Island suitable navigation gear

[RaymondR]

"Do the routes allow for the tide which is 1.5-2m/5-7'? The boat can draw (liftable rudders, no keels or boards) as little as 0.5m/20" so recommended tracks will change with the tide state."

I think you can set it up that way but I am accustomed to making the calculation from back in my pencil and paper days and always do it when I anchor and consequently haven't gone looking for it.

[rob denney]

Thanks. Please let me know what the devs (I assumed deviants, then thought about it and got developers. Says more about me than them!) say. A screen shot of the east coast of Fiji from Bau to leleuvia (same as the Navionics one attached would be cool.

[requiem]

Originally Posted by RaymondR

I have found the bathymetry on Navionics charts to be very poor in shallow waters. This is probably due to the lack of up to date surveys. However, I have found the dashed purple recommended tracks to be very accurate.

Do you know what is the source of the recommended tracks?

From the Navionics web viewer, there's a nice large "Incomplete Survey" warning between Bau and Leleuvia, and from a quick eyeball I suspect they're using the same data from the UKHO chart of the area, which was surveyed back around 1880.

CM93 charts (which I also suspect use the same) include this helpful warning: "Examination of aerial photography of the area indicates that additional coral pinnacles exist over which the depths are uncertain."

The NZ charts do not have sufficient detail for the area; here is what they look like, with some satellite overlays...



Compare with the UKHO charts and sat view...

[RaymondR]

"Do you know what is the source of the recommended tracks?"

No, but I do know that when I used them to ascend the Fitzroy and Mary Rivers on the east coast of Australia, moving off them leads one into shoal waters. These rivers are resurveyed after floods for the replacement or relocation of navigation marks after floods consequently there may be an official source.

[Be Free]

Originally Posted by RaymondR

Does OpenCPN support N2K.

I probably need an update but it did not the last time I looked.

NMEA 0183 is far simpler to use and unless one wants to run radars from a MFD does more than sufficient for navigation and autopilot control and is far simpler and more usable than Lighthouse.

The version of OpenCPN currently in alpha testing supports N2K natively.

[rsementi]

Hello Rob, great to see your post! Hope all is well and good luck on the proa!!

[Kit_L]

Excellent post, and the best of luck with Harryproa! Joining thread to learn about all the alternatives there seem to be to MFDs.

[nofacey]

Talk with these guys - provide hardened laptops for commercial fishermen, for very reasonable $$
No relationship, they just look like they fit your needs.

https://navigationlaptops.com/

AND - previous comments on sh*tty charts in FIji are absolutely true - so many uncharted reefs in places you’d think you were using roadmaps. On top of which, if it wasn’t an area used by big commercial traffic, the navigation aids aren’t maintained - more often than not, they weren’t there.
SAS Planets was wayyy more useful than standard charts.

[Jon Hacking]

Originally Posted by rob denney

Thanks. Please let me know what the devs (I assumed deviants, then thought about it and got developers. Says more about me than them!) say. A screen shot of the east coast of Fiji from Bau to leleuvia (same as the Navionics one attached would be cool.

Fascinating project, Rob.

The best charts for navigating through reefs, by FAR, is satellite imagery. This has been touched on above.

I believe Ovital has died, but there are apparently other options for iWhatsIts that can get access to Google Earth (GE) & perhaps Bing imagery. That's probably simplest & cheapest, although you'll probably want a backup.

We use a laptop running OpenCPN down below, connected by WiFi to any tablet or computer at the helm with screen-sharing SW like TeamViewer. That way, the nav-computer is safe down below.

But the charts are the critical part for you. We make perfectly geo-referenced navigational charts from GE, Bing, & ArcGIS (with other sources available) as well as from nautical sources like CMap & Navionics. These last aren't as accurate as the satellite imagery (which has max errors on the order of 10' or 3m) but they do offer depths, which can be useful. While I plan to make downloadable charts for Fiji soon, I haven't done so yet, & I don't know your time-line. Also, while I give these away to the cruising community, I ask commercial entities to please donate $100.

