Oil States MCS Temporary Pile Grippers (TPGs) provide a means for temporarily securing a template or jacket to its driven piles while permanent structural connections are made. TPGs are mounted at the top of a template's pile sleeves or a jacket's skirt-pile sleeves during fabrication. After foundation piles are driven, one or more TPGs are actuated to grip the pile, securing the structure while the leveling operation continues and the permanent connections are made. No diver intervention is required. The high-strength, temporary connections provide the following important advantages during the installation process.

Faster Structure Leveling
TPGs facilitate the leveling process, because selected corners of the structure can be secured as leveling progresses, eliminating the need for multiple Latch-Lok™ tools. Improved grouting results. When grouting is used, the TPGs prevent relative movement while the grout cures, preventing grout shear-bond reduction.

Storm Security
The devices can be used to secure a jacket temporarily if weather forces the derrick barge off-location; total time required to secure a jacket is approximately 10 minutes. Accumulators maintain the Grippers in the closed position until installation operations resume, reducing jacket installation time. TPGs can shorten the critical path for jacket installation because many activities, such as hanging boat landings, can be performed while permanent connections are made.

Types of Temporary Pile Grippers
There are four basic types of Temporary Pile Grippers:

60-inch Type ST Gripper. Compact hydraulic or pneumatic rams provide a powerful radial gripping force that locks a template or jacket securely to piles.

60-inch Type ST Gripper welded into the skirt-pile sleeve of a 250-ft jacket.

72-inch Type ST Gripper on a 420-ft jacket.

Type ST (Standard) Grippers use compact, radially mounted hydraulic or pneumatic rams to drive serrated segments inward to grip the pile with a bi-directional grip. The hardened steel segments will grip over grout shear keys on the pile. Type ST Grippers can be furnished for any pile size and with bi-directional holding capacities up to 2000 tons, and they will work at any water depth. The Grippers can be actuated and released any number of times, with the double-acting rams ensuring positive release. For maximum economy, Type ST Grippers can be made retrievable. Also, these Grippers have integral stabbing cones, so retrieving them leaves a minimum of equipment on the installed template or jacket. Type ST Grippers require only a single, retrievable power unit.

Type CS (Collet Style) Grippers are pneumatically-actuated devices that have an inflatable elastomer bladder behind serrated collet fingers. When inflated, the bladder drives the fingers into the pile. Like Type ST Grippers, these are bi-directional and can be actuated and released repeatedly during the leveling operation. They have the highest load capacity, up to 5000 tons.

Type PS (Packer Style) Grippers are economical, pneumatically-actuated Grippers that use an elastomer packer element to effect a friction grip on the pile. Type PS Grippers have limited load capacity (100 tons or less) and are typically used only for minimal-concept structures.

Type SA (Spring Actuated) Grippers are economical, spring-actuated, "one-way" Grippers designed for use on temporary drilling templates. Type SA Grippers require no external power source for actuation or to maintain their grip for extended periods. However, once the slip-and-bowl mechanism is engaged, it cannot be released to lower a corner. The Grippers allow the template or jacket to slide up the pile for leveling, but when lifting force is relaxed, they grip the pile with weight-energized force. With Type SA Grippers, premature actuation is prevented by a retaining cable that holds the segments in the retracted position during pile-installation operations. When leveling operations begin, an ROV is used to cut the retaining cable to actuate the gripping segments. Type SA Grippers have load capacities up to 1000 tons.