Research, development, production and evaluation of innovative grab sampling devices with a view to improving the quality and efficiency of sea-bed sediment sampling
- Reference:
- 08/P18
- Start Date:
- 17 July 2008
- Amount Funded:
- £43,600 (for Phase I only)
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- Organisation:
- Gannet Scientific Services (with Plymouth Marine Laboratory and Cyclone Marine Ltd)
- End Date:
- 01 February 2009
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It is probable that a major factor in grab-sampling difficulties
lies in a design feature common to all current grab types. That is,
the closure of the grab jaws depends on the lifting tension of the
grab cable. This obviously limits the initial closing force on the
jaws to the weight of the grab, but also relies on a near vertical
angle of the cable for efficient sampling. Any significant sideways
pull will tend to pivot the grab and drastically affect sampling
efficiency.
There are a number of possible solutions in grab design that
might solve or alleviate this problem. Either the grab can be
designed so that a sideways pull by the cable is not as likely to
tilt or lift the grab as the jaws close, or alternatively, a
departure from conventional design can be made whereby the closure
of the jaws is independent of the cable. This project aims to
investigate both of these routes. Two prototypes were
developed:
The First Prototype: Minimising the effect of sideways pull on
the cable.
The Second Prototype: A Stored Energy Twin Sampling Device (the
Costerus Twin Grab).
Addendum Report
In July 2009, compatibility trials of the twin grab were
conducted as part of the East Coast REC survey work. A short
report on the findings of these trials is now available for
download (May 2010)
MEPF REC 08/04 - Addendum Report