Or, if you've got a lot of time & internet bandwidth on your hands, I've published a How-To guide to Making mbTiles, which is a map-type readable by OpenCPN. I've tried to write it so even novices can produce high-quality, high-resolution navigational charts, so I welcome feedback & questions, so I can improve the page.

The 6 attached images show a bit of what's possible, although the first 5, showing the same area between Ovalau Island & East Viti Levu (in ArcGIS, Bing, GE, CMap, & Navionics) are really too high to show much detail. They're really just comparison shots, but OpenCPN can switch between them with just a single key-stroke, so the helmsperson can tell which chart is the best for them at that instant in about 2 seconds. Even the final image, of the south end of Ovalau Island (Nukutocia Bay) is a relatively low-resolution shot, as much more detail is possible.

[Jon Hacking]

This image, of the pass to get through the reef at the south end of Ovalau Island, shows the sort of resolution that's possible. This is the highest resolution I generally go to. You can see that individual coral heads (& waves) are visible, & it's even possible to pick out some coral at the bottom of the channel, which is 20-30m deep. Not only are CMap & Navionics very low-resolution for this pass, but they also don't agree even with each other, as they're both offset somewhat.

[rob denney]

Wow, amazing stuff. I had decided to go with Garmin/Simrad but these last few posts have changed that. I will discuss it with Steinar (design partner building this) who is visiting next week for the northern (as in north of the Arctic Circle) winter. He is far geekier than me. Expect a bunch of questions over Xmas. Thanks.

[Jon Hacking]

Originally Posted by rob denney

Wow, amazing stuff. I had decided to go with Garmin/Simrad but these last few posts have changed that. I will discuss it with Steinar (design partner building this) who is visiting next week for the northern (as in north of the Arctic Circle) winter. He is far geekier than me. Expect a bunch of questions over Xmas. Thanks.

Happy to talk about this more, Rob. ATM we're off Ocelot & visiting friends in the US for the holidays, so moving around quite a bit, with reduced connectivity. And from about mid-Jan thru mid-Feb we'll be in Antarctica, so out of touch (& then in South America into June, so possibly reduced connectivity).

Perhaps email is better for this. If you PM me I can send you my eddress.

[requiem]

Originally Posted by Jon Hacking

We use a laptop running OpenCPN down below, connected by WiFi to any tablet or computer at the helm with screen-sharing SW like TeamViewer. That way, the nav-computer is safe down below.

A bit of a foolish question here, but has anyone considered flush-mounting a touch-screen all-in-one PC, similar to an MFD? The idea being to provide full-size PC capability in a weather-resistant format.

I know at that point the question is "why not just use an MFD", but this is where my common complaint about current MFDs comes back into play: insufficient navigational tools.

[Jon Hacking]

Originally Posted by requiem

... has anyone considered flush-mounting a touch-screen all-in-one PC, similar to an MFD? The idea being to provide full-size PC capability in a weather-resistant format...

Most laptops aren't very water resistant, Requiem. They're fine in the pilot-house of a trawler or inside steering station, but I wouldn't want to leave one outside. We don't even put an MFD out there. That's why we leave our nav-computer at the nav-station of our sailing catamaran, & only take a tablet or smaller computer to the helm.

But if you find something that works, please let us know.

[requiem]

Originally Posted by Jon Hacking

Most laptops aren't very water resistant, Requiem. They're fine in the pilot-house of a trawler or inside steering station, but I wouldn't want to leave one outside.

Indeed; what I had in mind was an all-in-one sort rather than a laptop; similar to an iMac where everything is built into the display. I think they may be refered to as panel PCs in industrial use? The idea being to expose only the glass display, seal around the edge of the display, and any non-waterproof parts, vents, etc are safely contained in the mounting enclosure.