5 yearly special periodic survey

Alatas Service: Field Service, 5 yearly Special Periodic Survey
Location: Singapore
Manufacturer: NOV (National Oilwell Varco), BMC (Baker Marine Cranes)
Model: GL 4528-2S

Our client engaged Alatas Singapore to carry out a 5 Yearly Special Periodic Survey on 3 BMC Offshore cranes (Baker Marine Cranes), which was carried out by Alatas’ Afloat Repair team, led by Senior Offshore Crane Engineers.

In addition to the scope of work, Alatas Specialised Workshop was entrusted with the overhaul of mostly NOV equipment (National Oilwell Varco).

These components were offloaded from the rig at dry-dock to our workshop for thorough inspection, overhaul and testing. Upon completion of repairs, the offshore equipment was sent back on board and installed, function tested and recommissioned by our NOV specialist engineers.

List of components for 5 Yearly Special Periodic Survey

  • JD Neuhaus 50ton Monorail Air Hoist (x4 units)
  • NOV Utility Winches (x2 units)
  • NOV Racking Winches (x2 units)
  • NOV Man Riding Winches (x2 units)
  • NOV Grip Head (x1 unit)
  • NOV Singles Pick-Up Elevator system (x1 unit)
  • NOV Rotary Table (x1 unit)
  • 12ton BMC Crane Ball Hooks (x3 units)
  • 30ton BMC 900 & BMC 1600 Crane Aux. Hook Block (x1 unit)
  • 55ton BMC 2250 Crane Main Hook Block (x2 units)

1. JD Neuhaus 50 ton Monorail Air Hoist (x4 units)

  1. The monorail air hoist consisted of components such as motors, gearboxes, 80m of chains, chain buckets, rollers and hangers for hoses
  2. All units were dismantled from the main structure, cleaned to proper and inspected thoroughly
  3. All gears and pins were NDT tested and no defects found
  4. All parts such as bearings, seals, screws, fittings, filters were replaced
  5. The complete dismantled structure was sandblasted and painted with three layers of marine grade paint
  6. For the 80M chain, all existing grease were removed, sandblasted, NDT tested & re-lubricated with a special non-drip sticky chain grease to protect the environment
  7. Upon completion of overhaul on all individual components, the complete structure was re-assembled and pressure tested accordingly in Alatas Singapore Workshop.

Results were found satisfactory and delivered unit onboard the rig.


2. NOV Utility Winch, Racking Winch, Tugger Winch overhaul

The Utility & Racking winch consists of components such as motor, gearbox and drum and the winch body. All units were dismantled from the main structure, cleaned to proper and inspected thoroughly.

All gears and pins were NDT tested and no defects found. All parts such as bearings, seals, screws, filters, brake discs, pneumatic hoses & fittings and wire ropes were replaced.

The complete dismantled winch frame was sandblasted and painted with three layers of marine grade paint.

Upon completion of overhaul on all individual components of the utility winches, the complete structure was reassembled and pressure tested accordingly in the Alatas Workshop. Results were found satisfactory and the tugger winches were delivered back on board the rig.


3. NOV Man Riding Winch Overhaul

The National Oilwell Varco man riding winch consists of components such as winch motor, hook stop, drum, pressure roller, hydraulic and mechanical brake calipers with brake discs, wire guide, emergency stop valve and controls.

All components were dismantled, cleaned to proper and inspected thoroughly. All gears and pins were NDT tested and no defects found. All parts such as bearings, seals, screws, fittings, filters, hoses & fittings were replaced to new. The complete dismantled structure was sandblasted and painted with 3 layers of marine grade paint.

Upon completion of overhaul, the complete structure was re-assembled and the man riding winches were dynamically load tested the unit for 150KG SWL test manually and with remote control, as per NOV winch test procedure.

Followed by 225 kg dynamic brake test and 300 kg static brake test, holding for 10 minutes in Alatas Workshop. Results were found satisfactory and a test certificate was issued and man riding winch was supplied back on board the rig.

4.NOV Grip Head HydraRacker x-y

The NOV AS Grip head 3 1/2″ – 9 3/4″, drawing #D1197-A0004 consists of components such as cylinders, actuators, valves and controls.

All units were dismantled from the main structure, cleaned to proper and inspected thoroughly. Parts such as seals and fittings were replaced with new parts.

Upon completion of overhaul on all individual components, the complete structure was re-assembled and pressure tested the unit up to 315 Bar in Alatas Workshop. Results were found satisfactory and delivered unit on-board rig.


5. VARCO Bj Singles Pick-Up Elevator system

The NOV Singles Pick-Up Elevator system, (Varco BX 4-50, 4-50, 4-75 & 5 hydraulic operated elevator) consists of components such as six cylinders, five valve blocks and controls.

  • All units were dismantled from the main structure, cleaned to proper and inspected thoroughly
  • All necessary parts were NDT tested and no defects found
  • All parts such as bearings, seals, split bushes for cylinders, screws, fittings, hoses & fittings, wire ropes with thimble were replaced
  • One of the cylinder pistons was seized and had to be newly fabricated on top urgent basis
  • The completely dismantled structure was sandblasted and painted with three layers of marine grade paint

Upon completion of overhaul on all individual components, the complete structure was reassembled. Function and pressure tested the unit at 210 Bar in Alatas Workshop. Results were found satisfactory and delivered unit on-board the rig.

6. NOV Independent Rotary Drive D-495

The National Oilwell Varco D-495 (PetroJack Rotary Drive, NOV Drawing PL X132-3457) was overhauled by Alatas Engineering Workshop.

This offshore rotary table was completely dismantled into its components and the following items were fully overhauled, dynamically tested and issued with test protocol and repair certificate before delivery:

  • Hagglunds Compact Motor CA70
  • Hagglunds Compact Lamella Brake BICA 24
  • Hyd. Controls Valve Package, NOV drawing PL 1313657
  • Moog Valves, Series D661K, D662K, D663K, D664K and D665K
  • NOV Pressure Accumulators

7. Hook Blocks (12ton, 30Ton & 55Ton)

The hook blocks, 12ton (x3 units), 30ton (x1 unit) & 55ton (x2 units) were offloaded to our workshop for a complete inspection, overhaul them adhering to DROPS compliant and load testing them, witnessed by ABS Surveyor.

All hook blocks were completely dismantled cleaned to proper and NDT inspected before repair works. No defects were found through the NDT test. Hence, all necessary parts such as bolts (xylan quoted), bearings, seals were replaced.

The dismantled structure was sandblasted and painted with three layers of marine grade paint. During reassembly, all Tie Rods were fitted with Nylon Lock Nuts and all other bolts secured with locking wire.

SWL was stencilled and hard stamped into the block body along with the testing information and unique ID number. Upon reassembly of the complete hook blocks, they were load tested according to previous certificates issued by owner as follows in the presence of ABS surveyor:

  • SWL 12ton Hook block = 24ton Proof Load
  • SWL 30ton Hook block = 55ton Proof Load
  • SWL 55ton Hook block = 83.18ton Proof Load

To conclude the 5 Yearly Special Periodic Survey, upon load test, we immediately engage NDT test to be carried out on the Hook area to check for defects and when no defects were found, all hooks were delivered on-board rig.

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