AIS connected to "hot battery bus" - why?

[wonkywinch]

If I turn off the domestic & engine power switches (and the the negative), the switch panel and fuse panel behind stays powered up when the boat is on shore power and the battery charger is switched on. It's quite handy so I can leave the bilge pump on auto but it also means the AIS is permanently on and transmitting and I'm not sure if this is the "done thing"?

I need shore power connected for the heater and dehumidifier in the winter but wondered why Beneteau connected the electronics to a hot battery bus (excuse aeroplane terminology, I don't know what it's called on a boat). The "navigation" switch kills the chart plotter etc and I wondered whether to move the AIS power across to that feed.

 

[Refueler]

I cannot see any advantage in having it powered permanently ??

I have mine integral with y Onwa Plotter - so when plotter is without power .. AIS shuts down as well ..... (note that if power is stil connected but plotter switched off - the AIS part of it still active).

Bus is correct ...

 

[ash2020]

Why not just put a switch into the power to the AIS?

 

[davidej]

I wish you would tell the literally hundreds of yachts in UK marinas to turn the B things off!

Great at sea but in a marina?

 

[wonkywinch]

Why not just put a switch into the power to the AIS?

Because a whole fuse block is permanently powered. There are other electronics hanging on there (eg, antenna splitter etc). I'd rather find out why the manufacturer did this before I rewire the whole feed and switch that rather than chop into a single cable for the AIS. As DavidEJ witnesses, the AIS is just the visible side of the francais way of wiring up electronics.

 

[Refueler]

I agree with matey ... just put a switch or move the power take-off to the Instrument switch that also supplies plotter etc. ??

As to the whole fuse block powered .. I'd be into sorting that out ... with a power breaker.

 

[Refueler]

I wish you would tell the literally hundreds of yachts in UK marinas to turn the B things off!

Great at sea but in a marina?

Wouldn't be so bad if they changed the 'mode' to In Port ... then at least alarms would stop

 

[oldgit]

One skipper leaves his AIS on all the time.
Monitors it from home.
If the boat starts to move..!

 

[MontyMariner]

I accept that some kit is permanently powered, such as a bilge pump, solar and boat alarm but find it incredulous that instruments are not wired through a main isolator switch.
Plus I thought that AIS transceivers all have a 'stealth mode' so the transmitter can be switched off.

 

[Refueler]

One skipper leaves his AIS on all the time.
Monitors it from home.
If the boat starts to move..!

Fine ... but In Port mode will do the same ... it still gives position etc. Just limits the alarm condition.

 

[Refueler]

I accept that some kit is permanently powered, such as a bilge pump, solar and boat alarm but find it incredulous that instruments are not wired through a main isolator switch.
Plus I thought that AIS transceivers all have a 'stealth mode' so the transmitter can be switched off.

Usually AIS has "In Port" or At sea" modes (or such terms as brand decides) when powered ... plus of course full on/off ...
Some AIS do allow you to switch off TX part ... the ONWA has that ...

 

[Amlov]

Sometimes the VHF is wired on a separate fused circuit that is permanently powered, along with the bile pump. I assume this is a ‘safety’ feature and it looks like the AIS has been wired on this circuit. If the AIS has a VHF splitter that only works when powered, which I don’t think any do, then there is some slight logic in this. But there is much more logic in being able to turn it off or silence it when you don’t need the AIS.

 

[PaulRainbow]

Usually AIS has "In Port" or At sea" modes (or such terms as brand decides) when powered ... plus of course full on/off ...
Some AIS do allow you to switch off TX part ... the ONWA has that ...

There is not such option on class B AIS, sadly. There is a "stealth" mode, where the AIS receives only, no transmit, but this would be pointless when leaving the vessel unattended. Just turn the damn thing off Grrr

 

[oldmanofthehills]

+1 to Rainbow

The amount of pointless pollution by light and other radiation that us First World folk produce, is astonishing. Turn things off when you leave building or boat

 

[Refueler]

There is not such option on class B AIS, sadly. There is a "stealth" mode, where the AIS receives only, no transmit, but this would be pointless when leaving the vessel unattended. Just turn the damn thing off Grrr

ONWA actually along with other such as Matsutec - DO have IN Port mode ... as well as option to turn off TX ..

That's for the older B class and later B+ class models.

But I do agree ... switch off when unattended at mooring.

 

[davidej]

One skipper leaves his AIS on all the time.
Monitors it from home.
If the boat starts to move..!

And F to the rest of us!

 

[dunedin]

One skipper leaves his AIS on all the time.
Monitors it from home.
If the boat starts to move..!

Nowadays there seem to be loads of boats leaving their AIS transmitting all winter when stored ashore in a cradle, and unable to move unless lifted by a large yard hoist.

 

[wonkywinch]

It's a B&G NAIS500 which has a silent mode option switched via a pair of wires (no option on chart plotter). I did fit a switch for "stealth mode" but it's behind the hinge instrument panel. I'd rather depower the whole electronics kit so I don't hurry it towards the right hand side of the bathtub curve.

 

[MontyMariner]

I did fit a switch for "stealth mode" but it's behind the hinge instrument panel.

Why would you put it there?

I'd rather depower the whole electronics kit so I don't hurry it towards the right hand side of the bathtub curve.

You will probably have sold the boat long before it takes a bath!

 

[Neeves]

If I turn off the domestic & engine power switches (and the the negative), the switch panel and fuse panel behind stays powered up when the boat is on shore power and the battery charger is switched on. It's quite handy so I can leave the bilge pump on auto but it also means the AIS is permanently on and transmitting and I'm not sure if this is the "done thing"?

I need shore power connected for the heater and dehumidifier in the winter but wondered why Beneteau connected the electronics to a hot battery bus (excuse aeroplane terminology, I don't know what it's called on a boat). The "navigation" switch kills the chart plotter etc and I wondered whether to move the AIS power across to that feed.

There is the thought that if the bilge pump fails then were the vessel to sink you would know something was amiss as the AIS would stop transmitting.

I believe something similar was used by radio operators when their vessel was sinking.

Jonathan