Notice of severe shoaling

For those cruising north to Alaska. This place is northwest of Petersburg.


Uncharted shoaling was observed in Francis Anchorage on February 14th, 2019 in position 57°08.95’N, 133°10.03’W. The charted depth for
this location is 15 fathoms and the observed depths rapidly shallowed from 120 feet and ranged from 8 to 10 feet. The navigational charts for
Francis Anchorage are based on pre-1900 Partial Bottom Coverage Surveys and in 1976 ‘shoaling to bare’ was reported further into the
anchorage. Mariners should transit this area with extreme caution and be aware of areas that may not be adequately charted.
Questions/concerns should be directed to Todd Buck with the Coast Guard District 17 Waterways Management Office at (907) 463-2269 or by
email to todd.r.buck@uscg.mil.

ASD,

My NOAA vector chart in Coastal Explorer shows a shoal coming up to 7 feet at that same lat/long. I wonder who discovered the uncharted shoal.

Tom

You can report chart errors. I've done it several times. You need good nav info and in reporting depths, take into account the tide, details of your sounding device and transducer mounting depth, type of vessel, etc.

https://www.nauticalcharts.noaa.gov/customer-service/assist/

That whole shoreline is a very abrupt shelf, and a long shallow flat to shore. Farragut Farm is back in there, and the only way in and out is paddling up the estuary at high tide. The edge of flats like that are often only approximations on the charts.


A more exciting surprise is in the small cove NW of the spot in the notice. The chart shows a rock pile in the inter tidal zone, but it turns out that extends all the way out to the 3 fathom line, and dries at low tide. I circled an area to anchor there and never saw less that 75' of depth. Dropped the hook, and as the tide went out, this rock shoal appeared no more than a boat length from where I circled.


Off the well worn paths in AK (everywhere, actually) it's important to pay attention to the date of the survey data that the chart is based on. This is printed on the raster charts, and probably available in the vector charts, but I'm not sure where. Here is the legend for Farragut and surrounding area. The area in question is charted based on a pre-1900 partial survey, so accuracy shouldn't be expected.

Anchoring in Francis Anchorage can be difficult at times due to the number of crab pots. New shoaling adds another layer to the problem.

Speaking of Farragut Farm. If you are in Petersburg when the Farmer's Market is happening, be sure and stop by. Bo and Marja are two of our favorite people and grow the best vegies in the world! While not Certified Organic, they are grown organically. Their operation in Farragut Bay is impressive! Unfortunately, they are usually so busy in the summer they are unable to give tours. If you happen to see a small white homemade trimaran transiting between Farragut and Petersburg, it is Bo and Marja delivering vegies. Google Farragut Farm to learn more.

Tator

Wow, I had no idea about Farragut Farm. Very cool!