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as an afloat move lasting more than 12-hours which does not
satisfy the requirements of an Extended Field Tow. In this
condition, the Jack Up Unit is afloat on its own hull with its legs
raised as with a Field Tow, but, for many Units, additional
precautions must be made. This is because the motion criteria for a
Wet Ocean Tow are more stringent than for a Field Tow. The
additional preparations may include installing additional leg
supports, shortening the leg by cutting or lowering, and securing
more equipment and cargo in and on the hull. A Dry Ocean Tow is
defined as the transportation of a Jack Up Unit on the deck of
another vessel. In this condition, the Jack Up Unit is not afloat, but
is secured as deck cargo. The motion criteria for the Unit is
dictated by the motions of the transportation vessel with the Unit
on board. Therefore, the precautions to be taken with regard to
support of the legs must be investigated on a case-by-case basis.
Generally, though, the legs are to be retracted as far as possible
into the hull so the Jack Up hull can be kept as low as practicable
to the deck of the transport vessel and to reduce the amount of
cribbing support. The other critical precaution unique to Dry
Ocean Tow is the support of the Jack Up hull. The hull must be
supported by cribbing on strong points (bulkheads) within the hull
and in many cases, portions of the hull overhang the side of the
transportation vessel. These overhanging sections may be exposed
to wave impact, putting additional stress on the hull, and if the
overhanging sections include the legs, the resultant bending
moment applied to the hull (and amplified by vessel motions) can
be significant. Calculations should be made to ensure that the hull
will not lift off the cribbing with the expected tow motions.
ARRIVING ON LOCATION
Upon completion of the Transit Mode, the Jack Up Unit is
said to be in the Arriving On Location Mode. In this Mode, the
Unit is secured from Transit Mode and begins preparations to Jack
Up to the Elevated Mode. Preparations include removing any
wedges in the leg guides, energizing the jacking system, and
removing any leg securing mechanisms installed for the Transit
thereby transferring the weight of the legs to the pinions.
SOFT PINNING THE LEGS
If an independent leg Jack Up Unit is going to be operated
next to a Fixed Structure, or in a difficult area with bottom
restrictions, the Jack Up Unit will often be temporarily positioned
just away from its final working location. This is called “Soft

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