AIS silent mode

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BernieA
Posts: 84
Joined: Feb 22nd, '18, 20:20

AIS silent mode

Post by BernieA »

I installed an AIS transponder a few days ago and found in the manual the option to add a switch to silence transmission and operate in receive only mode. Other than smuggling,which I don't do, can anyone suggest any reason for using receive only mode?

Bernie
CD28 Pinafore
Sequim Bay Washington
John Stone
Posts: 3621
Joined: Oct 6th, '08, 07:30
Location: S/V Far Reach: CD 36 #61 www.farreachvoayges.net www.farreachvoyages.com

Re: AIS silent mode

Post by John Stone »

Sure. I use receive only to save power offshore as it uses much more to transmit than just receive. So if I am up and about in the boat I switch to receive only and just scan the horizon every 20 min. When I am going to sleep I switch the AIS to transmit. If I was double handing I probably would not transmit at all.

Also, not so much here in the US but there are plenty of places in the world where you might want your AIS to receive but not send a signal informing others where you are, who you are, or what direction you are headed.
BernieA
Posts: 84
Joined: Feb 22nd, '18, 20:20

Re: AIS silent mode

Post by BernieA »

Good points. I sail in the Salish Sea, Puget Sound, San Juan and Canadian Gulf Islands. There's a lot of traffic and often unpredictable fog settling in, so I plan to leave it on any time we're out on the water.
Thanks for clearing that up.

Bernie
BernieA
Posts: 84
Joined: Feb 22nd, '18, 20:20

Re: AIS silent mode

Post by BernieA »

John,
I'm curious, since you sail offshore, do you have a Class A or Class B transponder? I checked the current usage of the class B that I installed and it appears to draw only 1/3 amp, without a significant jump when it transmits a burst of data. The max I've seen then is still less than 1/2 amp. Since class A also transmits a satellite signal, I would expect it to use more power. This class B seems to be pretty efficient. We don't sail offshore since we're pretty far inland with a lot to explore. Besides, my wife would kill me before we got as far as the north Pacific. I've been a dinghy sailor since I was 14, which was a long time ago. I'v done some inland keel boat sailing for a week each summer for about ten years, but didn't own a larger boat until 2 years ago. I still have the dinghy, a 1960 Enterprise class built from Mahogany.
Bernie
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John Stone
Posts: 3621
Joined: Oct 6th, '08, 07:30
Location: S/V Far Reach: CD 36 #61 www.farreachvoayges.net www.farreachvoyages.com

Re: AIS silent mode

Post by John Stone »

BernieA wrote:John,
I'm curious, since you sail offshore, do you have a Class A or Class B transponder? I checked the current usage of the class B that I installed and it appears to draw only 1/3 amp, without a significant jump when it transmits a burst of data. The max I've seen then is still less than 1/2 amp. Since class A also transmits a satellite signal, I would expect it to use more power. This class B seems to be pretty efficient. We don't sail offshore since we're pretty far inland with a lot to explore. Besides, my wife would kill me before we got as far as the north Pacific. I've been a dinghy sailor since I was 14, which was a long time ago. I'v done some inland keel boat sailing for a week each summer for about ten years, but didn't own a larger boat until 2 years ago. I still have the dinghy, a 1960 Enterprise class built from Mahogany.
Bernie
The attachment PA160034.JPG is no longer available
Bernie
Wow! That’s gorgeous! She looks pristine. Where do you sail her?

I love dinghy sailing—same as you that’s how I started sailing at about 10 years old. I bought Roger Barnes book The Dinghy Cruising Companion a couple years ago and it is just fantastic. If I didn’t have the FR I could be very happy camp cruising on an Ian Oughtred designed dinghy like the Arctic Tern or an Ilur or whatever. Dinghy camp cruising is an order of magnitude less expensive than sailing a big keel boat. And there’s is a lot of enjoyment to be had there. But, I digress....

AIS. I have a class B. It’s a Vesper Watchmate 850. Draws 1.5ah in transit mode and .3ah in receive only mode. We don’t have an engine and the only way we can charge the battery is with a 30 watt solar panel so power usage is important to us. Here is what we have: https://farreachvoyages.net/2016/04/13/ ... w-has-ais/
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Vesper Watchmate 850
Vesper Watchmate 850
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BernieA
Posts: 84
Joined: Feb 22nd, '18, 20:20

Re: AIS silent mode

Post by BernieA »

The dinghy is a Jack Holt design that won the London Times contest in 1956. We've sailed it on the Columbia and Willamette Rivers, and lakes in Oregon, Washington, Missouri, Kansas, and Arizona. It's only dip in Salt water was in Tillamook Bay back in the '70s. There are thousands of them in Great Britain and other colonies. Very few in North America, and only two that I know of on the west coast.
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