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Frank wrote:

> Finally, the practical value of this is not that we can start  calculating
> dip and all the rest based on the specific temperature profile  since, of
> course, we don't usually have access to the temperature profile.  Instead it
> provides a means of assessing possible errors arising from using the  tables
> "naively", and it leaves open the option of calculating different  versions of
> the tables when circumstances might require  them.

Three quick points:

1.  Should some effort be made by the publisher to update the Bowditch
"system" to reflect more current values of refraction etc.?

2.  As noted in previous discussions of T15 (formerly T9), there is an error
in the currently published equation behind the T15 tables.  The second term
is not under the square-root symbol. Tables are OK as computed, formula not
so.

3. While we pay it lip service, has anyone contacted the publisher/editor of
Bowditch's  American Practical Sailor to point out the errors compared to
the earlier versions (for example T15 equation)?

Bill

PS

Sadly IMHO, does in matter a whit when GPS is the blind King?  Carver 30's
with flying bridges and more canvas than a comparable sailcraft punching in
"go to waypoint" then slipping below--bridge unmanned--to flip up the 12V
blender and cavort before impacting the breakwater between the departure and
destination point?  Just another Darwin Award candidate? 

   

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