, as long as it's sound.

 

[PaulRainbow]

It's a shame her hull is flat as a pancake, or I would consider an imaging sonar of some kind, but they all seem to have external elements requiring a protruding fairing. In the tidal waters of Britain, with such a shallow draft, I'm sure it would only be a question of time before it got ripped off by a rock (or a bicycle, or a shopping trolley...).

Erm.... if you're venturing into water depths that would rip a faired transducer out of the hull you're not doing it right. Perhaps you really do need a depth sounder, the idea is that the boat goes in the wet bits, the dry bits are for your car

Where are you boating ? What boat ?

 

[Lomax]

Erm.... if you're venturing into water depths that would rip a faired transducer out of the hull you're not doing it right. Perhaps you really do need a depth sounder, the idea is that the boat goes in the wet bits, the dry bits are for your car

You've not been travelling much on the UK canal system then Encountering unidentified underwater objects is a daily occurrence, and you usually only become aware of them as they thump against the hull. I consider myself lucky as long as nothing wraps itself around the prop...



Edit: Yes, I know, it's the driveshaft on a truck. But just look at that thing. Someone's got their work "cut out"...

Where are you boating ? What boat ?

At the moment, the Medway and estuary, later the Thames and the Kenneth & Avon. Later still, the English Channel and the European waterways. She's a 45' "Dutch barge" type thing. 9' beam, 2' draft.

 

[Lomax]

http://www.worcesternews.co.uk/news...waters_of_the_Worcester_to_Birmingham_Canal/#

A mate of mine recently "found" a massive old riveted water tank, which he then spent an afternoon lifting out of the canal.

 

[Lomax]

Thinking about it, I should probably avoid a transducer with a paddle wheel log sensor...

 

[PaulRainbow]

You've not been travelling much on the UK canal system then

Nope, bit tricky with 1.8m draft and a 40 foot mast

You did say tidal waters in post 5 though and i can't say i've found many shopping trolleys in the North Sea. Have seen a few in tidal rivers though.

A depth sounder isn't likely to do you much good in the canals, but would be valuable when you venture out to sea. Given the canal use, i wouldn't fit the DST 800. I'd go for a plain bronze transducer such as the B117 or B60, you'll have a job to scrape one of those off with a shopping trolley

Edit : beat me to it with post #10

 

[Lomax]

Nope, bit tricky with 1.8m draft and a 40 foot mast

Nice! :encouragement:

You did say tidal waters in post 5 though and i can't say i've found many shopping trolleys in the North Sea. Have seen a few in tidal rivers though.

Yes, bad choice of words. I conflated the image of the Medway estuary at low tide with the (decidedly non-tidal) canal system - both pretty rough environments for a boat's hull. The type of boat I have encourages exploration of them both. Obviously, a large yacht with a non-retractable keel, would be ill advised to venture into either. But you do see a few keelboats on the canals, which always surprises me, and I'm just reading a book about a Swedish guy who uses the European canal system to get his massive bluewater yacht from the North Sea / Baltic to the med. He sends the mast ahead on a truck though

A depth sounder isn't likely to do you much good in the canals, but would be valuable when you venture out to sea. Given the canal use, i wouldn't fit the DST 800. I'd go for a plain bronze transducer such as the B117 or B60, you'll have a job to scrape one of those off with a shopping trolley

Yes. Shame you can't get a combined ultrasonic log sensor and depth sounder in one, but I guess they might interfere with one another. For some reason I got the impression that brass transducers were not recommended for steel hulls (galvanic corrosion maybe?) - but you can get them in stainless steel.

 

[PaulRainbow]

For some reason I got the impression that brass transducers were not recommended for steel hulls (galvanic corrosion maybe?) - but you can get them in stainless steel.

You're right, sorry, i forgot your boat was steel.

