In planning for my trip up the Inside Passage, I'm noting several charted
Magnetic Disturbance Areas. Some are as large as 10 miles across with a
possible disturbance of 7 deg. The largest I note is near/ S.E. of Cape
Northumberland, Duke Is.. This might be encountered while transiting to and
from Ketchikan.

To my knowledge, I have never operated a boat with magnetic compass in such
a disturbance area. I assume that this wouldn't be a problem in clear
weather where visual course keeping might be used. I don't think I would
want to rely on AP set to follow a magnetic heading..

However, would it be appropriate to set a waypoint and allow the GPS steer
through these areas and would this be a safe method at nite or in reduced
visibility..

Opinions welcome.


--
Steve
s/v Good Intentions