On Fri, 26 Sep 2008 19:45:57 GMT, Jere Lull wrote:

Has anyone seen a project to collect position and depth data
automatically and periodically upload the data to a central server?

I was talking to a friend of mine the other day who is a member of the
US Power Squadron organization. Apparently his local chapter here in
SWFL does that sort of thing from time to time. I don't know how the
data is passed along and/or updated.

There is more to it than meets the eye. Each boat needs to have the
sounder precisely calibrated and the state of the tide needs to be
carefully noted.