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Thursday, 26 May 2016

Finally... out on Pelagia sailing (for a couple of months)

Sailing during VRC Sailpast, May 14, 2016 (photo by Barbara on SV Berkana)

We finally left the dock, with the plan to spend the next 2 months or so cruising North (see previous post for our "plans").  We are currently in Pender Harbour, after a couple nice days/nights in Smuggler's Cove. Weather has been comfortable (~20 deg. C), sometimes sunny other times overcast. Enjoying our new kayaks.

Kayaking around Smuggler's Cove, May, 2016 (Pelagia anchored with stern tie).


Thursday, 19 May 2016

Mexico charts: C-MAP versus NAVONICS

This post provides further information for cruisers considering/planning a cruise to Pacific Mexico. Preceding posts include: (i) Charts, Cruising Guides & Weather Sources for Mexico, (ii) C-MAP vs SEMAR charts, (iii) CM-93 vector charts, and (iv) using Google Earth and GE2KAP to create GPS-accurate GE image "charts"
 

UPDATE March 2022: See new post on "Best chartplotter and chart source for Mexico: OpenCPN & O-CHARTS"

UPDATE 2021(Jan): For the locations noted below, both C-MAP and Navionics now show the same updated details. However, the newer more-detailed SEMAR raster chart (but not included in the SEMAR vector set) for "the islands" in Bahia de la Paz (THE main cruising area for boats out of La Paz, BCS) is missing from CMAP and incorrect for Navionics (I prefer "no data" to "wrong data"!)

The differences noted below in this 2016 post show the kind of differences that can exist (the ones below are now corrected). The only way to know if a commercial chart is updated is to compare to up-to-date SEMAR charts.

 

2016 post:
In a number of preceding posts, we've noted that in some places in Mexico, "up-to-date" Navionics charts lack the updated detail found in "up-to-date" C-MAP charts.

Increased detail in a chart does not guarantee the chart is more "accurate"; however, it likely indicates the chart has added in updates from the official Mexican nautical chart supplier, SEMAR

Below are several examples in the Sea of Cortez (and south to San Blas) where we've found Navionics charts lacking in detail compared to C-MAP charts. Readers may find the opposite in other areas (although we have not seen this).

In the examples below, the C-MAP image is always on top and the Navionics on the bottom. Each is zoomed so that the maximum detail available is shown.





La Palmita anchorage (south of B. Conception):




Loreto:




Altata:




San Blas/B. Matanchen:




Cruisers should use multiple sources of information rather than relying solely on only one commercial chart source (e.g., Navionics or C-MAP). Given the relatively low expense of Navionics and C-MAP electronic charts, especially on IOS and Android platforms, it makes sense to use both (as well as charts from CM93, GE-image, Blue Latitude Press, and, if you have them, SEMAR).

Importantly, as we have seen up in BC waters, commercial charts such as Navionics and C-Map are often not up-to-date with official chart sources (and may take months to over a year to include an update).

Both Navionics and Jeppesen/C-MAP provide methods to report a "Cartography Discrepancy". However, these require some work to submit, and for large areas where a chart does not include the most up-to-date cartography provided by the official cartography office (in this case, SEMAR), it would seem the responsibility of the electronic chart provider to keep their charts for sale to the public up-to-date!  

Friday, 6 May 2016

Marine weather forecasts for British Columbia: Sources for band-limited access (e.g., text forecasts for cell phone, HF-SSB/HAM and/or Satellite Phone) [Updated June, 2017]

All of BC Coast (zoom in to view)
Last revised: June 16, 2017 (broken links fixed)
As we prepare to head north to the central coast of British Columbia, we are updating and collating sources for accurate (i.e., Environment Canada) marine weather forecasts, with a particular eye towards obtaining these forecasts using band-limited methods: (i) via High-Frequency Single-Sideband (HF-SSB) radio (Marine band Sailmail and HAM Winlink), and (ii) via pay-per-MB cellular data services.


To SKIP following Introduction, PAGE DOWN  and go DIRECTLY TO BANDLIMITED SOURCES FOR BC WEATHER

Marine forecasts from Environment Canada (as well as land-focused weather forecasts) are available on the web and, importantly, via standard VHF marine weather stations throughout most of the British Columbia coast. The images above provide an overview of the forecast regions (titles in red), names/locations of shore-based weather stations, and names/locations of ODAS weather buoys. The image below below zooms in on the "Georgia Basin".

Georgia Basin

Mariners new to BC waters are recommended to download Environment Canada's summary/explanation of marine forecasts for British Columbia waters:  available as a pdf here.

