Wednesday, 23 May 2018
Pelagia's Summer cruise has begun. We are now in the Desolation Sound area for 4-6 days. Days are sunny and warm (mid 20s) and anchorages empty... wonderful!
Looking like big Westerlies in Johnstone Strait (reaching gale force) are due to switch to SE on the weekend. Likely we'll aim for then.
Wednesday, 16 May 2018
|More than a year after chart update available, Navionics and C-MAP charts still missing CHS Coward's Cove data|
In preparation for our cruise to Haida Gwaii this Summer, we are updating our Canadian Hydrographic Service (CHS) charts. We are also comparing them to the C-MAP and Navionics commercial charts we use on our chartplotter (C-MAP) and occasionally on our Android (Navionics).
We are finding the commercial charts do not include all updates provided by CHS. [A CHS chart subscription allows regular updating (at least monthly) for 24 months.] For example, CHS chart #3980 was revised in January 2017, with substantial additional survey information for the Kitasu Bay area (Swindle Island/Laredo Sound). As of May 2018, neither C-MAP nor Navionics included this information.
The charts above show the Navionics, C-MAP and CHS chart information (at a display zoom showing the maximum information available*) for "Coward's Cove" (unofficial name) at the northern portion of Kitasu Bay. It is a good anchorage after passing through Meyer's Passage; we anchored here in 2007 when no CHS survey information was available. Although still sparsely surveyed, the current CHS chart now provides enough information to make one feel comfortable entering the cove. (Kevin Monahan of Shipwright Productions produced a chartlet including Coward's Cove in the 1990s.) Neither C-MAP nor Navionics provides any information on depths or hazards in this cove.
Cann Inlet is close by (to the east of) Coward's Cove. The outer half of this inlet is well-surveyed in the 2017 CHS chart (the inner half remains "unsurveyed"). As with Coward's Cove, neither C-MAP nor Navionics show the detailed depth and hazards information provided by the CHS chart (indeed, they show essentially no information).
|More than a year after chart update available, Navionics and C-MAP charts still missing CHS Cann Inlet data|
C-MAP and Navionics charts covering the British Columbia coast are much less expensive that the equivalent set of CHS raster charts. (Indeed, Navionics and C-MAP charts for iPad and Android are inexpensive.) However, as the above demonstrates, these commercial charts do not necessarily keep up-to-date with CHS charts and surveys.
Our boat Pelagia's safety (and ours) is worth paying the higher price of official CHS charts.
In practice, we use the C-MAP charts on our cockpit chartplotter, but double check these with updated CHS raster charts (which we often run simultaneously on Android at the helm).
* Navionics (and to a lesser extent, C-MAP) offers chart views with additional depth information ("Sonar Charts"). In many cases, this increased "detail" appears to simply be an interpolation between surveyed depths (i.e., not real depth data). In places with sparse depth surveys, these interpolations are at best, guesses. In other cases, the increased detail may derive from community-derived (crowd-sourced) depth information. It is not made clear where the data comes from. In the latter case, there is no accounting for variables such as tide level, location of depth transducer on hull, accuracy/inaccuracy of transducer calibration, or errors due to sea bed (e.g., weed or kelp giving erroneous readings). The internet has numerous examples of problems (for example: 1, 2, 3, 4) with these crowd-sourced Navionics Sonar Charts. I wouldn't touch them.
Saturday, 12 May 2018
"Plans" are to head North to Haida Gwaii. We've made our Gwaii Haanas National Park Reserve booking (July), and plan to leave Vancouver May 20th with SV Carousel.
We were last up in Haida Gwaii during the Summer of 2011 (and before that, 2002). Looking forward to returning North.
Of course, sailing plans are written in the sand at low tide....
Friday, 30 March 2018
Environment Canada, Canada's national weather forecaster, provides this detailed, highly informative guide to weather patterns on the B.C. coast, including helpful tips for mariners.
|Sample page covering Kelsey Bay (Johnstone Strait) winds|
It has been "archived", so not all that easy to search for; here is the direct link to the pdf file (click to download): http://publications.gc.ca/collections/collection_2016/eccc/En56-240-3-2015-eng.pdf
IF the above link is broken, use this link to download:
Thursday, 15 March 2018
|Top of Blackcomb's Glacier Chair (March 15, 2018)|
Monday, 12 March 2018
Thursday, 22 February 2018
|North coast of British Columbia: Rocks keep being found, charts are updated, and new chart editions produced|
We've written several posts about electronic nautical charts, especially in Mexico, and have noted that commercial charts, such as Navionics, are not always as up-to-date as the official national charts. Returning home to Canada in 2015, it was a relief to be back in well-charted waters.
Well, not always.... But at least Canadian charts are regularly updated, as well as new chart editions being produced.
Pelagia's Furuno chartplotter uses vector charts from C-Map, which we assiduously update each year (at a cost of about C$120/yr). However, we have learned to always compare these vector charts with our Canadian Hydrographic Service (CHS) charts (in raster format), as they are regularly updated (as much as monthly, when required). We also feel less likely to miss a charted hazard on a raster chart compared to a vector chart (learned many years ago, from direct experience unfortunately).
With the excellent CHS charts available here in Canada, it is too easy to become a little less attentive to keeping charts updated. Especially given CHS raster chart packages are pretty pricey (C$522 for all of BC coast). However, their purchase includes two years of chart updates (online), effectively giving one updated charts for three summer cruising seasons. (Sure. It would be nice if CHS would provide our charts for free, as is the case for NOAA charts in the USA. As CHS notes, however, "domestic, fiscal and social policy" is different between the USA and Canada. Yes, indeed. So, given the choice.... ).
Preparing for our cruising this coming Summer (back to Haida Gwaii!), I've started looking into changes in charts since we were last up there in 2011. I'm finding many. New surveys, new charts and, unfortunately, I guess boaters finding rocks. Here are just two examples (in places we are likely to go; see small scale chart above):
Rock in passage between Penrose Island and unnamed island at North end of Klaquaek Channel (Rivers Inlet):
Absent on charts earlier than 2016, somebody must have found this rock the "hard" way (shown by the "+" in the circle, indicating "underwater rock of unknown depth, dangerous to surface navigation").
"New" rocks in Windy Bay, Lyell Island (Haida Gwaii)
I found this update after I read a recent local newspaper report of a charter sailboat (that takes guests on week-long cruises in Gwaii Haanas National Park Reserve) hitting rocks in Windy Bay, a main stop for cruisers in the park. Don't know if this is the rock it hit, but: in place of a 5.8m sounding and kelp (pre-2011), there are now two rocks (one awash at chart datum, and the other drying at 0.4m tide level).
Pelagia is too valuable to us to take chances without having the most up-to-date, official* CHS raster nautical charts. C$522 for 3 years seems a small price to pay for the added security. In practice, we compare our C-MAP and CHS charts in advance and then, in tricky areas, we run both the C-MAP charts on our chartplotter and the CHS raster charts on our Android tablet (with both in the cockpit).**
*Technically, CHS raster navigational charts do not satisfy ECDIS requirements for ships over 100 tons. However, Canadian chart carrying regulations make exceptions for ships under 100 tons, provided they have sufficient "local" knowledge. This includes: the location and character of charted lights buoys, marks, shipping routes, navigational hazards, and prevailing navigational conditions, such as ice, tides, currents, and weather patterns.
** We do have and occasionally use Navionics charts (on our Android tablet). However, we prefer C-MAP vector charts, and even more so the CHS raster charts. We have considerable distrust for "Community Edits", especially when it comes to hazards such as rocks, as well as anchorage suggestions.