A method and system for attaching a TLP to its tendons using pull-down
lines to rapidly submerge the hull to installation draft while
compensating for inherent hull instability during submergence and to
provide motion arrest and aid in station keeping. The system includes
tensioning devices mounted on the TLP, usually one for each tendon. Each
tensioning device is equipped with a pull-down line which is connected to
the corresponding tendon. The TLP hull is submerged to lock-off draft by
applying tensions to the pull-down lines connected to the top of the
tensions, or by a combination of applying tensions to the pull-down lines
and ballasting the hull. As the tensioners take in pull-down line, the
hull submerges, i.e. the draft increases. After lock-off, high levels of
tension in the pull-down lines can be rapidly transferred to the
connection sleeves by slacking the pull-down lines, thus allowing the TLP
to be made storm-safe much faster than by prior art methods which require
de-ballasting to tension the tendons. In concert with TLP installation,
the method may be used attach the mooring tendons to the seabed by
suspending and lowering the tendons into their foundation receptacle in
the seabed.