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Pinning” the legs or “Standing Off” location. This procedure
involves lowering one or more legs until the bottom of the spud
can(s) just touches the soil. The purpose of this is to provide a
“Stop” point in the Arriving On Location process. Here, all
preparations can be checked and made for the final approach to the
working location. This includes coordinating with the assisting
tugs, running anchor lines to be able to “winch in” to final
location, powering up of positioning thrusters on the Unit (if
fitted), checking the weather forecast for the period of preloading
and jacking up, etc.
FINAL GOING ON LOCATION
Whether a Unit stops at a Soft Pin location, or proceeds
directly to the final jacking up location, they will have some means
of positioning the Unit so that ballasting or preloading operations
prior to jacking up can commence. For an independent leg Jack Up
Unit, holding position is accomplished by going on location with
all three legs lowered so the bottom of the spud can is just above
the seabed. When the Unit is positioned at its final location, the
legs are lowered until they can hold the rig on location without the
assistance of tugs. Mat type Jack Up Units are either held on
location by tugs, or they drop spud piles into the soil. These spud
piles, usually cylindrical piles with concrete fill, hold the Unit on
location until the mat can be ballasted and lowered.
JACKING
A mat Unit will jack the mat to the seabed in accordance
with the ballasting procedure. Once the mat has been lowered to
the seabed, the hull will be jacked out of the water. The Unit then
proceeds to Preload Operations . All Independent leg Units must
perform Preload Operations before they can jack to the design air
gap. Most independent leg Units do not have the capacity to
elevate the Unit while the preload weight is on board. For these
Units, the next step is to jack the hull out of the water to a small air
gap that just clears the wave crest height. This air gap should be no
more than five (5) feet. Once they reach this position, the Unit may
proceed with Preload Operations.
PRELOAD OPERATIONS
All Jack Up Units must load the soil that supports them to
the full load expected to be exerted on the soil during the most
severe condition, usually Storm Survival Mode. This preloading
reduces the likelihood of a foundation shift or failure during a
Storm. The possibility does exist that a soil failure or leg shift may

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