Chart plotter suggestions / sense check please

[tillergirl]

Navionics make daily updates.

The fact that Navionics provides updates automatically does not mean that it updates all changes. Please do not fall into that trap. I have been monitoring Navonics (with daily evidence) a significant change which the UKHO issued on 25 March, 2025 (yes 2025) but Navionics has still not changed it.

 

[dunedin]

Navionics make daily updates.
……

Navionics does do daily updates. BUT most of the Hydrographic Offices, including UKHO, do not currently issue their source data updates to leisure chart publishers that frequently. It can be several months before the HO issue chart updates.
So all you get with a “daily update” is the other changes (not the official HO data) - eg user updates, any updates applied manually by Navionics staff, and any new specialist sources (eg harbour surveys).

 

[Baggywrinkle]

The fact that Navionics provides updates automatically does not mean that it updates all changes. Please do not fall into that trap. I have been monitoring Navonics (with daily evidence) a significant change which the UKHO issued on 25 March, 2025 (yes 2025) but Navionics has still not changed it.

Interesting, what was the change and do you know why it was not included? Updated isn'T a guarantee on particular sources, it gets updated from hundreds of sources.

Navionics does do daily updates. BUT most of the Hydrographic Offices, including UKHO, do not currently issue their source data updates to leisure chart publishers that frequently. It can be several months before the HO issue chart updates.
So all you get with a “daily update” is the other changes (not the official HO data) - eg user updates, any updates applied manually by Navionics staff, and any new specialist sources (eg harbour surveys).

I find the crowd sourced stuff for the area I sail very useful, and with the exception of one bay where the zoomed in position was offset, I've never encountered a serious problem. There is a reason why every chart-plotter claims to be "an aid to navigation" rather than an oracle of truth, and the word "uncharted" exists because for centuries users of charts have been finding errors or corrections.

If used commercially, then the standard has to be higher as there is far more at stake, so the sources are deliberately limited, but ultimately the skipper is responsible for proper selection and use of the tools at their disposal.

The Navionics sources, which are many, are listed here ...

Garmin

The UKHO are in there with the following note:

“This product has been derived in part from material obtained from the UK Hydrographic Office (UKHO) with the permission of the UK Hydrographic Office (UKHO), Her Majesty’s Stationery Office, and the following authorities: “© National Hydrographic Office (NHO), Sultanate of Oman, 2019”, “© Netherlands Hydrographic Office (NLHO), 2019”, “© Insituto Hidrogràfico de la Marina (IHM), 2019”, “© Instituto Hidrogràfico, Portugal (IHPT), 2015”, “© Vlaamse Hydrografie, 2019”, “© Servicio de Hidrografía Naval (SHN), 2019”, “© Malta Maritime Authority (MMA), 2019”, “Hrvatski Hydrografski Insitute (HHI), 2021”, “© British Crown Copyright, 2019 “ Notice: The UK Hydrographic Office (UKHO) and its licensors make no warranties or representations, express or implied, with respect to this product. The UKHO and its licensors have not verified the information within this product or quality assured it.”

Google does very well on real-time road mapping, and often gets transient problems like road-works, diversions etc right, planning them into the calculated route. Crowd sourcing is a fantastic source of real world data if the process to clean it is robust.

 

[LittleSister]

. . .
OK ... but consider the draft of some of those ships ... I sailed on ships that had over 75ft draft .....

I hope you got the expected pay-off in reduced leeway when beating to windward.

 

[dunedin]

The fact that Navionics provides updates automatically does not mean that it updates all changes. Please do not fall into that trap. I have been monitoring Navonics (with daily evidence) a significant change which the UKHO issued on 25 March, 2025 (yes 2025) but Navionics has still not changed it.

You asked in post #16 - “Do you think that Navionics regularly update?”

I think it is pretty certain that Navionics does regularly apply updates - albeit as noted in my post #22 above, the official Hydrographic Offices feeds typically do not provide anything like daily updates, some can have a delay of several months.
For example, as you know (and referred to at the recent RIN conference) the work with the RIN - with your and others assistance - showed in one case a circa 6 month delay between a spring survey of the River Deben being performed before the UKHO issued the chart updates (unfortunately missing an entire sailing season - hence why the ECP online sources are so valuable).
But this was a delay in the data provision by the HO.

