Monday, 7 June 2021

"UPDATED" NAVIONICS AND C-MAP CHARTS ARE NOT ALWAYS "UP-TO-DATE" (Canada)

You may think (hope) that your just "updated" Navionics or C-MAP charts  are now "up-to-date". This is not necessarily the case (applies to both app and card-based updates).

Recently, checking "Notices to Mariners" (NOTMAR: https://www.notmar.gc.ca/monthly-mensuel-en.php) by Canadian Hydrographic Services (CHS), I noticed the February version indicated newly discovered rocks/shallows in the general area near Discovery Islands and Desolation Sound.

Below are images from official CHS Raster charts from May 2020 and June 2021:

The updated CHS charts (June, 2021) show the two new drying rocks in Manson Passage (top, right) and the 0.3m shallows in Plunger Pass (bottom, right). Both are dangerous to most boats (especially the shallow area in Plunger Pass, which we passed through last summer).

 

What about Navionics and C-MAP? As of June 7, 2021, neither show these updates. This includes the C-MAP App and C-Map SD card (card purchased in May, 2021) as well as the Navionics App (as well as the online viewer).

Manson Passage: Navionics (June, 2021, not accurate)

 
Plunger Passage: Navionics (June, 2021, not accurate)


Manson Passage: C-MAP (June, 2021, not accurate)

Plunger Passage: C-MAP (June, 2021, not accurate)

At least 3 months after CHS issued a NOTMAR about these rocks/shallows, yet they are still not shown on "updated" Navionics or C-MAP charts.

 

IN CONTRAST:

O-Charts (https://www.o-charts.org/) makes CHS ENC Vector charts available for OpenCPN  at a very reasonable annual price (20 Euros for Pacific Coast of Canada). These charts can be updated monthly, and are supposed to be the same as CHS ENC charts. 

(OpenCPN is an excellent free/near-free chartplotter software for Windows, Mac, Linux and Android.)

 

By March, 2021, the O-Charts for Manson and Plunger Passages included the February update:

Manson Passage: O-Charts (March, 2021 -- accurate!)

Plunger Passage: O-Charts (March, 2021 -- accurate!)


Update: just checked earlier NOTMAR editions: current Navionics and C-MAP missing more rocks/shallows in other areas of BC! (O-charts, however, are correctly updated.)


CONCLUSION: Commercial charts such as Navionics or C-MAP may NOT be up-to-date (even though you just "updated" them). "New" rocks and shallows shown on up-to-date official charts may be missing on Navionics and/or C-MAP!

 

On Pelagia, we ensure our CHS charts are up-to-date. Though we also have Navionics and C-MAP, we but put much greater trust on the CHS raster charts (we are still getting used to the O-charts -- so far, so good.)

Monday, 8 March 2021

Saving depths as you go...

 

ERROR NOTE: Fix done (Version 3b) and posted below

This post is part of a series concerning obtaining/creating more-detailed depth information.

Note: this particular post is technical and may not be of interest to some....

 

Entering an unfamiliar (and poorly charted*) bay, it would be nice to have a record of depths as we explore. In such cases, however, one must focus on safely navigating, rather than noting down or saving depths.

* In B.C., many bays and coves on up-to-date, decently charted areas often have only a few soundings.

 

OpenCPN Voyage Data Recorder

Our GPS, AIS, and depth/wind/speed information are now available via WIFI for use by our ship's computer and Android tablet running OpenCPN chartplotting software. OpenCPN is fantastic. Among its many free plugins is the "Voyage Data Recorder", or VDR. When VDR is set to "record", it saves all the NMEA sentence information (including AIS, latitude, longitude, depth, etc) into a text file, until the recording is stopped. A short example of a NMEA text file is shown below:

Sample section of a NMEA text file

In the above sample, !AIVDMs are NMEA sentences for AIS info, $IIDPTs are depths, $IIMWVs are wind, $GPVTGs are speed and course over ground, and $GPRMC, $GPGGA, $GPGLL sentences provide GPS location (Lat/Lon), time, date, course and other GPS information.

The depth information in a NMEA text file does not contain location (Lat/Lon) info. However, there is always such information within less than a second of the depth sentence. We have written a short program to associate NMEA depth info with location, and to save these depth points into two types of files. NMEAtoXYZ is a simple program for Windows PCs that inputs a NMEA text file, and outputs (i) a GPX file of depth waypoints, and (ii) an XYZ file of the same points.  The program gives the user the option to correct depths for tide level (recommended), and to determine the spacing (in time, thus distance) between depths. #

A GPX file can be imported into any GPS or chartplotter. The XYZ file can be used by software to produce satellite image chartfiles WITH depths plotted (see below).

