23/09/2026
๐ฅ A jack-up rig doesnโt simply โgo up and down.โ The jacking system is carrying the entire story of how that rig moves, stands, and survives its operating condition.
๐ Technical Session | Baker Marine D88 Jacking System
๐ 375 ft Self-Elevating Offshore Rig
When we talk about the Baker Marine D88, the first thing I always like to make clear is the leg arrangement.
Because if you don't know how the legs are defined, the rest of the jacking system will quickly become confusing.
And on a three-legged offshore rig, the arrangement is actually very straightforward once you look at it correctly.
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๐ต 1. Start With the Three Legs
๐น The Baker Marine D88 is a self-elevating rig fitted with three triangular legs.
๐น The forward or bow leg is Leg A.
๐น When you are standing facing the bow leg:
๐ธ The leg on your left is the Starboard Leg โ Leg B.
๐ธ The leg on your right is the Port Leg โ Leg C.
This simple orientation matters.
When engineers discuss jacking operations, preload, leg position, inspection findings, or equipment problems, everyone needs to be talking about the same leg and the same reference point.
A small mistake in orientation can create a very big misunderstanding offshore.
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๐ต 2. What Makes the Jacking System Different?
The self-elevating rig is designed so the hull can move vertically along the three legs.
๐น Each leg has a triangular configuration.
๐น Welded along each leg are three rack sections.
๐น These racks mesh with pinions installed within the jacking assemblies.
๐น The jacking assemblies are housed inside the rig's jack houses.
This rack-and-pinion arrangement is what converts motor rotation into controlled vertical movement of the rig.
So when we say the rig can move up or down, we are not talking about a simple lifting operation.
We are talking about a coordinated mechanical system involving motors, gear trains, pinions, racks, jacking assemblies, electrical power and structural load.
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๐ต 3. How Many Jacking Assemblies Are We Talking About?
This is where the numbers become important.
๐น Each leg has three jacking assemblies.
๐น With three legs:
3 assemblies ร 3 legs = 9 jacking assemblies
The presentation material shows that each jacking assembly incorporates eight pinions, working against the rack arrangement on the leg.
The pinions engage the racks and transfer the mechanical forces required to move or hold the hull.
๐น The pinions operate through their associated gear trains and electric drive system.
This is why you should never look at a jacking system as โjust a motor.โ
The motor is only one part of a much larger mechanical power path.
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๐ต 4. The 36-Motor Picture
From the operating configuration discussed in the session, each jacking assembly is driven by four motors.
That gives us:
๐น 4 motors ร 3 assemblies per leg = 12 motors per leg
๐น 12 motors ร 3 legs = 36 jacking motors
So the complete rig can have a substantial distributed jacking drive system working across all three legs.
And this is exactly where system understanding becomes more important than memorizing numbers.
If one motor, gearbox, pinion or associated control element behaves differently from the others, the effect is not isolated to a single component.
The entire load-sharing behavior of the jacking system can become relevant.
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๐ต 5. What Can the Jacking System Actually Do?
The system provides controlled movement of the hull along the legs during floating and elevating conditions.
๐ธ Lifting and lowering the legs
๐ธ Lifting and lowering the platform
๐ธ Supporting the elevated hull under normal operating load
๐ธ Supporting the rig during preload conditions
๐ธ Holding the elevated weight while the jacking system is subjected to significant mechanical loading
During maximum preload arrangements, the jacking system is not simply moving the rig.
It is also participating in a condition where motors, gearboxes, pinions, racks and structural components are all dealing with substantial forces.
That is why understanding the load path is so important.
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๐ต 6. And Then There Is the Electrical Side
Another detail that deserves attention is the motor supply.
๐น The jacking motors discussed for this Baker Marine configuration are powered at approximately 690 V.
๐น The 690 V supply is applied directly to the jacking motor system rather than using the same 480 V arrangement discussed in some other systems.
That distinction matters during troubleshooting and maintenance.
You cannot assume that two jack-up rigs will have the same electrical architecture simply because both use rack-and-pinion jacking.
Always verify the actual system configuration, voltage level, motor arrangement, control architecture and power distribution of the rig in front of you.
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๐ก The real lesson from the Baker Marine D88 is this:
A jacking system is not one piece of equipment.
It is a complete mechanical and electrical chain.
Motor โ Gear Train โ Pinion โ Rack โ Leg โ Hull.
Every part has a job.
And when the rig is lifting, lowering, holding elevated weight or going through preload, every part of that chain becomes part of the operation.
๐ฏ If you understand the leg arrangement, the jacking assembly configuration, the rack-and-pinion mechanism, the motor distribution and the electrical supply, you stop looking at the jacking system as a collection of components โ and start seeing how the entire system actually works.