Not sure what the example you are referring to now is (from March 2025) but can you advise:
(A) If and when it was updated in the official UKHO charts ?
(B) If and when this was updated in other commercial leisure charts such as
(I) C-Map
(II) Lighthouse Charts
(III) Orca
(IV) Savvy Navvy

Without this context it is difficult to assess whether there is any specific issue with Navionics updates, as you imply. Also one location and one change, though important for locals, does not prove a general trend. One would need to look at a wider area (as the RIN work tried to do).

 

[doug748]

Thank you all

I believe my Tacktick gear from circa 2013 is NMEA 0183, so the Onwa could definitely be a good optin. Have reached out to the well recommended UK supplier, and will see what response I get.

I find above the companionway the best mounting spot, you are naturally looking that way and it is directly in your line of sight. Plotters always struggle in bright light so a sprayhood gives some useful shade as well as protection from the elements and random ropes. As you are blessed with a tiller you will also often be seated towards the front of the cockpit, quite within range.
.....Just saying that you may find a small sprayhood could be a great blessing on your proposed longer trips, not least the protection it gives from wind blast and boost to a limited accommodation.

Flush bulkhead mounting involves cutting holes in your lovely boat which, if you keep the boat long enough, you will always regret. Selling the boat passes the regret on to the next owner.

.

 

[ashtead]

You could mount below and pair with a cheap ipad or android etc which you load separately with Navionics. Then you have a back up plotter if you main one fails plus you might find the portability of the iPad/ device useful at home or in pub etc.

 

[tillergirl]

I have no intent of identifying the current defects. If I did so, Navionics would be alerted and we would not understand Navionics' usual procedures.

Where Navionics failed that update in over a year, C-Map did (and several other changes in other places) very promptly. I am afraid I am a pensioner and I spend any spare cash on amateur surveys rather than buying Lighthouse, Orca or Savvy Navvy. But I do use current UKHO echarts and paper charts.

I did not assist with RIN - yes I did pre-conference try to correct their understanding of how the Deben is treated. UKHO charts do not display buoyage there save for the Haven Safe Water buoy which is seldom moved and the marginal note says quite clearly "Entry is not recommended without extensive local knowledge (my emphasis). Assistance with transit may be available; contact the Harbour Master at Felixstowe Ferry." The UKHO know that keeping a SNC at that sort of scale is impossible - next week could change - and they also know that the locals (who can be seen on the ECF), ECP and Trinity House have worked out a way of providing the very latest information. You might be interested in Navionics view of the marginal note at the Deben? "Woodbridge Haven is dangerous in strong onshore winds especially on the ebb which runs very strongly out of the rivers (sic) at springs. The buoys and beacons are moved to meet frequent changes in the positions of the channels" further "At Woodbridge Haven the rear leading beacon is red. The front beacon red with a white triangle. The beacons may be lit in an emergency" - Really?

I know that to criticise Navionics is a very unpopular thing to do but I suspect that I am the only person in the world who has been monitors Navinoics daily - it is a rather tedious business. And it is a dismal business when for example you refer back to a change of depth reported by the UKHO back on 4th November. A typical notice which says "At position, insert depth 'x', delete depth 'y' close NW". And yet when you go to Navionics in November, or December, or January or February, or March today and you cannot even find the depth 'y' to delete because the depth in that location is 3 metres different! At least C-Map had the old' depth!

Your final sentence is interesting. I did speak to an organiser of the RIN conference and offered to make a video of my evidence - after all the documentary evidence already comprised over 100 pages and it is a visual business. But it was quite clear that there was no interest. They could have assessed the evidence.

 

[JesseLoynes]

I've added a photo below for ease of description. In reply to a couple of the useful suggesitons above:

- There's not much of a companionway, and the it gets a long way forward of the helm position.
- I have wondered about a sprayhood of some design, but space is tight between coachroof and kicker, so unlikely to happen.
- I've marked the likely locations with the blue shading, probably starboard side. (Throttle controls are in the coaming upstand on stbd side in way of tiller.
- I'm fortunate that I can live with cutting holes in the boat - I've built it once, I can repair the hole if necessary.

Guess the photo also shows why paper charts in the cokpit are tricky... so the paperwork will stay below, and we'll have the electronic view in the cockpit.

Jesse.