Omni Tanker Pty Ltd

Commercial-in-confidence

25th August 2023

United States Road Tanker
Chassis Doubler Plate Inspection
and Weldment Procedure

OTM 230024.01 – USRT Chassis Double Plate Weldment Procedure

Page 1

Omni Tanker Pty Ltd

25th August 2023

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1 Scope
This document details the procedure for a subcontractor to complete the weldment of flange
doubler plates on an Omni Tanker United States Road Tanker Cargo Tank Motor Vehicle
(CTMV).

2 Bill of materials
The table below lists the possible materials which may be required to conduct the work(s) as
described in this procedure.
Item #
Doubler
Type
1
2
3

Length

Width

Thickness

Qty

Material

76” (1930mm)
76” (1930mm)
49.2” (1250mm)

4” (102mm)
4” (102mm)
4” (102mm)

1/4” (6.35mm)
1/4” (6.35mm)
3/16” (4.77mm)
OR
1/4” (6.35mm)

2
2
2

Flat bar; 304L SS
Flat bar; 304L SS
Flat bar; 304L SS

OTM 230024.01 – USRT Chassis Double Plate Weldment Procedure

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Omni Tanker Pty Ltd

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25th August 2023

3 Procedure
3.1 Chassis inspection
There are three distinct pairs of doubler plates required on both sides of the CTMV chassis.
The CTMV may not yet have all flange double plates welded to the chassis. The figure below
shows the approximate location and type of each on the chassis in red (Type 1), blue (Type
2), and green (Type 3).

Figure 1: Typical location and Types of Doubler plates on CTMV Chassis
Doubler plate Type 1 is 304 SS and located towards the front of the chassis. It measures 76”
(or 1930mm) long, 4” (100mm) wide, and of ¼” (6.35mm) thick. It is typically welded to the
lower surface of the top flange on the chassis Z-section (driver and curb sides of the chassis).
Each doubler plate starts approximately 28” (710mm) from the front of the trailer. These are
represented in red within Figure 1.
Doubler plate Type 2 is 304 SS and also located towards the front of the chassis. It measures
76” (or 1930mm) long, 4” (100mm) wide, and of ¼” (6.35 mm) thick, 304L Stainless steel. It is
typically welded to the upper surface of the bottom flange on the chassis Z-section (driver
and curb sides of the chassis). Each doubler plate starts 1” (25mm) away from the first trailer
cross member. These are represented in blue within Figure 1.
Doubler plate Type 3 is 304 SS and located about a quarter to a third of the way down the
chassis. It measures 49.2” long (1250mm), and 4” wide (100mm), and of 9 gauge (4 mm) thick.
It is typically welded to the upper surface of the upper flange the chassis Z-sections (driver
and curb sides of the chassis), starting approximately 0.2” (5mm) from the second set of Zsections on the trailer. Shown as green in Figure 1.
Use the checklist at the end of this document to assist with noting these Doubler plates are
present.
If any of the Doubler plates listed above are not present on the CTMV chassis, refer to the
following sections for installation and weldment instructions.

OTM 230024.01 – USRT Chassis Double Plate Weldment Procedure

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Omni Tanker Pty Ltd

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25th August 2023

3.2 General installation procedures
If upon inspection it is found that if any of the doubler plates in Section 3.1 are not present,
the following overall steps should be followed:
1.
2.
3.
4.

Take photos of the affected region(s) and notify Omni Tanker;
Determine exactly which pair(s) of Doubler plates are required;
Before performing any works, drain the tank of any residual fluids or chemicals;
Place CTMV on stands. If Doubler plate Type 2 requires installation, place the stands
in a manner which will allow for the safe removal of the upper 5th wheel coupler;
5. Remove the upper 5th wheel coupler (if installing Doubler plate Type 2);
6. Cut the required materials as per Section 2, as required;
7. Disconnect or detach the cabling and pneumatics near the Doubler plate regions to be
welded, or move as far away as practicable, to avoid damage;
8. Perform the welding procedures as specified in Sections 3.3, 3.4, and/or 3.5 as
necessary;
9. Pickle or TIG brush welded the applicable regions where doubler plates have been
installed;
10. Re-attach cabling / pneumatics; and
11. Re-attach the upper 5th wheel coupler (if required).

OTM 230024.01 – USRT Chassis Double Plate Weldment Procedure

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Omni Tanker Pty Ltd

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25th August 2023

3.3 Doubler Plate Type 1 – Installation Instructions
This section details welding instructions for Type 1 Doubler plates, in the case they are not
present on the chassis:
1. Cut two lengths of 304L SS flat bar, each 76” (1930mm) long, 4” (102mm) wide and
0.25” (6.35mm) thick, as per as per Item 1 in the bill of materials listed in Section 2.
2. Figure 2 shows the location of the Doubler plate for the curb side of the chassis only,
located underneath the top flange of the Z-section.

