Depth sounder integration

[Murv]

I have a couple of ancient Stowe depth sounders that are a little temperamental.
When they're working, they're great and give accurate depth soundings.
However, inevitably, when they decide not to work it's as I'm picking my way across somewhere dodgy so they need to go...

Existing MFD's are a Raymarine E120 at the lower helm with an E80 acting as a repeater on the flybridge.
The chandlers advice is to rip them both out and replace with up-to-date units, which I'm not going to do.

The options seem to be:

1) Buy the Raymarine fishfinder module which will interface with the E120 and thus also show the depth readings through the E80 on the flybridge.

2) Buy one of the small standalone downvision fishfinder units (Humminbird looks good?) that will connect through seatalk/NMEA to the E120

3) Buy a standalone unit, mount it on the flybridge and then transmit that info wirelessly to a tablet mounted on the lower helm. (the thinking being that I need the water resistant qualities of a marine unit on the flybridge)

There appears to be pros and cons to all the options, they will all cost similar money but the benefit to options (2) & (3) would appear to be a separate depth/bottom contour display without having to split screens on the Raymarine units.

Whilst I very much don't want to replace the existing MFD's, I also have to bear in mind that they're approaching 10 Years old now so it would be nice if whatever depth sounding solution I go with could interface easily with current kit if I do have to replace something major in the future.
But, with the depth sounding options costing low hundreds rather than the thousands that the MFD's will cost, that is a minor requirement.
The only reason I'm thinking along the lines of downvision fishfinders is that I've used them in the past and as a major fan of gadgets, I do find it fascinating what the bottom looks like.
However, I've also discovered that is is very much just for interest and the depth reading is the primary consideration!

Also, just to throw this into the mix, I need some way of getting engine temperature readouts to the flybridge although I imagine this will have absolutely no effect on the above (just in case there's some kind of multi-interfacing new fangled thingy that I've never heard of out there)

I know absolutely nothing about marine electronics, so my understanding of what will interface to what may be way off so any advice greatly appreciated.

 

[jfm]

Most modern echo sounders, ignoring the base level ones, have transducers wired to a computer box, and the box sends its video to the MFDs via Ethernet. You might find the E120 is sufficiently modern that it can read the Ethernet from a new sounder, and in that case the sounder would also work if you upgraded the MFDs

Of course, if you don't want to use up your existing screen area then go with options 2 or 3, but the video/Ethernet output from these wont be compatible with MFDs you might buy in the future from the major manufacturers. The depth number will be, via n2k.

If you want all singing/dancing temp displays on your MFDs you need to get the temp data onto the n2k bus, or so called STNG in raymarine speak, and then you can see it on any screen. Maretron TMP100 will do this for you. Maretron is top quality equipment

 

[Murv]

Thanks jfm, very useful stuff.
It appears that the Raymarine high speed seatalk is actually an ethernet connection, so should be OK with an ethernet sounder box.
I will confirm with Raymarine before buying anything though.

The Maretron looks a very useful piece of kit indeed!

 

[jfm]

Thanks jfm, very useful stuff.
It appears that the Raymarine high speed seatalk is actually an ethernet connection, so should be OK with an ethernet sounder box.
I will confirm with Raymarine before buying anything though.

The Maretron looks a very useful piece of kit indeed!

Yes, but only one of their seatalks is Ethernet. Raymarine have used various sea talks:

ST1 - nmea0183 language with bespoke raym connectors [no, ignore that, see corrections below]
st2 - nmea2000 language with horrible clumsy raym connectors - even raym realised this was rubbish and withdrew it
stng - nmea2000 language with better but still annoying connectors. Modelled on generic connectors but slightly different
st HS - this is ethernet

If your plotters have a st HS connections (I think they do- RJ45 socket on back) then yes you can plug in Ethernet devices like sounder computers. But I wouldn't expect plug and play with anything other than Raymarine products! good luck

 

[Murv]

Thanks for that, 'tis all very confusing!

I appear to have (according to the online manual)

NMEA 0183
Seatalk 1
Seatalk 2
Seatalk high speed
Seatalk - Alarm out

I will check on the back of the actual unit to see if that is the case, but it looks then as if I'll be restricted to a Raymarine unit unless I connect through the NMEA 0183 port which is labelled as "third party" applications.
There is actually an open day at the local chandlery which a Raymarine rep will be attending, so that could be a good chance for me to see what's possible. Provided, of course, that I don't get talked into just buying a whole new Raymarine system!

