Apa itu tandem lift dan apa saja risiko khususnya?

Tandem Lift (Dual Crane Lift) adalah operasi menggunakan dua atau lebih crane untuk mengangkat single load yang terlalu berat atau besar untuk satu crane.

Kapan Tandem Lift Diperlukan:

• Load melebihi kapasitas single crane available
• Load sangat panjang (steel beam, bridge girder) yang perlu balance
• Constrained rigging point - tidak bisa lift dari center

Unique Hazards:

1. Load Sharing Uncertainty

• Difficult predict exact load distribution antara cranes
• If uneven - satu crane bisa overloaded
• Dynamic shift selama lift bisa change distribution

2. Synchronization

• Both crane must move exactly same rate
• Mismatch speed = load swing atau sudden shift

3. Communication Complexity

• Koordinasi antara 2 operators + signalman
• Miscommunication = catastrophic failure

4. Structural Load

• Side loading pada boom jika cranes not synchronized
• Can damage crane structure

Mandatory Requirements:

1. Detailed Engineered Lift Plan

• Must be prepared by qualified engineer
• Calculate load distribution per crane
• Derating applied: typically each crane rated at 75% capacity max
• Include rigging design, crane positioning, lift path

2. Designated Lift Director

• Experienced lift supervisor in overall charge
• Coordinates both operators
• Has authority untuk stop lift any time

3. Communication System

• Radio communication mandatory
• Dedicated channel, clear protocol
• All participants (2 operators, lift director, riggers) pada same channel

4. Pre-Lift Trial

• Test lift to verify load sharing
• Use load monitoring system (load cell) if available
• Adjust rigging if distribution tidak sesuai calculation

5. Qualified Personnel

• Both operators must have SIO dan experience di tandem lift
• Signalman specifically trained untuk dual crane operation

Operational Protocol:

1. Pre-lift meeting - all personnel briefed
2. Rig load per approved plan
3. Test lift - verify load sharing
4. Proceed dengan lift - slow, synchronized movement
5. Lift director give commands, operators execute simultaneously
6. Continuous monitoring selama lift

Emergency Procedure:

• If any issue - "STOP" call dari anyone
• Both crane hold position
• Assess situation sebelum proceed or abort

Tandem lift is ultra-high risk - only with proper engineering dan extreme caution!