Figure 2: Location of Type 1 Doubler plate
3. The Doubler plate in step 2 is to have the following fillet welds applied:
a. 3/16” (4mm) continuous fillet welds on each 4” (102mm) end;
b. 3/16” (4mm) stitch fillet welds, 4.5 inch on, 4.5 inch off.
4. Repeat steps 2 and 3 for the driver side of the cargo tank.
5. Figure 3 shows the completed installation.

Figure 3: Completed Type 1 Doubler plate installation

OTM 230024.01 – USRT Chassis Double Plate Weldment Procedure

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Omni Tanker Pty Ltd

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25th August 2023

3.4 Doubler Plate Type 2 – Installation Instructions
This section details welding instructions for Type 2 Doubler plates, in the case they are not
present on the chassis:
1. Cut two lengths of 304L SS flat bar, each 76” (1930mm) long, from 4” (102mm) wide
by 0.25” (6.35mm) thick, as per Item 2 in the bill of materials listed in Section 2.
2. Figure 4 shows the location of the Doubler plate for the curb side of the chassis only,
located underneath the bottom flange of the Z-section.

Figure 4: Location of Type 2 Doubler plate
3. Tack weld flat bar in position, and check that location will not interfere with fitment
of upper 5th wheel coupler;
4. The Doubler plate in step 2 is to have the following fillet welds applied:
a. 3/16” (4mm) continuous fillet welds on each 4” (102mm) end;
b. 3/16” (4mm) stitch fillet welds, 4.5 inch on, 4.5 inch off.
5. Repeat steps 2 to 4 for the driver side of the cargo tank.
6. Figure 5 shows the completed installation.

Figure 5: Completed Type 2 Doubler plate installation

OTM 230024.01 – USRT Chassis Double Plate Weldment Procedure

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Omni Tanker Pty Ltd

Commercial-in-confidence

25th August 2023

3.5 Doubler Plate Type 3 – Installation Instructions
This section details welding instructions for Type 3 Doubler plates, in the case they are not
present on the chassis:
1. Cut two lengths of 304 SS flat bar, each 49.2” (1250mm) long, from 4” (102mm) wide
by 3/16” (4.77mm) or ¼” (6.35mm) thick, as per Item 3 in the bill of materials listed in
Section 2.
2. Figure 6 shows the location of the Doubler plate for the curb side of the chassis only,
located underneath the bottom flange of the Z-section.

Figure 6: Location of Type 3 Doubler plate
3. The Doubler plate in step 2 is to have the following fillet welds applied:
a. 3/16” (4mm) continuous fillet welds on each 4” (102mm) end;
b. 3/16” (4mm) stitch fillet welds, 4.5 inch on, 4.5 inch off.
4. Repeat steps 2 and 3 for the driver side of the cargo tank.
5. Figure 7 shows the completed installation.

Figure 7: Completed Type 2 Doubler plate installation

OTM 230024.01 – USRT Chassis Double Plate Weldment Procedure

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3.6 Weld cleanup
All welds and weld zones are to have heat tint removed (pickled).

END OF PROCEDURE

OTM 230024.01 – USRT Chassis Double Plate Weldment Procedure

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Omni Tanker Pty Ltd

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25th August 2023

Doubler plate inspection checklist
Doubler plate Type
Type 1
Type 2
Type 3

Present?
[ ] YES
[ ] NO
[ ] YES
[ ] NO
[ ] YES
[ ] NO

Comment
If YES, install per Section 3.3
If NO, no action required
If YES, install per Section 3.4
If NO, no action required
If YES, install per Section 3.5
If NO, no action required

Doubler Plate installation checklist
Doubler plate Type
Type 1

Welded?

Welds cleaned?

Photographed?

Reference section
Section 3.3

Type 2

Section 3.4

Type 3

Section 3.5

Date of completion: ____________________
Name of person responsible for completion: _____________________________
Signature of person responsible for completion: __________________________

OTM 230024.01 – USRT Chassis Double Plate Weldment Procedure

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Omni Tanker Pty Ltd

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26th October 2023

United States Road Tanker –
Cradle Washer Plate Installation
Procedure

OTM 230029.02 – USRT Cradle Washer Plate Installation Procedure

Page 1

Omni Tanker Pty Ltd

26th October 2023

Commercial-in-confidence

1 Scope
This document details the installation procedure of washer plates onto the United States
Road Tanker (USRT) barrel support frame cradles.