 

[oldgit]

Look its dead simple.....when you hear your props going clink clink clink....theres probably not enough water when they go clunk clunk theres definately not enough water.
Problem with the standalone depth thingys is the weeny screen size and getting the signal all round the boat.
Personally would keep an eye on ebay or elsewhere for a Raymarine Digital fishfinder . ?
Why on earth they appear seems a bit daft,why buy and not fit or even more mysterious why remove an existing unit.
Unless of course somebody has upgraded and selling off the bits seperately.

 

[jfm]

Thanks for that, 'tis all very confusing!

I appear to have (according to the online manual)

NMEA 0183
Seatalk 1
Seatalk 2
Seatalk high speed
Seatalk - Alarm out

I will check on the back of the actual unit to see if that is the case, but it looks then as if I'll be restricted to a Raymarine unit unless I connect through the NMEA 0183 port which is labelled as "third party" applications.
There is actually an open day at the local chandlery which a Raymarine rep will be attending, so that could be a good chance for me to see what's possible. Provided, of course, that I don't get talked into just buying a whole new Raymarine system!

OK but remember they are generic things that Raymarine, working with the devil, has tried to pretend are proprietary so they can sell you connectors at £50 ea. NMEA013 is a limited slow connection and you'll only be able to receive a depth number on it (from a nmea0183 transducer), not a video style modern sonar display

 

[prv]

ST1 - nmea0183 language with bespoke raym connectors

Sorry John - Seatalk (1) and NMEA 0183 are almost entirely unrelated. Similar era and speed, but that's about it.

NMEA is a one-way channel with only one sender and a very small number of listeners (officially only one, but you can usually stretch it to three or four). If you want multiple devices talking, each of them will do so on their own one-way set of wires, which you need to run to whatever other things want to listen to that particular data. It isn't really a network as such, just a collection of different physical point-to-point links that happen to exist on the same boat. The data is sent as "sentences" in somewhat human-readable ASCII text.

Seatalk is a true multi-drop network with one shared medium (like the VHF airwaves) on which all the instruments can talk and listen to each other, checking that nobody else is currently talking before they butt in. So you don't need to worry about what data needs to get where, just put it "on the Seatalk" and whatever needs it can get it. The data is purely binary, and the packets and their structure bear no relation to any NMEA sentences.

All correct AFAIK with the newer stuff though :encouragement:

Pete

 

[Murv]

Thanks all, much appreciated.
Fred, I tried the clunk clunk method... and I don't like it!

Raymarine DSM modules are available (mostly from the states) second hand. With transducer this option is around £450.00.
Advantages: Neat and fully intergrated. Disadvantages: no downvision and will have to split screens to view sonar. Also, 2nd hand so no warranty and maybe limited lifespan.

The Humminbird Helix 7 can be flushmounted at one station, connected to the E120 which would give me a dedicated fishfinder screen as well as just a depth figure on both E120 & E80 (if I've understood correctly)
This option is around £400.00.
Advantages: Single dedicated sonar/downvision display, available new. Disadvantage: Only one detailed screen available where the unit is mounted.

Or... for around £200, I could flushmount a Raymarine Dragonfly 4 pro at the flybridge, and just connect through its wifi to a phone or tablet at the lower helm.
This would give me two dedicated, separate sonar & downvision displays, I won't have to try and connect anything to the E120 so won't have to split screens further and is significantly cheaper as well as being brand new.
Advantages: as above. Disadvantage: none?

Any reason that the Dragonfly wouldn't be the best option?

 

[jfm]

Sorry John - Seatalk (1) and NMEA 0183 are almost entirely unrelated. Similar era and speed, but that's about

Thanks Pete. Yes as as soon as I read that I knew you were correct and that I was talking tosh on ST1. I must be getting old- I've spent many hours wiring ST1 and NMEA 0183 thru multiplexers side by side on same boat then forget it all when writing a post on here! All the plug and play n2k back boning of recent years has addled my brain. Time to go boating. Thanks for the correction!