 

The following screenshots show the process and output:

Playback of VDR recording in English Bay. Pelagia is shown as the red boat with a red trail. [The green triangles represent AIS broadcasted from anchored (black dot) and moving (with line of projected course in front) ships.]






Zoom in on Pelagia (with Tug & Tow heading in opposite direction)


 

  

 

 

NMEAtoXYZ-3a: GPX output

Depth waypoints (S2Z22 highlighted) saved to GPX by NMEAtoXYZ program

 

Waypoints are coded in two ways: Arrow symbol and 1st two characters of waypoint name

S2xxxx: Magenta arrow: Depth >20m

S1xxxx: Blue arrow: Depth >2m to 20m

S0xxxx: Red arrow: Depth ≤2M

The symbols are specific to OpenCPN; the waypoint name will work with all GPSs and chartplotters



NMEAtoXYZ-3a: XYZ output

Using SASPLANET and SAT2CHART programs, the XYZ file's depths may be plotted on to a satellite image of the area. This image may then be displayed as a "chart" on OpenCPN. (Full details are explained in SAT2CHART's HELP pages.)

Satellite image chart with depths

The number of depths points plotted by SAT2CHART depend on the zoom factor (higher zooms = more points, when available)

 

One may also plot these depths on (i) an image of a Navionics chart (using SASPLANET & SAT2CHART) or (ii) on an existing raster chart using a GIS program such as QGIS.

 

Depths plotted on CHS chart (using QGIS)

The above examples are from Vancouver Harbour. Obviously, such a well-charted place does not require one to be saving depths and making image charts with depths are not required (it's just a test example).

However...

British Columbia still has some areas where nautical charts contain NO depth soundings (for example, parts of the West coast of Haida Gwaii). Even more common, many bays and coves in BC, even in Southern BC, have very limited depth details. A good example is the entrance to Von Donop Inlet/Ha'thayim Marine Park, which we described in a recent post

As we cruise this coming Summer, we hope to obtain more-detailed depth information for the places we visit using (i) the VDR feature of OpenCPN and the above programs, as well as (ii) more-detailed scans using our Deeper Pro+ portable sounder.

 

The NMEAtoXYZ program (with helpfile) is available free to download from the following link (USE AT YOUR OWN RISK!):

Download revised NMEAtoXYZ-3b

                                      

Note, it has only been tested on a PC running Windows (it MAY work on Linux and MacOS, but these have not been tested).  It is a very simple program (written using QB64), currently with no GUI.  NMEA VDR file plugin and OpenCPN are available for most platforms, except those running iOS. 


# FYI: Reefmaster is commercial software (US$200) that also will save depths with lat/lon, plus a lot more.

Sunday, 16 August 2020

That ROCK in the entrance to HA'THAYIM (VON DONOP) MARINE PARK... Detailed info (UPDATED!)

Depths (in feet, uncorrected for tide)

UPDATE May 17, 2021: CHS "nonnavigational" soundings ("NONNA10") indicate the depth over "the rock" is 0.6m at zero tide. ALSO, the rock immediately north has a least depth of 1.8m. This too would be an issue for boats with a 6' draft (e.g., Pelagia). Text below has been revised.

**Take home: Subtract 0.5m (1.64') from soundings to be safe(r)**

Updated March 14, 2021:

Von Donop Inlet (properly known as Ha'thayim Marine Park) is a favourite anchorage of ours in the Desolation Sound/Discovery Islands area, situated at the northern end of Cortes Island.

As every decent cruising guidebook notes, the narrow entrance has a rock approximately mid channel; the exact depth of this "rock" is not well documented (the official chart shows a "+", indicating a rock "with less than 6 feet over it a zero tide"). Usual navigation instructions are to "hug the western shore". How close to this shore, however, is an issue, as at some tide levels, depths are also too shallow if one hugs the shore a little too closely!

Every year, sailboats hit this rock. Fortunately, we have not, but we know some who have. 

The official CHS chart is not very highly detailed (commercial charts, such as Navionics, derive their data from the CHS chart). We do not depend on the chart for the rock's location, as we have found the "+" symbol to be only approximately correct. Instead, in the past we hugged the western shore when we were passing the "second yellow bare patch on the eastern shore". It always worked for us, but was never a very satisfactory method as (i) hugging the western shore had depths going very low, and (ii) it doesn't really let us know where the rock is located.

This year, David used his new Deeper Pro+ portable sonar to do a detailed scan of the entrance channel (at higher tide) in order to finally figure out this rock.