A very detailed description of BC marine weather is found here: http://www.publications.gc.ca/site/eng/9.630051/publication.html, available only as a 5 MB pdf download (The online HTML version is no longer available.).  IF this link is broken, download file from here:
https://drive.google.com/open?id=12e12WMP7GlHqbyHkBoayfXxxEnBVjfVR

ENVIRONMENT CANADA MARINE FORECASTS VIA WEB -- when bandwidth not a concern
When good access to the internet is available, mariners can obtain detailed marine forecasts from Environment Canada using their web browser-- note, these websites can eat up cellular data

South Coast -- Georgia Basin (Straits of Juan de Fuca up to Johnstone Strait/Estevan Point):
URL: http://weather.gc.ca/marine/region_e.html?mapID=03

South Coast (includes Georgia Basin, all of Vancouver Island, central BC coast up to McInnes Island)
URL: http://weather.gc.ca/marine/region_e.html?mapID=02

North Coast  (North end of Vancouver Island to Alaskan border)
URL: http://weather.gc.ca/marine/region_e.html?mapID=01

One issue with viewing forecasts from the web is that one typically does not retain a copy of the forecast as one switches between webpages, unless one intentionally makes a copy of the forecast. This makes it difficult to review forecasts.  The text-based forecasts (for bandwidth-limited methods) discussed below provide methods to retain these forecasts for later review.


ENVIRONMENT CANADA MARINE FORECASTS VIA VHF MARINE RADIO
Importantly, marine forecasts from Environment Canada (as well as land-focused weather forecasts) are available via standard VHF radio marine weather stations throughout most of the British Columbia coast. The VHF weather channels and regions are indicated in the images above. Due to British Columbia's complex topography, with its high mountains, deep fjords, and thousands of islands, which specific channel to use for any given bay/cove is not always obvious. The images above are helpful, but the best method is simply to try multiple channels.^ 

However, there are isolated areas where these forecasts can be difficult to obtain via VHF radio (either non-existent or very broken up), such as deep in the many fjords of the BC coast and Vancouver Island (Princess Louisa Inlet and Vancouver Island's Kyuquot inlets, for example, have NO VHF weather). Moreover, these VHF broadcasts can be problematic for weather planning as (i) although repeating, if one misses a region, it takes a while to hear it repeated, (ii) it can be difficult to keep track of/recall of the many forecasts given over the VHF radio (here is where making an audio recording of the forecast could be helpful), and (iii) the forecasts available for a given area may not include a region one is planning to cruise to in a few days. The text-based forecasts (for bandwidth-limited methods) discussed below provide methods to solve these issues.

^In addition to marine weather channels, there are also public weatherradio channels on marine VHF (and/or AM or FM radio). These channels provide weather for shore-based areas in both English and French and also repeat marine weather forecasts. For frequencies, see http://www.ec.gc.ca/meteo-weather/default.asp?lang=En&n=770985EF-1

BANDLIMITED OPTIONS FOR WEATHER FORECASTS:

Why do we need "bandlimited" (small data size) options?

* Bandlimited weather forecasts can be downloaded very quickly.  


* Bandlimited weather forecasts incur little data cost for services that charge per MB (cell data, satellite).  



  • Internet access (via WiFi) is often very slow and/or "spotty" (cuts in/out). This is the case for WiFi in many marinas. [Note: a Wifi amplifier is very helpful. This could be more-expensive options such as the Wirie (at least US$400), the better-priced Wave RV Marine (US$169), or the many inexpensive Wifi "range extenders/amplifiers" available from online sources such as Amazon.)
  • Internet/data access costly (priced in $/MB) -- this is especially the case with cell phone data plans
  • Internet not accessible: no WiFi and no cell phone coverage. This is the case for most British Columbia waters. In these cases, one relies on to audio forecasts on marine VHF radio.
  • Alternatively, one can obtain forecasts anywhere/everywhere via HF-SSB ("shortwave") Radio and Pactor Modem  or satellite transceiver such as Iridium GO!  However, access to weather forecasts by both HF-SSB Radio/Pactor Modem and satellite transceivers are limited by (relatively) slow data speeds (before data compression: <2400 BAUD for Pactor3; <5512 BAUD for Pactor4;  ~2400 BAUD for satellite services). Satellite services are (usually) further limited by data cost (although there is a US$159/month "unlimited" data plan for Iridium GO!).
How does one access bandlimited weather forecasts?
  • HF-SSB/Pactor or Satellite service: send request ("query") to "Saildocs" via email service (e.g., HAM-based "Winlink" email*, often using "AIRMAIL" program, Sailmail-based email# using "AIRMAIL" program, Satellite-based system using Sailmail or other system. Send text-only email to Saildocs, then 1-2 minutes later to see text forecast
             * Winlink email service free and unlimited (no "business" use); however, requires HAM radio license 
             # Sailmail email service US$250/yr; requires marine radio "station license"; limited to 90 minutes connection/week
  • WiFi internet/cell data plan: using your email service, send request to Saildocs, same as above 
  • WiFi internet/cell data plan: go to the specified URL (e.g.,http://weather.gc.ca/marine/marine_bulletins_e.html?Bulletin=fqcn13.cwvr). (Remember to save the displayed forecast)
  • GRIB-file computer-generated weather forecasts: send "grib" request to Saildocs, as described below

