Harm in leaving sounder on?

[BDofMSP]

I'm in the middle of updating some electronics, including adding an AIS transceiver. I definitely don't want to have to leave it running while I'm out on the hook (consuming battery), but I would like to be able to keep it running when I'm on shore power, as sort of a poor man's theft detection system.

I have a toggle switch / breaker in the dash for the depth sounder right now. It's a 15 amp breaker so there's plenty of capacity (AIS draws 2 amps). I could add the AIS to that switch so that it could be shut off at anchor (or left on if our location was less safe), but I could leave that one switch on when I left for home. Of course this would leave the sounder on as well.

Any harm in leaving the sounder on? Other reasons why I wouldn't want to do this?

BD

 

[O C Diver]

First of all, I would want to leave the AIS at anchor, especially near waterways and navigation channels. On my boat the AIS is on a circuit that also powers the NMEA 2000 network. The network powers three 4" displays that display depth, wind, anchor drag alarm, and compass (boat orientation). All of this including the AIS draws less than 2 amps.

Ted

 

[BDofMSP]

First of all, I would want to leave the AIS at anchor, especially near waterways and navigation channels. On my boat the AIS is on a circuit that also powers the NMEA 2000 network. The network powers three 4" displays that display depth, wind, anchor drag alarm, and compass (boat orientation). All of this including the AIS draws less than 2 amps.

Ted

I agree that I'd want to leave it on any time that we would be anywhere near regular traffic. But in this scenario that would also leave my sounder on. Hence the original question of whether that's a problem or not. Since your list includes depth, I'm assuming the answer is "not".

 

[O C Diver]

I agree that I'd want to leave it on any time that we would be anywhere near regular traffic. But in this scenario that would also leave my sounder on. Hence the original question of whether that's a problem or not. Since your list includes depth, I'm assuming the answer is "not".

There are 2 different types of depth sounders. The more simple ones have a small chip that sees depth and reports it to the nmea network, low energy use and no moving parts. The more expensive transducers (that give you the graphics on your MFD may also have no moving parts but have either a more complex processor in a standalone electronics box or in the MFD. While they are probably as reliable, keeping the black box and or MFD on to utilize the information, seems excessive at anchor and may shorten the MFD's life.

Ted

 

[BDofMSP]

This one is the former. It has no Fishfinder capability. Just depth. It sends it over nmea 0183 to the ST60 Depth display. that display is powered independently. The MFD would not be left on.

 

[O C Diver]

I'm not familiar with the efficiency or chip within the NMEA 0183 transducers.

I'm assuming you are referring to a Raytheon or Raymarine ST 60 depth instrument. Found a manual (2004) online and would guess the transducer sees power wherever the unit sees power. IMO, the unit has already passed its life expectancy. May die tomorrow or 10 years from now. I would guess the display seeing power (whether it's displaying anything or not) will likely die first. No power to the display equals no power to the transducer. It will then probably fail the next time you power it up.

Ted

 

[BDofMSP]

Yeah it's almost 20 years old. It doesn't owe me anything. I decided I'm going to move the depth instrument to the same switch as the MFD. I will put the AIS on its own switch. Thanks for the input

 

[tpbrady]

I believe it is powered by the Seatalk 1 network, so all the old Raymarine instrument displays and sensors may have common power.

 

[Jeff F]

Many modern depth transducers burn out if run with the boat ashore. That may explain the switch.

 

[BDofMSP]

Great point. Thanks.
BD

 

[caltexflanc]

Many modern depth transducers burn out if run with the boat ashore. That may explain the switch.

But I think he is talking about leaving it on at the slip, with which there isn't a problem, but for which I can't figure out a reason.