 

[Lomax]

Hmmm. I'm now thinking an ultrasonic log sensor might be more useful to have than a depth sounder. This one, for example, should fit in the old hole: http://www.p2marine.com/marine-electronics/airmar/airmar-cs4500-speed-transducer.shtml Speed through the water is a more interesting metric than water depth in my case.

 

[prv]

Yes. Shame you can't get a combined ultrasonic log sensor and depth sounder in one, but I guess they might interfere with one another.

You can actually - the Airmar DST900.

Suspect you won't like the price though - even the speed-only ST900 is nearly a grand

Pete

 

[Lomax]

You can actually - the Airmar DST900.

Suspect you won't like the price though - even the speed-only ST900 is nearly a grand

Pete

Thanks! There seems to be some confusion about whether the triple sensor version is actually available or not - I've only been able to find a speed & temperature one, and as you say, nearly a grand :hororr: I did find the Airmar DX900+ at www.jgtech.com, which does all three and more (including leeway logging and heel/trim sensing gyroscope!), for about the same price as the speed & temp ST900:

Accurately measuring leeway is arguably the holy grail of performance sailing analysis, but Airmar thinks it’s found the solution in a solid-state electromagnetic technology already used to monitor commercial fishing trawls. The DX900+ Multilog can purportedly determine both longitudinal and transverse speed through the water with nearly 0.1 knot accuracy, and thus can deliver precise real-time leeway speed and angle numbers. The retractable-for-cleaning MultiLog also contains a fast water temperature sensor, a depth sensor good to about 200 feet, and a combination of three-axis accelerometer and gyroscope that output heel and trim. When it ships in early 2017 for about $1,400, the DX900+ will come with an interface box that uses either NMEA 0183 or 2000 protocols to send this wealth of data to a boat’s instrument systems. But either box also notably includes Bluetooth 4.0 so that the transducer can be directly calibrated, configured, and updated with an included MultiLog phone or tablet app. The app may also be useful for monitoring the leeway speed and angle measurements since even many racing instrument systems will have to updated to best display and utilize these once mysterious values.

Rather outside my budget though.

 

[PaulRainbow]

Hmmm. I'm now thinking an ultrasonic log sensor might be more useful to have than a depth sounder. This one, for example, should fit in the old hole: http://www.p2marine.com/marine-electronics/airmar/airmar-cs4500-speed-transducer.shtml Speed through the water is a more interesting metric than water depth in my case.

The DST 800 is removable, so you could take it out and fit the bung when in shallow canals.

I'm not a fan of STW myself, i think SOG is of more value, in which case a cheap GPS will give you speed.

 

[MonniotC]

You've not been travelling much on the UK canal system then Encountering unidentified underwater objects is a daily occurrence, and you usually only become aware of them as they thump against the hull. I consider myself lucky as long as nothing wraps itself around the prop...

View attachment 63690

Edit: Yes, I know, it's the driveshaft on a truck. But just look at that thing. Someone's got their work "cut out"...


At the moment, the Medway and estuary, later the Thames and the Kenneth & Avon. Later still, the English Channel and the European waterways. She's a 45' "Dutch barge" type thing. 9' beam, 2' draft.

I'd stay away from the Leeds & Liverpool Canal if I were you. In West Yorkshire the pubs along the Canal have a trolley-chucking league instead of darts.

 

[Lomax]

The DST 800 is removable, so you could take it out and fit the bung when in shallow canals.

Yes. In fact one option is to just get the stainless steel housing and a blanking plug, and postpone the transducer decision.

I'm not a fan of STW myself, i think SOG is of more value, in which case a cheap GPS will give you speed.

I already have two GPS receivers, so SOG is well covered. STW is important mainly for fuel economy, for staying at optimal hull speed. Though I don't know what that is for my boat. Nor have I planned to install a flow meter on the diesel supply, so I won't be able to find out. Still could be an interesting statistic to log and compare with SOG, RPM, wind...

 

[Lomax]

That all said, what I would really like to have is some kind of forward/down looking imaging sonar. That would be really neat. Seems impossible to achieve without adding significant hull protrusions though