Saildocs:  (From the Saildocs website) Internet services for the bandwidth-impaired. Saildocs is an email-based document-retrieval system for the delivery of text-based Internet documents either on request or by subscription. Saildocs can deliver web pages (including text weather forecasts, and provides subscriptions for automatic delivery. Additionally Saildocs provides custom grib weather-data files per request from data downloaded from NOAA/NCEP and other sources.  Saildocs offers text-based document retrieval and subscription services for offshore sailors, adventurers, missionaries and others who must somehow live their lives without fiber, DSL or even 56Kbaud dialup connections. There are currently two services offered, a document retrieval service which will return documents from the Internet or our own files, and a subscription service which will send Internet documents (for example weather reports) at scheduled intervals.

Saildocs can also fetch documents from the web and convert them to plain text. This often results in a little extra (and irrelevant) text added before/after the information (forecasts) of interest, but it rarely adds much in terms of datasize or download time. 

The services provided by Saidocs are free and open to anyone -- one does not need a HF-SSB radio or satellite system to use Saildocs.

For full information, go to http://www.saildocs.com/info or send an email as follows:
To: query@saildocs.com
Subject: (anything you want)
send info
send index


Saildocs also has short versions of request for text forecasts. Oddly, the "send xxxxx" command doesn't always correspond to the Environment Canada file name. The list below provides these short commands, which were tested as of April 2016 (short commands tested denoted by "+").

==============================================================================================
skip to here...

BRITISH COLUMBIA WEATHER FORECASTS: BANDLIMITED OPTIONS

The following provides URLs for web and Saildocs access to Environment Canada's text-based forecasts. In some cases, Saildocs has a shortened command to receive these files.&

Environment Canada's forecasts all involve expert human (meteorologist) interpretation and modification of computer-generated forecasts. In most cases, these forecasts take into account complicated shore effects (something which strictly computer-model based forecasts -- such as GRIB files -- do not provide).

& USA-based NOAA also provides access to all  Environment Canada text weather forecasts using its FTP server: see http://tgftp.nws.noaa.gov/ftpmail.txt. These may be accessed by sending URL to Saildocs or by direct ftp request to NOAA ftp server. (In 2016/2017: NOAA discontinued direct web access to its FTP server.)


BRITISH COLUMBIA MARINE FORECASTS
 
Marine Forecasts (Days 1 & 2) for the ALL British Columbia waters
Text file: FQCN13.CWVR
URL:
http://weather.gc.ca/marine/marine_bulletins_e.html?Bulletin=fqcn13.cwvr
Saildocs: send http://weather.gc.ca/marine/marine_bulletins_e.html?Bulletin=fqcn13.cwvr
+Saildocs (short version): send fpcn20.cwvr

Extended Marine Forecasts  (Days 3, 4 & 5) for ALL British Columbia waters
Text file: FQCN53.CWVR
URL: http://weather.gc.ca/marine/marine_bulletins_e.html?Bulletin=fqcn53.cwvr
Saildocs: send http://weather.gc.ca/marine/marine_bulletins_e.html?Bulletin=fqcn53.cwvr
+Saildocs (short version): send fpcn54.cwvr

Wave Height Forecasts (Days 1 & 2) for the Pacific waters (i.e., areas exposed to open Pacific waters)
Text file: QCN23.CWVR
URL: http://weather.gc.ca/marine/marine_bulletins_e.html?Bulletin=fqcn23.cwvr
Saildocs: send http://weather.gc.ca/marine/marine_bulletins_e.html?Bulletin=fqcn23.cwvr

"Marine Synopsis" and "Marine Weather Statement" for Pacific Waters   (Provides a general picture of the position and motion of the main weather features (lows, highs, fronts).
Text file: FQCN10.CWVR
URL: http://weather.gc.ca/marine/marine_bulletins_e.html?Bulletin=fqcn10.cwvr
Sailmail: send http://weather.gc.ca/marine/marine_bulletins_e.html?Bulletin=fqcn10.cwvr


BRITISH COLUMBIA FORECASTS FOR SHORE LOCATIONS
(focus on land-based weather priorities, including temperatures, sun/cloud/rain; not mariner-focused but still very much of interest)

Shore forecasts for the south coast of British Columbia (Days 1 & 2)
Text file: FPCN11.CWVR
URL: http://weather.gc.ca/forecast/public_bulletins_e.html?Bulletin=fpcn11.cwvr
Saildocs: send: http://weather.gc.ca/forecast/public_bulletins_e.html?Bulletin=fpcn11.cwvr


