Attention should be given to the skirt that has to be applied
around the connection, which means a small opening
should be made in the skirt for the connection cable.
Again the bolted connection could be replaced by a welded
connection as long as a pretension on the connection
can be guaranteed so the connection won’t slide along
the cable at bottom of the skirt.
3.6.5 Buoyancy Elements
To keep the boom floating, buoyancy elements will be applied.
First a variant was investigated with steel pipes,
but this variant was found not suitable due to the wave
movements at the surface more easily overtopping
(waves going over the boom). Therefore a flexible boom
concept was preferred over a stiff one. For the buoyancy
elements there are multiple options.
Off-the-shelf buoyancy elements are preferred. Simple
buoyancy elements can be applied. These elements are
designed to last in marine environments and are capable
of taking wave and wind impact. Other use of these elements
is as fender for ships, preventing the ships from
bumping against quay walls.
Another option is to apply dredging pipes that are very
flexible and suitable for marine environments. This option,
however, will be rather expensive compared to the
buoyancy elements. Three options are outlined below.
Option 1
The first option is to use foam-filled or pneumatic fenders.
These fenders will be placed every four meters. The
skirt is placed around the fenders. The advantages and
disadvantages of the fenders are briefly described below.