# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: DR thread from Nov-Dec '04
From: Doug Royer
Date: 2005 Jan 18, 10:36 -0800

```After reading my origonal post on this subject I noticed I wrote the set
discription incorrectly.I appologise for any confusion I caused and will
clear it up now.
If the wind is out of the north at 360 * T the set will be in the direction
of 180 * T.If the wind is on the starboard beam the resulting current will
push the vessel toward the south.That issue now being corrected the set of
the wind driven current will be in the direction of 220 * T,not 320 * T.
Again, 360 *T - 180 * T = 180 * T. 180* T + 40 *(to the right of the wind
direction)= 220 * T.
Don't let my mistake deminish the importance of this effect.

Doug

> When engaged in commerce shipping time is money and
> money is time.

I also imagine it takes more than pocket change in fuel for those few extra
miles as well. Must make a cigarette boat look like a hybrid economy car ;-)
Do you have a ball-park figure for gallons per mile for an average loaded
freighter?

The larger,older freighters use bunker oil for propusion.Some of the newer
vessels use gas turbine technology but the majority use diesel.The
nomenclature for fuel cunsumption in these vessels is in barrels/hour for a
given rpm of the shaft.I believe there are 42 gallons/barrel.A vessel of
this size can easily consume 100s of barrels/day depending on speed,draft
and sea conditions.I'll get an example of this tonight and post it tomorrow.

> "The Merchant Marine Officer's Handbook" 4th or 5th edition devotes space
to
> it in the chapters dealing with shiphandling and pilotting. I haven't seen
a
> 6th edition yet.
>
> Other than that one book perhaps in other marine teaching institution's
> sylabus as that is where I was 1st exposed to it.

I first noticed it in the Annapolis Book of Seamanship, and then aware of
it, noticed it in a a couple of other texts.  Memory fails, but I would
guess Dutton's, Chapman, and Bowditch would be rounded up as the usual
suspects for a line up.

I'll look at my older editions of Dutton's and Bowditch tonight and see if I
can find referance to this in them.I don't remember it being in Dutton's but
it's been awhile since I dusted my copy off.
What is the "Annapolis Book of Seamanship" ? Is it a book used to teach

Bill

```
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