Shore extended forecasts for (ALL) coastal British Columbia (Days 3, 4, 5, 6 ,7)
Text file: FPCN50.CWVR
URL: http://weather.gc.ca/forecast/public_bulletins_e.html?Bulletin=fpcn50.cwvr
Saildocs: send http://weather.gc.ca/forecast/public_bulletins_e.html?Bulletin=fpcn50.cwvr

Shore forecasts for the central and north coast of British Columbia (Days 1 & 2)
Text file: FPCN12.CWVR
URL: http://weather.gc.ca/forecast/public_bulletins_e.html?Bulletin=fpcn12.cwvr
Saildocs: send http://weather.gc.ca/forecast/public_bulletins_e.html?Bulletin=fpcn12.cwvr
+Saildocs (short version): send fpcn11.cyxy



BRITISH COLUMBIA: CURRENT MARINE OBSERVATIONS 
(e.g., wind speed/direction, temperatures, wave heights, etc)

The easiest method is to get the "Regional Summaries", which provide (when available) in the following order:

Wind(knots)     Wave height(m)     Wave period(s)     Pressure(kPa)     Air temp(°C)     Water temp(°C)

Note: the translation by Saildocs of these regional summaries is a little garbled but still quite readable, provided one keeps in mind the above order of values.

Regional summary: South Coast
URL: http://weather.gc.ca/marine/weatherConditions-regionalSummary_e.html?mapID=02&siteID=06400&stationID=VTF
Saildocs: send http://weather.gc.ca/marine/weatherConditions-regionalSummary_e.html?mapID=02&siteID=06400&stationID=VTF

Regional summary: North Coast
URL: http://weather.gc.ca/marine/weatherConditions-regionalSummary_e.html?mapID=01&siteID=03407&stationID=46183
Saildocs: send http://weather.gc.ca/marine/weatherConditions-regionalSummary_e.html?mapID=01&siteID=03407&stationID=46183

Regional summary: West Coast Vancouver Island
URL: http://weather.gc.ca/marine/weatherConditions-regionalSummary_e.html?mapID=02&siteID=15300&stationID=WFG
Saildocs: send http://weather.gc.ca/marine/weatherConditions-regionalSummary_e.html?mapID=02&siteID=15300&stationID=WFG



Reports from all staffed "Lightstations" (lighthouses) in British Columbia (South & North Coast)
These reports are provided by the lighthouse keepers, and include observations about visibility, cloud cover, fog, and seas.  These reports are somewhat coded using abbreviations -- for details, see http://www.ec.gc.ca/meteo-weather/default.asp?lang=En&n=3D8459C9-1

URL: http://weather.gc.ca/marine/weatherConditions-lightstation_e.html?mapID=02&siteID=06400
Saildocs: send http://weather.gc.ca/marine/weatherConditions-lightstation_e.html?mapID=02&siteID=06400



GRIB FILE FOR BC COAST FROM SAILDOCS
(from Saildocs)Grib files are computer-generated forecast files from a NCEP/NOAA computer, which are sent without review, and are offered on an as-is basis. There is no assurance that the data is available, accurate or correct. Both Saildocs and the computer model itself are automated systems, subject to a variety of failures and errors. Grib files do not indicate the very-complicated shore effects that occur in BC's waters -- for details, see https://www.ec.gc.ca/meteo-weather/default.asp?lang=En&n=7C8C8223-1   such as  (for example): Summer inflow/outflow winds in fjords, Winter "Squamish" outflow winds in fjords such as Howe Sound, gap winds such as "Qualicums", katabatic (williwaws) winds down mountain slopes, and "corner winds" produced near large capes/points (the worst being winds around Brooks Peninsula).


For information on obtaining GRIB files from saildocs, see: http://www.saildocs.com/gribinfo

To view the grib file, one needs a grib-file viewer. See:  http://weather.mailasail.com/Franks-Weather/Grib-File-Viewers   OpenCPN can be used to view grib files, overlaid on charts.


  • To obtain a small grib file (every 2 degrees, filesize = 11 KB) for the British Columbia coast, with forecast for every 6 hours out to 72 hours, send the following to Saildocs:
To: query@saildocs.com
Subject: anything you want
send GFS:56N,46N,144W,122W|2,2|0,6..72|PRMSL,WIND,WAVES,RAIN
  • The above request results in a low-detailed GRIB file. To obtain a GRIB file with maximum detail (every 0.5 degrees), send the following request:                    (Note: file size is 76 KB!)
send GFS:56N,46N,144W,122W|0.5,0.5|0,6..72|PRMSL,WIND,WAVES,RAIN
  • To expand the area covered in order to get the "big picture" for weather (e.g., to all of Northeast Pacific ocean), change the Lat/Long. (Note: set detail to 2,2 degrees, otherwise file size will be too large.)