Integrating Stowe Dataline Instrument Displays

[lpdsn]

I'm just looking to compare notes with others who are trying to integrate Stowe Dataline with more modern instruments. I've seen the odd thread on this over the last year or two so I hope I'm not the only one.

I've an old Stowe Dataline set up. Definitely old and definitely Stowe (significant as it means the Dataline box will take in very little NMEA data and re-display it, unlike later versions which would be much easier to integrate).

Anyway, I really want to keep the displays as I can't find any modern instruments with a sufficiently low profile to replace them. Only the depth transducer actually works but the displays themselves are fine.

I've managed to integrate the Dataline to NMEA0183 and the N2K bus using a Shipmodule Miniplexer. As an experiment I'm generating VHW sentences from GPS VTG sentences. The displays are getting those and displaying them, so almost there, except...

They're not displaying the correct numbers. I half expected this as I believe the frequency of messages is somehow used in the calculation of the displayed value on the Stowe instruments. e.g. if it is expecting speed every 2 seconds and you send it every second the value displayed is twice what it should be.

Howevere, what I got wasn't quite what I was expecting. The speed display is showing about 5X the expected value, but using the same sentences the Dataline Central display is showing about 0.8X the expected value. So the two displays are behaving differently.

Anyone done anything like this before? Encountered similar issues? Or am I on my own?

 

[rudolph_hart]

I have Stowe/Robertson/Simrad IS11 instruments & when I had a Raymarine e7 touch-screen plotter fitted, the Engineer just couldn't get the e7 to accept anything from the Dataline 'bus.' I was told that's because Dataline 'isn't quite' NMEA 0183 standard.

Stowe Marine sell a NMEA interface box for the Dataline network. http://www.stowemarine.com/nmea.htm. They are also very helpful people.

Hope this helps.

 

[lpdsn]

I have Stowe/Robertson/Simrad IS11 instruments & when I had a Raymarine e7 touch-screen plotter fitted, the Engineer just couldn't get the e7 to accept anything from the Dataline 'bus.' I was told that's because Dataline 'isn't quite' NMEA 0183 standard.

Stowe Marine sell a NMEA interface box for the Dataline network. http://www.stowemarine.com/nmea.htm. They are also very helpful people.

Hope this helps.

Thanks. I've actually done quite well with the NMEA0183 messages. Some Stowe sentences are slightly non-standard but actually most are OK and are usable. So for example, only Stowe displays understand the DBK sentence, but I can convert DBT to N2K to get depth below transducer on the more modern displays.

In general though I'm trying to get data from non-Stowe transducers onto Stowe displays, whereas the box in your link seems to work the other way around.

I might try contacting Stowe. They might get to sell me a new display I guess.

Plan C is to just give up on the old displays and fit say two or three Garmin GMI20s, but I'd need to get someone to make me a new panel to give more space behind it, so it's not an easy solution.

 

[andyp]

I have no links with them but have always thought these guys look good.

http://www.tinleyelectronics.com

Their website includes a wide range of conversion projects including generic transducers to STOWE Dataline Instruments. They may at least be able to advise you on the different transducer signal formats (pulses per NM or signal frequency).

My own Dataline Databox has the RNav input so happily feeds NMEA out to the instruments, but from other threads I believe yours is an earlier model.

 

[rogerthebodger]

I also have an IS11 setup integrated into a PC using NavmonPC and OpenCPN using the output from the Databox using a standard RS232 to USB converter.

I also have an old SIMRAD chart plotter and Radar both connected to display data in each direction.

One think I found with a Raymarine speed transducer into the Databox is that the temperature sensing resister is of a difference valve and stoped the speed displaying from the Raymarine transducer but is OK with the Simrad transducer.

I just replaced the temperature connections with a fixed resistor of the correct value then all worked OK.

 

[lpdsn]

Thanks Roger, Andy,

I'm using OpenCPN too but have the data coming over USB from a ShipModul box sourced from Dataline and the N2K bus, as well as 0183 from the GPS & AIS. The only problem is feeding non-Stowe sourced sentences to the displays. And that problem isn't a basic fault as the displays do read the sentences, it's just their averaging algorithms give the wrong numbers, and even more curiously different displays do it differently.

