AIS - VHF - Open CPN

[sailingharry]

Originally Posted by Jon Hacking

One thing about using OpenCPN is that it will be on your nav-computer, which really needs to stay at your nav-station. But with free screen-sharing & remote-control software (like TeamViewer) you can see & control your nav-computer from a tablet (or something) at your helm-station.

Good luck!

I've heard this a few times -- and twice today -- and I don't really understand the benefit.
A laptop/pi/etc at the nav station with OpenCPN is great. And, if you are comfortable with it, a tablet at the helm is great. What I don't understand is why you would want to control/mirror the nav station computer? On my boat, I have a Furuno at the helm, and networked in an identical Furuno at the nav station. Each works independently. I can zoom in an out at the nav station, go to North up (the helm is 99% head up), shift from raster to vector, plot a route, etc -- and my wife at the helm can do whatever she wants on the helm unit. Two INDEPENDENT devices on the same network. Not redundant -- they use the same power and GPS and such -- but each can be used independently. When a route has been programmed below, it is available on deck, but that's networking, not control.
Why would you want to use a tablet to mirror/control the nav station computer? What value does this add over simply running OpenCPN on both units, and using/controlling the one in front of you?
One possible biggie is that my Furuno system uses a "system license" meaning purchased charts are available on any unit on the boat. I'm not sure how the license for O-charts works for paid charts -- is it per device, or somehow per system? On the one hand, buying charts for every device is expensive, on the other hand having charts on one device lacks redundancy.

[Jon Hacking]

Excellent question, Harry. You're right, having 2 independent systems offers some excellent advantages. I was writing from the perspective of a cruising couple, where the person at the helm wants access to the sailing information, & their partner is doing something else (possibly on a computer, but on their OWN computer, not the nav-computer). I was also writing from the perspective of someone NOT in a first-world country with well charted waters.

You appear to be on the US east coast, which has pretty good charts (& the US gives them away if you want to download them). We've been in SE Asia for many years, & have found that pretty much all of the commercial charts are pretty poor here; often displaced from reality & very low resolution, especially when we get away from population centers (which, of course, is where we like to cruise!).

You mention chart prices. They can be pretty high, & they're not really designed for world cruisers who need a complete new set of charts for each new area they cruise to. Some companies allow you to exchange your old charts (chips) for new ones, but they're not very common. Paying for a worldwide set of charts can be VERY expensive.

So as I mentioned in my 2 paragraphs above the one you replied to, I've been making my own high-resolution & extremely accurate charts since 2014, mostly from satellite imagery, first as KAPs (a commonly used MapMedia format) & now as mbTiles, which allows more layers, higher performance, & much better colors (which turns out to be important when looking for a good sand anchorage &/or trying to avoid coral). They let you see into the water, usually to 30-ish feet (& often more) so you can see the extent of shallows & reefs, or even the bommies we get in the tropics (coral pillars that can rise from 100' to sit only a few feet below the surface).

These charts are extremely accurate, with max errors on the order of 10' (3m). Coral heads are easily visible, & they're exactly where charted. I make my charts from ArcGIS (usually very expensive), Bing (MSFT) & Google Earth satellite imagery, as well as from nautical sources like CMap & Navionics. Those last aren't as accurate, of course, but they have depths. A practiced eye can often tell approximate depths of satellite imagery water by its color, but having numbers on a chart is certainly useful. And I can switch between charts with only a single keystroke. So I can flip through all 5 of my charts in 2-3 seconds, to see which is best for my current situation.

But my charts are pretty big: for instance, Palawan (the long, skinny island jutting NE from the northern tip of Borneo) is 20GB. My charts for all of the Philippines are over 100GB. Indonesia is over 300GB.

While it takes me many hours to download the content & to then turn it into a nautical chart, all the tools & data are actually free on the web. If folks want to thank me for providing my charts, they're welcome to make a donation, but they certainly don't have to. After a nasty incident where a boat we were traveling with was lost because they trusted their Navionics charts too much, I'm now more interested in getting my charts into the hands of other cruisers than I am in making money. The cruising community has given us a lot in our 28 years of cruising, & this in one way I can pay some of that forward.

While it's possible for a tablet or similar device to run OpenCPN & to display my charts (& I agree with you that this would be a better solution) it's pretty difficult with today's technology, mainly because of the sizes of my charts. I'm sure this will change in the future, but with today's tech, it's cheaper & easier to simply control & display the nav-computer's screen, rather than trying to generate & display that information on a (small) helm device. You could use a laptop at your helm to accomplish this, but it's hard to make/find a weatherproof laptop. Again, easier & cheaper to use a tablet, possibly in a weatherproof enclosure (or moved below when in inclimate weather). If one of the crew wants to use the nav-computer to do something quickly, it's easy enough to tell the helm, but that's a rare occurrence on Ocelot.