2 Bill of Materials
There are two options for washer plate thicknesses depending on material availability:
Flat bar docking method (may require 1/32 edge chamfer for fitment):
Option
1

Length
8.07” (205 mm)

Width
3” (76.2 mm)

Thickness
1” (25.4 mm)

Qty
12

2

8.07” (205 mm)

3” (76.2 mm)

1/2" (12.7 mm)

24

Material
304SS, 316SS or
201LN
304SS, 316SS or
201LN

Profiled plate method:
Option
1

Length
8.07” (205 mm)

Width
75 mm

Thickness
1” (25.4 mm)

Qty
12

2

8.07” (205 mm)

75 mm

1/2" (12.7 mm)

24

Material
304SS, 316SS or
201LN
304SS, 316SS or
201LN

Figure 1: Dimensions of docked flat bar washer plate. Note 76.2 mm width changes to 75
mm width for profiled washer plate method

OTM 230029.02 – USRT Cradle Washer Plate Installation Procedure

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Omni Tanker Pty Ltd

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26th October 2023

3 Procedure
The procedure to install the washer plates is as follows:
1. Remove all strap covers.
2. Loosen the fasteners on strap 1 only on both the driver side and curb side of the barrel
support frame. Leave the fasteners on other straps tightened. Refer to Figure 2.

Figure 2: Driver side vs Curb side of Barrel Support Frame, Strap Numbering
3. Remove the nyloc nuts and washers located on the underside of the cradle harness
channel on Cradle 1. Refer to Figure 3 for nut location and cradle numbering.

OTM 230029.02 – USRT Cradle Washer Plate Installation Procedure

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Omni Tanker Pty Ltd

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26th October 2023

Figure 3: Diagram of cradle and strap
4. Test fit the 1” thick washer plate (Option 1) or one of the two 1/2" thick washer plates
(Option 2) ensuring the washer plate sits flush with the bottom face of the cradle
harness channel. If required, chamfer the edges of the washer plate. Refer to Figure 4
for washer plate location.
Note: This step is not required if a hex plate is installed on the underside of the cradle
harness channel.

Figure 4: Location of 1” thick washer plate relative to cradle harness channel
OTM 230029.02 – USRT Cradle Washer Plate Installation Procedure

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Omni Tanker Pty Ltd

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26th October 2023

5. Install washer plate(s) and check that the fasteners extend at least 1 inch below the
washer plate(s). If required, replace existing fasteners for longer A2-70 or equivalent
fasteners (304 SS fastener with proof load exceeding 100 ksi).
6. Reinstall washers and new nyloc nuts, applying anti-seize if required. Refer to Figure
5 and Figure 6.

Figure 5: Option 1 installed

Figure 6: Option 2 installed

OTM 230029.02 – USRT Cradle Washer Plate Installation Procedure

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Omni Tanker Pty Ltd

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26th October 2023

7. Tighten fasteners to 55 lb-ft (75 Nm).
8. Tighten fasteners to 70 lb-ft (95 Nm).
9. Note that Steps 2 to 7 are required to be undertaken on the same day to avoid rubber
spring back (opposite to compression set).
10. Repeat Steps 2 to 9 for the remaining Straps / Cradles in the following order: Strap /
Cradle 2, Strap / Cradle 3, Strap / Cradle 4, Strap / Cradle 5, and Strap / Cradle 6.
11. Reinstall strap covers.
12. Fill out the completion checklist attached at the end of this protocol

END OF PROTOCOL

OTM 230029.02 – USRT Cradle Washer Plate Installation Procedure

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Omni Tanker Pty Ltd

26th October 2023

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USRT Cradle Washer Plate Installation Completion Checklist
This USRT Cradle Washer Plate Installation Completion Checklist (OTM 230029, Page 7) is to
be filled out and returned to Omni Tanker.
Cargo Tank Serial Number:
Thickness of washer plates installed:
Quantity of washer plates installed:
Item
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14

Checklist Item

Complete
(Y/N)

Installation of washer plate – Cradle 1, driver side
Installation of washer plate – Cradle 1, curb side
Installation of washer plate – Cradle 2, driver side
Installation of washer plate – Cradle 2, curb side
Installation of washer plate – Cradle 3, driver side
Installation of washer plate – Cradle 3, curb side
Installation of washer plate – Cradle 4, driver side
Installation of washer plate – Cradle 4, curb side
Installation of washer plate – Cradle 5, driver side
Installation of washer plate – Cradle 5, curb side
Installation of washer plate – Cradle 6, driver side
Installation of washer plate – Cradle 6, curb side
All strap fasteners tightened to 70 lb-ft (95 Nm)
Strap covers installed

Date of completion:
Name of person responsible for job completion:
Signature of person responsible for job completion:

OTM 230029.02 – USRT Cradle Washer Plate Installation Procedure

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