What we learned:

  • the "rock" is actually a pretty wide rock, least depth of about 1.0 m (3.28') 0.6m (1.9') at zero tide, covering 2/3rd of the width of the channel. A serious issue for most sailboats, and some powerboats
  • there is, indeed, a deep (enough) channel to the west of this rock
  • there is another rock immediately northwest of the rock with a least depth of about 1.9 m (~6.2':  1.85m (~6.06'): so only a worry for boats with keels 6 over feet)
  • further north, there is a very shallow area on the west shore jutting out a little, north of these rocks. Hugging the west shore therefore not a good idea at the northern entrance to the narrow section 
  • do not consider going to the east of the rock (i.e., don't go along the eastern shore)

 

The following figures provide more detailed information:

 

Uncorrected depths in ft: the arrow points to place of 1m 0.6m corrected depth (sorry, not "3.8ft")

 

The Deeper Pro+ sonar app creates a bathymetric map as you scan. The above map was created from many passes up/down/across the narrow section. These passes did not include all of the area within the map (see figures below); the Deeper app interpolates/extrapolates from the data to "fill in" the map. (Thus, if I missed a shallow area, the map too may miss this.) I thus tried to concentrate my scans around the rock/shallow areas to improve accuracy.

 

Unfortunately, the Deeper app does not provide for a correction for tide level -- seems it only understands "lakes" -- so the depths in this map reflect the higher tide level at which I scanned; they must be corrected for tide level (thus, the "8.2 feet" above is actually <4 feet at low tide).

Some extra detail (sorry... ): If one uploads the Deeper Pro+ scan data to the Deeper cloud on the internet (each Deeper owner gets an account), one can login into their account on the Deeper Lakebook page (maps.fishdeeper.com) and view more detailed data, including the actual depth readings. One can also download all the depth recordings, their latitude/longitude. and time as a CSV text file. Of course, none of these depths are corrected for tide level.

[As much as I like the Deeper system, requiring one to have good internet access in order to get the accurate location information -- i.e., the lat/long -- is a serious flaw and ridiculous. Most of British Columbia's coastline is without internet access, even by cell (assuming one would want to use up all your cell data doing this). I had to wait until we stayed in a marina weeks later to upload then download the detailed data.]

After downloading the detailed data into a CSV textfile, I reviewed the Redonda Bay tide data (obtained using a tide app based on XTIDES; inaccuracies can occur), and used Excel to correct the depths to zero tide ("datum"). I then converted a CSV text file of these data to a GPX file using GPSU Import File Converter and then GPS Utility, both available from Alan Murphy's https://www.gpsu.co.uk/.  Note: these corrections are not official; it is safest to assume they could err by 0.5m.

The depth data included 747 soundings... far too many. I decided to reduce the data to (i) depth less than 2m (6.6 feet) as well as (ii) a "safe" route for most boats (unless your boat draws 8 feet!). These data are plotted on a geo-referenced satellite image of the narrows.

As shown below, I converted image to a kap chartfile (which can be read by most charting software, but not onboard dedicated chartplotters), and saved the <2m waypoints and safe route into a GPX file (which CAN be read by most dedicated chartplotters, after conversion, as well as most charting software).  For those wishing to download, see below.

 

 

Note the "+" on the CHS chart is a little north of the actual rocks. The blue line indicate the "safe" route (for Pelagia, at least). 

UPDATE (March, 2021): Paul Higgins has updated his excellent SAT2CHART program to now input depths (in the form of a XYZ file). Below is screenshot of a MBTILES (better than kap) file:

MBTILES file with subset of depths added (in metres). Safe route in blue. Yellow depths are <2m

Now, I have to go kick myself for providing information that makes it easier to enter Von Donop and perhaps increasing the summer crowds. Just kidding! (Although VonDonop is indeed very crowded in July/August!) 

Hopefully this detailed information make entry/exit safer for all. For added safety, subtract 0.5m from the depths to account for possible errors in tide-level correction.

Nevertheless, even with this detailed information, we still go very slow by the rock... one never knows what's lurking below.

Stay safe!


CLICK HERE (updated Mar 14, 2021) to download from Google Drive, the zip file containing the above information, including:

  • Detailed description and instructions, as well as caveats
  • geo-referenced satellite image kap file
  • geo-referenced satellite image MBTILES file, WITH DEPTHS (in metres)
  • GPX file containing <2m depth waypoints and "safe" route waypoints

NOTE: Use at your own risk; there are no guarantees these will be safe for you.