I've no log transducer yet - the Stowe one is kaput and in the spare bedroom (I think) - I plan to fit a shiny new N2K one (DST800 looks nice). I'll leave that until after I know whether I can make use of the Stowe displays. There is nothing else that will fit the same space as all other manufacturer's displays would require my cutting into a structural member and weakening it.

The Dataline box will take GLL, GGA, HDM, MWV, RMB and VTG but won't retransmit them on the Dataline. I guess it wasn't bad for 1992.

If I understand correctly I think Tinsley now own Stowe. I think I probably will have to give them a call. I'll see what other contributions there are.

 

[roblpm]

I have updated a stowe data line system with the nmea box.

Tbh after paying to get the wind instrument refurbished, buying the nmea box, getting the dataline box repaired and trying to get the displays going I wish I had junked it all amd started again!

Just beware of spending too much money. And once you have started you will have to continue......

In fact maybe i should sell my whole dataline system and start again!

 

[lpdsn]

I have updated a stowe data line system with the nmea box.

Tbh after paying to get the wind instrument refurbished, buying the nmea box, getting the dataline box repaired and trying to get the displays going I wish I had junked it all amd started again!

Just beware of spending too much money. And once you have started you will have to continue......

In fact maybe i should sell my whole dataline system and start again!

I know what you mean. In normal circumstances I would probably have removed the Dataline stuff myself and got new stuff throughout, as I'm doing with the transducers. However, only the Stowe displays fit. I've searched the web and searched again and everyone else's displays stick out too much at the back.

I've fitted a couple of N2K displays even though they protrude into the cabins but I can do nothing more there. It also means I have the old trouble of crew sitting in front of the displays.

The original Stowe displays are ideally positioned, but if I try to replace them with anyone else's display there is no way of doing it without significantly weakening the structure behind them that supports the mainsheet. There is very little clearance between that and the instrument panel.

If I can get the things working I think I'm willing to buy new Stowe displays as the old ones give up the ghost. OK, they're more expensive than a new GMI20, but still it'll be OK if they work.

 

[Daverw]

Had a similar issue with depth of instruments, eventually went for raymarine wireless as displays can be flat fitted on bulkhead with no cutout required and solar powered so don't need any wiring. Meant that I could fit higher up in cockpit with clear view, I've been very pleased with them

 

[Boathook]

I know what you mean. In normal circumstances I would probably have removed the Dataline stuff myself and got new stuff throughout, as I'm doing with the transducers. However, only the Stowe displays fit. I've searched the web and searched again and everyone else's displays stick out too much at the back.

I've fitted a couple of N2K displays even though they protrude into the cabins but I can do nothing more there. It also means I have the old trouble of crew sitting in front of the displays.

The original Stowe displays are ideally positioned, but if I try to replace them with anyone else's display there is no way of doing it without significantly weakening the structure behind them that supports the mainsheet. There is very little clearance between that and the instrument panel.

If I can get the things working I think I'm willing to buy new Stowe displays as the old ones give up the ghost. OK, they're more expensive than a new GMI20, but still it'll be OK if they work.

I'm replacing my 20+ year old Stowe Dataline with an integrated system including a chart plotter. It works but just seemed erratic at times which I was getting fed up with. Anyway, I will have in a few months log (no temp and seems to under read) and wind transducer (refurbished in 2011) hopefully with mounts plus databox and 3 displays. Depth transducer staying in place at present to save me filling a hole and also I think that it is 'bonded' in place with sikaflec. I did look at the new Stowe items but didn't really like the displays and seeing that I keep looking at them when 'sailing' .............

 

[pvb]

The original Stowe displays are ideally positioned, but if I try to replace them with anyone else's display there is no way of doing it without significantly weakening the structure behind them that supports the mainsheet. There is very little clearance between that and the instrument panel.

Why not pad them out at the front?

 

[lpdsn]

Why not pad them out at the front?

I tried that with a NASA display. It's not very satisfactory as the padded-out display can be caught by the mainsheet when gybing (the arch that supports the instrument displays also supports the mainsheet and sprayhood). Edit: the gantry has grab handles which are big enough that they tend to protect the Stowe displays from the mainsheet but not more prominent displays.

