An offshore lifting construction is able to control buoyancy for the lifting
of
jackets for offshore platforms. The lifting construction is designed such that
it can be ballasted for raising and lowering and such that it can take several
positions. The lifting construction is designed as an arm equipped with a joint
for attachment to a vessel. The arm includes two substantially parallel longitudinal
elements with intermediate supporting elements. One of the ends of the arm includes
at least two tubular branches substantially perpendicular to the longitudinal direction
of the substantially parallel longitudinal elements. At least one of the elements
of the arm includes at least one ballastable tank. The arm is equipped with device
for attachment to the jacket that is to be lifted. A method for rising jackets
or jacket legs for offshore platforms is also described.
