Simple second depth Sounder

[Nasher]

I’m about to rip the dashboard out of The Nashers Revenge for what feels like the umpteenth time and rebuild it with the new instruments for the Opti I’m about to drop on the transom.

And once again I’m considering a mod that I’ve thought about for years.

My electronics package is quite old now, Raymarine C120, RAYSTAR 125 GPS Antenna, Raymarine DSM300 Sounder/Fishfinder module, Raymarine-Airmar in-hull Depth transducer, Navman 2100 Fuel Computer. Oh, and VHF -TBA as I need to replace it.
But it’s a robust package and all works very well.

The in-hull depth transducer is bonded in place a few inches forward of the transom and reads at all speeds, even when travelling quickly, but really comes into it’s own with the big screen showing the bottom in great detail when trawling around looking for a reef etc.
I really don’t want to swap all the gear out, as I certainly couldn’t afford to replace it with new equipment of a similar standard.

But of course the admittedly small issue is when nudging in to a beach etc the transducer at the transom is useless when the bow is 6.5M closer to a steep slope or shelf. Obviously a more forward mounted transducer would be useless at speed because only the rear of the hull is in the water, and the DSM only has input for one transducer.

When I worked for Raymarine I discussed at length with the design guys the possibility of mounting a second transducer nearer the bow, and finding a changeover switch which could ‘Hot Switch’ all the individual wires in the input cable between the two transducers.
Everyone I spoke to agreed it was theoretically possible, but really advised against it not knowing how the system would react.

So plan B all along has been to fit an independent very simple depth sounder gauge that can be switched on once the boat is off the plane, and set an alarm at the depth the engine skeg is below the water.
I’m lucky to have access to the hull below the deck all the way from just in front of the underdeck tank right to the bow, so can work out the best place to bond in a forward transducer and fit it easily enough.

Does anyone have any experience of these:
Hawkeye, which I like as the gauge fits well with the rest of the instrumentation.
https://seamarknunn.com/acatalog/Haw...r-CU17616.html

Or Nasa, which will probably be better quality, but look pants.
https://www.ebay.co.uk/itm/392790458...53.m1438.l2649

Perhaps SIMRAD
https://www.ebay.co.uk/itm/133811234...53.m1438.l2649

Or could recommend another make?

Not sure I’m even going to bother at the moment, but need to decide very soon.

Ta

Nasher.

[Pikey Dave]

Personally I wouldn’t touch NASA kit with the proverbial barge pole. Been there done that, cheap yachting sh1te. Ok below deck at a chart table, no place on a RIB console.
Look at the Vexilar sonar phone Tbox. I’ve got one on BP but never use it, it does work though. I bonded the transducer inside the hull at the side of the Airmar.

[Nasher]

Thanks PD, it's a good point about the NASA gear.

I really don't want to be going anywhere near anything that requires me to use my phone though.

[Orwell boy]

I had similar need for a depth reading as my garmin 750 had no depth facility ,i have also had hawkeye some years ago on a sports boat and it was never very succesful ,for me i just bought a garmin striker and solved all issues ,arralited the standard sensor in the hull and is super ,if you set the depth alarm at say 10 ft then once thats sounding the depth will fill the whole screen as a warning , of course you still have spare gps ,knots ,fish ,speed etc ,
https://seamarknunn.com/acatalog/Gar...100187001.html

[Nasher]

Thanks OB.

I've just realised that the NASA unit I referenced isn't a stand alone unit, and can only be used as a networked display.
I'd have to go for : https://www.ebay.co.uk/itm/384261492...53.m1438.l2649
But need to do some homework on it's suitability for outside mounting.

Nasher.

[Nasher]

I'm liking the look of this:
https://www.marinesuperstore.com/mar...som-transducer

But not the price

[Pikey Dave]

Originally Posted by Nasher

I'm liking the look of this:
https://www.marinesuperstore.com/mar...som-transducer

But not the price

Didn’t Hummingbird do a forward looking sonar at some time?

[Trello]

Originally Posted by Nasher

the possibility of mounting a second transducer nearer the bow, and finding a changeover switch which could ‘Hot Switch’ all the individual wires in the input cable between the two transducers.

Everyone I spoke to agreed it was theoretically possible, but really advised against it not knowing how the system would react.

Did you ever do this, Nasher?