Fair winds!

[sailingharry]

Jon,
Thanks for that explanation. It makes a lot of sense. On my simple two generation old Pixel phone, I have Navionics with the entire East Coast downloaded, and OpenCPN with the entire East Coast in raster charts. All fits very nicely in my memory with no issues. While I don't use it as primary, (and rarely even incidental) navigation, I use both occasionally for armchair navigation and have had no reason to wish I was controlling a remote computer.
With the charts you have developed, especially with your Google Earth satellite images, it makes sense that you have far more data than would fit on a phone. A downside to your approach, although the benefits far outweigh the downside! But using hundreds of gigabytes of storage certainly makes remote control a far better solution than a local app.

[westernspirit]

Back to original post question I have to echo what Evan (eheffa) said. Spent 4 months this summer mostly north of Cape Caution and often in deep fjords , including 4 days Princess Louisa, Starlink with good connection at least 90% of time with Predict Wind (and others). (Hate to say this because not a fan of company and CEO)

[sv_pelagia]

A year or so paying Starlink monthly fees (not to mention hardware costs), and you've paid for HF-SSB/HAM... just saying [emoji6]

[Maelruan]

SSB HF hardware costs have reduced greatly with development of tiny uSDX QRP transcievers with only 5 watts power (e.g https://www.eham.net/reviews/view-product?id=15133 or, https://dl2man.de/) .
The attached screen grab attached shows details of receipt of a GRIB this afternoon and display on OpenCPN. The antenna for this test is a long wire from a 2nd floor window.

[wholybee]

Originally Posted by sv_pelagia

A year or so paying Starlink monthly fees (not to mention hardware costs), and you've paid for HF-SSB/HAM... just saying [emoji6]

Not hardly. Only if you are doing a whole lot if DIY, and getting a deal on used outdated equipment. A years worth of Starlink is $1800. With hardware its about $2400.

Add up the cost of a good and reliable SSB, assuming no DIY, and not using some tiny SDR radio (which I strongly recommend against if you are relying on it.)
SSB Radio $2600 (current price at dockside radio)
Pactor Modem $1800 (current price at dockside radio)
Backstay insulators $265 x 2 (current price at defender)
Rigger work to install backstay connectors ~$1000 (varies a lot depending on rigger)
Dynaplate $183 (defender)
Other misc. supplies ($250)
Professional installation ??? (I strongly recommend a pro install unless you an and experienced HAM or some such.)

So not including the pro installation an SSB is upwards of $6300. You could run a Starlink for several years for that. If you only cruise part time, and turn Starlink service off for the off season, you might be able to stretch that to a decade.

Of course, you can do SSB cheaper, used radios from ebay, run a wire up a halyard for an antenna, and do all the setup yourself. But just a used SSB radio and use Pactor radio is probably going to be as much as Starlink for a year.

Having used SSB, Iridium Go!, and Starlink, SSB is my last choice both in useability and cost. If you've got it, its great for nets if you are into that sort of thing. And a DSC version is fine for emergencies, but I would still rather a 2way satellite device that works in the raft. SSB's time is past.

[wholybee]

Originally Posted by Maelruan

SSB HF hardware costs have reduced greatly with development of tiny uSDX QRP transcievers with only 5 watts power (e.g https://www.eham.net/reviews/view-product?id=15133 or, https://dl2man.de/) .
The attached screen grab attached shows details of receipt of a GRIB this afternoon and display on OpenCPN. The antenna for this test is a long wire from a 2nd floor window.

I would not even give the slightest consideration to a QRP radio without a proper antenna and ground plane as a source of critical information and communication while I was in the middle of the ocean. As a toy, it's great.

[Maelruan]

Hi Wholybee,
I have terrific fun adventuring and experimenting with my boat, and everything on it, "as a toy, it's great!"
Solo competitors on the last 2 Golden Globe Races had to rely on HF & some used it with WSPR low power to report positions - a sort of HAM AIS. They even had to use sextants!

[sv_pelagia]

Originally Posted by wholybee

Of course, you can do SSB cheaper, used radios from ebay, run a wire up a halyard for an antenna, and do all the setup yourself. But just a used SSB radio and use Pactor radio is probably going to be as much as Starlink for a year.

As suggested, SSB/Pactor paid off within 1 year of Starlink

(But I did say this somewhat tongue-in-cheek!)