My reserve Plan C is to actually build a brand new instrument panel from fibre glass with a brow to protect the instruments from the mainsheet and more space behind. I suspect getting enough space for instruments with N2K connections is probably impractical though, so I'm keeping that on the back burner.

 

[lpdsn]

I'm replacing my 20+ year old Stowe Dataline with an integrated system including a chart plotter. It works but just seemed erratic at times which I was getting fed up with. Anyway, I will have in a few months log (no temp and seems to under read) and wind transducer (refurbished in 2011) hopefully with mounts plus databox and 3 displays. Depth transducer staying in place at present to save me filling a hole and also I think that it is 'bonded' in place with sikaflec. I did look at the new Stowe items but didn't really like the displays and seeing that I keep looking at them when 'sailing' .............

Are you completely replacing the Stowe kit? I'm already part way through fitting a Garmin gWind. My main justification for having wind info is to feed it into the auto-pilot, so a straight N2K connection seems preferrable. Still, having a wind display on the gantry would be nice too. I currently don't have a log but was thinking of a DST800 giving N2K output. My Stowe depth works fine - and as Stowe and Airmar transducers work on different frequencies I plan to keep it even after I've fitted the DST800.

I suspect what I'm trying to do would be much easier with a more modern databox, so if you're selling in a few months might be worth talking. And if I can get the Stowe displays working, spares would be handy too. Mine are already 25 years old.

 

[[70521]]

I am always happy to take any Stowe kit that might be headed for the skip.

Currently the log paddle wheel is missing a magnet and I've love to get that working again, as I like to see the speed through the water along with speed over the ground.

 

[pvb]

I suspect getting enough space for instruments with N2K connections is probably impractical though, so I'm keeping that on the back burner.

You can get right-angle connectors which reduce the space needed.

 

[lpdsn]

You can get right-angle connectors which reduce the space needed.

I have an i70 (fitted elsewhere on the boat) and did try measuring it. The STng conectors themselves would protrude through the structural member even before I thought of putting any connections on the back. Even though you can get STng right angle connectors the siting of the connectors rather high up on the back of the instrument makes matters worse.

It's maybe easier to explain with a quick sketch (attached). This shows a cross section through the Aluminuim arch that supports the mainsheet and the instrument panel that is mounted on the face of it. Drawn only to an approximate scale as I haven't taken measurements from the boat for this.

The i70 would protrude through the upper part of this section so the connectors would be above the box section, so the face panel would have to be extended out a lot to make room for it and the right angle connector.

View attachment ArchCrossSection.pdf

If I did extend out the panel I suspect I'd mainly be aiming to fit GMI20s with NMEA0183 connections. There's plenty of room to run wires within the structure, but I wouldn't want to weaken it and would ideally like to reuse the existing small holes used by the Dataline.

 

[lpdsn]

I am always happy to take any Stowe kit that might be headed for the skip.

I have the anemometer in the spare bedroom. The windy balls are quite stiff so I guess the bearings will need sorting out. I managed to get it going for a while about 2009 but it siezed up during an unseasonally calm spell the following winter and I never tried again.

If you're interested in it, it's probably not worth posting, but if your being a cynical Scots engineer involves visiting the Firth of Clyde I could probably nip across sometime in the summer and hand it over.

I thought the log paddle was in there too, but can't find it.

 

[FarrGone]

I also have an IS11 setup integrated into a PC using NavmonPC and OpenCPN using the output from the Databox using a standard RS232 to USB converter.

I also have an old SIMRAD chart plotter and Radar both connected to display data in each direction.

One think I found with a Raymarine speed transducer into the Databox is that the temperature sensing resister is of a difference valve and stoped the speed displaying from the Raymarine transducer but is OK with the Simrad transducer.

I just replaced the temperature connections with a fixed resistor of the correct value then all worked OK.

Where did you patch the rs232 too on the dataline box?

 

[rogerthebodger]

Where did you patch the rs232 too on the dataline box?

Thats a good question

My post is 2017 5 6 years ago and not being on my boat currently I cannot remember now howI did the connection.

I probably connected the lines to the indicators to the RS232 recieve to the output of the IS11 which is in fact is rs422. I may have used a RS422 to RS232 converter but will need to check net time I an at th boat