Scientific Reports
Scientific Reports
>Received: by revelle.UCSD.EDU (SMI-8.6/UCSDUUCPGENERIC.4)
id RAA13305 to ; Thu, 19 Nov 1998 17:13:28 GMT
Date: Thu, 19 Nov 1998 17:13:28 GMT
From: revelle!cpm@sdsioa.ucsd.edu (Chris DeMoustier)
To: shipsked@ucsd.edu, capt@mpl.ucsd.edu
Subject: Weekly Scientific Report - R/V Revelle
Cc: cpm@mpl.ucsd.edu, wild@spawar.navy.mil
Weekly scientific report from R/V Revelle (11-18 Nov 98)
A team of scientists and technicians from MPL, SPAWAR, MEC Analytical Systems,
and A.D. Little left MARFAC on November 11, 1998 aboard R/V Revelle to
collect sediment samples around the ex USNS Agerholm which lies in 800 m
of water depth on the western slope of Tanner Basin, 130 nm from
shore. The sediment samples will be analyzed to assess the
environmental impact of the wreck.
On our way to station, we stopped SW of San Clemente Island to test a new
coring device equipped with three coring cylinders 18" in diameter.
This tri-corer retrieved three good samples of sandy silt in 800 m of
water depth.
Once on station, we deployed 4 acoustic transponders and ran a sidescan
survey of the wreck site with the Deep Tow Fish6 instrument package.
Passes within 100 m, then 50 m from the wreck have provided very nice
sidescan images of the wreck. We have conducted a video reconnaissance
of the wreck, visually identifying the bow, the bridge and the stern
section, as well as refining our position estimates for these points.
Coring operations have remained unsuccessful after 15 attempts because
we have not managed to get enough penetration into a sediment
containing 80% coarse material. A gravity core 2" in diameter and 1 m
long retrieved 9" of sediment showing evidence of a hard packed layer
4" to 5" below the water sediment interface.
For the first five days, operations have benefited from extremely
clement weather and from the ship's excellent station keeping
capabilities. Jim Charters resurrected ship-to-shore email communications
on Nov 15th, triggering a run on computer terminals aboard ship.
Christian de Moustier
This cruise is being funded by a grant from NRaD.
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