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Oliv asked-

|I am facing a translation question about an ancient navigation
| instrument, it looks like on this picture:
| http://www.compensation-compas.com/renard.jpg
|
| In French, it's called "renard", that means "fox" in English.
| As you can see on the picture, it represents the compass' rose, and
in
| each direction, the branches of the rose are drilled by small holes,
| where wooden pins can fit.
| There is also (not really visible on the picture) another area where
| pins can fit, to represent the speed of the boat.
|
| It was used as follow. The driver had an hourglass beside him, and
| everytime it was empty, it was to be turned upside down, a pin was
added
| in the direction that had been followed during the previous watch,
and
| another one to describe the speed the boat had during that watch.
| Than, after some time, the navigator came by the "renard", and could
| have a good idea of the dead reckoning, reading it like that:
|
| From 00:00 to 04:00, traveled at 6 knots in the NNW.
| From 04:00 to 08:00, traveled a 6.5 knots in the NW,
| etc
|
|
| Would anyone know how this instrumnet is called in English?
============

It's a traverse-board. It allowed a record to be kept by a watchkeeper
who might be quite illiterate.

But its usage was rather different to the way Oliv explains it.

During a four-hour watch, the course would usually
be pegged every half-hour, at the turning of a half-hour glass, in one
of the 8 rings of 32 holes corresponding to compass-points, starting
from the inner ring. That course area looked very much like a
dartboard, and is clearly shown on Oliv's illustration..

At (usually) hourly intervals, the log was
streamed over the stern, and the resulting speed was pegged in the
columns for knots (integral knots and often fractional knots),
starting from the top. There were usually four such rows, then, but
practice varied considerably, between the various nations, trades,
vessels, and eras. That speed section of the board was usually
conspicuously placed as a rectangular block, usually mounted below the
course section. Oliv says that the speed section is "not really
visible on the picture", and I can't make it out at all. Is it
present, indeed?

The pegs were often made of bone, and attached by strings so they
didn't go astray.

At the end of the watch, the results, corrected for compass error,
would then be integrated up by the navigator, using a traverse table,
or some similar form of ready-reckoner, into Westings and Northings.
These were then summed up over the day's watches, to provide the DR
(dead-reckoning) travel from one noon to the next.

Within the French culture, there's a book by Jean Randier, which I
have in English translation (1980), as "Marine Navigation
Instruments". The French version dates from 1977, but I don't know its
exact title. It has photos of several such traverse-boards, some
elaborately decorated.

George.

contact George Huxtable at george@huxtable.u-net.com
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.

   

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