Sunday, 9 August 2020

Sailing home... summer cruise completed

Closehauled, sailing past Howe Sound (smoggy Vancouver in the distance)


We ended-up spending another 10 days in the Desolation Sound area. Enjoying sunny, warm/hot weather and good swimming in the ocean (19-24°C). But it was now definitely crowded; perhaps about 2/3 to 3/4 as busy as a normal summer crowd (no USA boats), but still crowded. We enjoyed more socializing with SV Chanter's Wayne and Lee, as well as with Roly from MV Tropic Isle. Still, we decided we'd hung out enough, and it was now time to leave the crowds and get home to Whistler.

 

Seagulls physically distancing... (these logs are why we try not to sail in the dark in BC)

We had a long but smooth motor down to Pender Harbour. Normally, we stay at the VRC outstation, but it was full (as we said, places are now crowded). Instead of anchoring in Garden Bay, with its many other anchored boats, we decided to anchor in uncrowded Gerrans Bay. Big mistake! Until darkness came, we were continuously rocked by wakes of boats roaring by, including personal watercraft (non affectionately referred to by some, us included, as "sea lice") roaring around towing people. Pender Harbour is easily the most obnoxious anchorage we've ever been to (although Tofino ranks up there): no one gives a second thought to their wakes. 

We headed home with a 5-15 knot Southeasterly predicted. We hoped we might get a sail home, albeit an upwind closehauled sail. As it turned out, we sailed 21 nm, about half the distance, with the winds mostly SE 12-15 kn, closehauled with a reef in the main. Seas also built, especially when against the tide. Lots of green water over the deck. A fun raucous sail home! 

We arrived to our home berth at the Vancouver Rowing Club in Stanley Park near low tide, with only 1-2 feet under our keel. A tight fit with no space for a wide turn (too shallow, but at least all mud), we were lucky this day and came in slowly with no incident. It was hot at the docks. Later, we had a couple family members over for a fun reunion dinner of barbecued burgers.

Next day, while Michelle packed up Pelagia, David caught the Epic Rides bus up to Whistler to get our car and then drove back down to the boat. We arrived home to (busy!) Whistler by dinner time.

An interesting cruise; 760 nm overall.  Much good (socializing within our bubble with Chanter and Carousel, plus Roly; new anchorages; much wildlife; near-empty anchorages in June and in the Broughtons) but some not so good (very so-so weather with rain in June and early July; windlass motor, etc).

 



Tuesday, 28 July 2020

Back down to Desolation Sound area...

Huaskin Lake... easily accessed from Turnbull Cove

Weather in the Broughtons improved somewhat (it's all relative... highs were never more than 15°C), so we kept exploring, including Joe Cove (new to us, as was Monday Anchorage), Waddington Bay, Cullen Harbour, and Turnbull Cove. Sadly, our cruising buddies Gillian and David on SV Carousel decided to head back south after Waddington Bay (our social "bubble" burst, decreasing to 4).


Turnbull was new to us. An excellent anchorage (and not crowded this year), its cold water was chocolate brown from nearby streams. But it held a treat: a 10-minute hike uphill brings one to Huaskin Lake, with a convenient dock and ladder for swimming. Surprisingly, the water temperature was quite comfortable for a swim. We also enjoyed socializing with friends Wayne and Lee on SV Chanter (part of our original 6-person social "bubble").


Turnbull Cove was technically the furthest north we would go this year, but we did venture further west to Blunden Harbour. Blunden is a favourite, but this time we got to endure 12 hours of winds, gusting to 27 knots. Fortunately, there was plenty of space and good holding (mud), so we didn't budge. Still, never "fun".


We then headed across to Port McNeill to reprovision, opting to stay 2 nights to be more relaxed. Besides, Port McNeill deserves it, being so welcoming during these COVID-19 times (in contrast with Sointula, which we normally prefer, but we skipped this year as they are not being so "open" to visiting boaters).


After McNeill, we headed back into the Broughtons, staying a night behind Dead Point, which had too many commercial crab traps (far too common an issue in the area) but was nice and quiet (we were solo). Then we rejoined Chanter in Port Harvey, with a plan to head down Johnstone Strait in the early morning.


After our slow trip bucking the flood tide coming up Johnstone 3 weeks earlier, we were worried going in the morning when the ebb was in play would again be a problem. It wasn't. We had a great sail down Johnstone Strait, then Sunderland Channel. We temporarily anchored for lunch (KD time on Pelagia) waiting for Whirlpool Rapids to quiet down, then sailed again up Chancellor Channel, all the way to Greene Point rapids (where we reached 11 knots going with the flood). Altogether, we sailed half the distance. A good day, with our hydrovane Finn doing a great job.


A night anchored in Cordero Islands (and dinner with Chanter), then we headed through the Yaculta Rapids (surprisingly devoid of usual many gin palaces... well, there was one) and down to the Desolation Sound area, to Hathayim/Von Donop Inlet.


Here in Von Donop, the weather has been hot (30°C) and the water warm (20°C) for swimming. Although far busier than the Broughtons (or Von Donop last month) , the 34 boats total on  our first night back are far less than the usual 50-60 boats of normal years. (Indeed, yesterday and today, the numbers have dropped to 15-20 boats.)


We expect to be home no later than August 7-10th. Until then? Plans are flexible.

Saturday, 11 July 2020

To the Broughtons...


SVs Carousel, Pelagia and Chanter anchored in Monday Anchorage
 



After nearly a month in the Desolation Sound/Discovery Islands area, it was time to move on.

Our time in Desolation Sound started with nearly empty anchorages combined with only "warmish" air and (sea) water temperatures (too cold for us to swim). By the end, seas had warmed up so that we were enjoying swimming, there were some sunny days, and the anchorages definitely becoming busy. Not the pre-Covid-19 stupid-busy with 60-80 boats (and often majority American boats), but busy such that we'd see 15-20 (Canadian) boats. Call it "Canadian busy".

So it was time to move on.

We headed to the Broughtons, with hope of empty anchorages, mild bucolic days, and wildlife. We got some of this, including many black bear sightings, a close-up in our kayaks with a wading grizzly bear, and many whale sightings.

Getting to the Broughtons, however, included a real slog bucking the tide in Johnstone Strait (wasn't supposed to be a flood with 5+ knots against us!) that happily ended with a great 9-mile sail (steered by Finn, our windvane).

The weather for the first week in the Broughtons was better than forecasted, allowing for many kayak trips. But never that warm. The past few days, unfortunately, have been soaked with torrential rains and some wind. And the coming week has rainfall predicted every day.
Making us consider returning south (well, actually east) back down Johnstone to Desolation and perhaps home.

But first, we are giving it another try in the northern Broughtons. Currently, we are anchored in "Monday Anchorage" (don't be fooled by its name: Monday is not a good anchorage in windy weather), waiting/hoping for the rain to let up.

We shall see....


Update: the rain did indeed end, in time for drinks in the cockpit before dinner.

Monday, 29 June 2020

Windlass woes (and eventual win)

Windlass motor with broken "up" stub (circled)



 
 

June 16, 2020:

Can't always be fun and games.... 

Windlass problems occur every once in a while (in case you are wondering, the windlass is the equipment we use to raise/lower the anchor). But our problem turned out to be terminal: our positive "up" terminal had sheared off, and this meant the end for the motor. 

Of course, it happened when we had a lot of chain out (230'). Fortunately, back in 2008, we purchased a "manual recovery kit" for the windlass. Unfortunately, it was very hard work for David to bring it all up. Nearing the end, he was sweating hard and taking multiple breather breaks. But up it came. 

We headed to the docks of Refuge Cove, where David removed the motor/gearbox assembly. It did not look good (as we said, it was "terminal"). At least it was easy to remove. 

Next morning, we started making calls. First call was to Ocean Pacific Marine in Campbell River. Using our part number, they said it looked like it would have to be ordered from England. Yikes! We started planning a fast return to our docks in Vancouver. But, 20 minutes later, they us called back, saying there was a new part number and indeed, there was a replacement in Victoria. It was Friday morning and they should be able to get it to Campbell River by Monday "11ish".

Only $2300.... 

After a couple of nights at the dock at Refuge Cove (where we sorted out our backup - - and much lighter -- anchor line), we headed over to Gowlland Harbour (very near Campbell River) to try anchoring without a windlass for a couple of nights. Turned out to be a great anchorage (tons of room with only 1 other boat). Later, using a winch on the mast, we had no problem getting our anchor (with lighter line) up. 

Monday morning, we headed over to the Discovery Marina in Campbell River, where Ocean Pacific Marine was conveniently located. By 1130am, the new windlass motor assembly had arrived. After some concern it was the wrong part (it may have been mislabled... but phone calls to distributor indicated it would only fit properly if it were correct), David installed it (in between torrents of rain). And it worked! 

Next morning, we headed back over to Cortes Island, to Hathayim/Von Donop Marine Park, a favourite of ours. 

A pricey part, but still a "win" since we could do our own repairs, and get back  cruising.