DI-020_REV_2_WEIGHT_CONTROL_PLAN.pdf

Data Item DI-020

Contract 6913G623P800007 Weight Control Plan

Submitted by:

Loch Harbour Group 3060 Williams Drive, Suite 510

Fairfax, Virginia 22031

Preliminary/Contract Design of Motor Vessel Ranger IV

Contract No.: 6913G623P800007

CLIN-00100

DI-020 Weight Control Plan Revision 2

Submittal Date: August 13, 2024

DISTRIBUTION Statement C: Distribution authorized to the U.S. Government agencies and their Contractors.

Other request for this document shall be referred to US Department of Transportation Volpe Center.

This report, drawing, design, concept, and specification are the intellectual property of Loch Harbour Group, LLC, and/or TAI ENGINEERS, L.L.C and contains information which is proprietary. The rights defined below are reserved by Loch Harbour Group, LLC, and/or TAI Engineers, LLC. The United States Government's rights to use, modify, reproduce, release, perform, display, or disclose these technical data are unrestricted. Any reproduction of technical data or portions thereof marked with this legend must also reproduce the markings

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TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

ACRONYMS AND ABBREVIATIONS

REVISION TABLE

A. INTRODUCTION

B. APPROACH TO WEIGHT MANAGEMENT

B.1.Weight Control Organization

B.2. Phase I Weight Control Tasks

B.3. Phase II Weight Control Tasks

C. RANGER IV WEIGHT CONTROL PLAN

D. MONITORING WEIGHT GROWTH

E. MARGINS AND TRENDS

E.1. Adverse Trends in Weight Report

F. RISK MITIGATION

G. REFERENCES

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LIST OF TABLES

Table 1 Team LHG history of Weight and VCG control Table 2 Design Characterization Ratings SAWE RP 14 Table 3 Sample Contractor Design Weight Estimate Summary

LIST OF FIGURES

Figure 1 Team LHG’s Production Design (ShipConstructor) – Model Illustrating Level of Detail Figure 2 Weight Risk Assessment SAWE RP 14 Figure 3 KG Risk Assessment SAWE RP 14 Figure 4 Sample Weight Trend Plot ........................................................... Error! Bookmark not defined.

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ACRONYMS AND ABBREVIATIONS

ACRONYM DESCRIPTION

3D THREE DIMENSIONAL

ART ANTI-ROLL TANK

ASTM AMERICAN SOCIETY FOR TESTING AND MATERIALS

CDWE CONTRACTOR DESIGN WEIGHT ESTIMATE

CG CENTER OF GRAVITY

D&C DESIGN AND CONSTRUCTION

DD&C DETAILED DESIGN AND CONSTRUCTION

DR DESIGN REVIEW

EOSL END OF SERVICE LIFE

IAW IN ACCORDANCE WITH

LHG LOCH HARBOUR GROUP, INC

PM PROGRAM MANAGER

PO PURCHASE ORDER

NTE NOT TO EXCEED

SAWE SOCIETY OF ALLIED WEIGHT ENGINEERS

TAI TAI ENGINEERS, LLC

VCG VERTICAL CENTER OF GRAVITY

WCC WEIGHT CONTROL COORDINATOR

WCP WEIGHT CONTROL PLAN

WCT WEIGHT CONTROL TEAM

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REVISION TABLE

REVISION DESCRIPTION DATE AUTHOR

0 Initial submission 05-18-2024 TAI 1 Updated to address Government comments 07-26-2024 TAI

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A. INTRODUCTION

The primary objective of Team LHG’s approach to weight, Centre of Gravity (CG), and moment management was to ensure that the NPS RANGER IV complied with all contract weight, CG trim, and list requirements at the time of delivery. This was accomplished through a rigorous plan to monitor and control the weight growth and margin consumption during the Preliminary, Contract, and Detail Design and Construction. The weight control plan was fully consistent with the Society of Allied Weight Engineers (SAWE) Recommended Practices for Marine Vehicles Recommended Practice No. 12, Issue D. It must be noted that Team LHG’s RANGER IV included a total design and construction (D&C) margin of 12% to mitigate the risk involved in producing this vessel; this included contract specified margins. Team LHG’s RANGER IV was pre-designed so that any unused margin converts to additional payload, such as endurance or End of Service Life (EOSL) allowance, without compromise to its stability or seakeeping.

B. APPROACH TO WEIGHT MANAGEMENT

Team LHG’s Weight Control Plan (WCP) defined the responsibilities and standard procedures that will be used to determine and track the weight of the vessel. The purpose of the WCP was to ensure that the delivered vessel is fully compliant with all weight and center of gravity criteria listed in the Ranger IV Specification.

B.1.Weight Control Organization

The WCP was executed from contract award to ship delivery and was controlled and administered by the Weight Control Coordinator (WCC) who reports directly to the Program Manager (PM). The PM provided periodic weight updates to Team LHG’s senior management. The WCP required close cooperation between the engineering team, shipyard, equipment suppliers, and Weight Control Team (WCT), with regular oversite from senior management. The WCT core personnel of designers and engineers were under the supervision of the WCC. The WCT maintained complete and accurate weight records and shall prepare weight reports for review and approval by the Program Management Team.

Team LHG was responsible for executing the weight control measures developed by the WCT in the preparation of the contract design drawings. Care was taken to monitor all weight input to prevent any undue weight growth. Timely reporting of weight data, detection of adverse trends, and development of recommended corrective actions were essential for the effective implementation of the WCP.

B.2. Phase I Weight Control Tasks

The data available for the RANGER IV baseline designs was incorporated, where appropriate, in early design cycles. These were updated/replaced with RANGER IV details as the design developed. The weight impact of noise control features were estimated in the initial weight calculations, and the estimates were refined as necessary according to requirements (single or double isolation mounted gensets, piping flexibility and mounting systems, and noise insulation/damping materials).

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The tasks to be performed during Phase I include:

Estimated weights using historic data from similar vessels.

Calculated weights and centers of gravity (CG) from the 3D Model, scantling, and systems drawings.

Monitored and assessed weight and CG changes as design drawings were developed and supplier information was received.

Incorporated vendor/subcontractor furnished weight and center information.

Maintained a log of estimated vs. calculated vs. actual weight and center of gravity information.

B.3. Future Phase II Weight Control Tasks

The following will need to be performed during future design spirals:

During Detailed Design and Construction (DD&C) detailed weight and CG information will be extracted from the 3D Product Model. As the 3D Product Model is populated with structure and systems, weights and centers are extracted from the 3D Product Model by block or by system.

This is used in the weight report database yielding a high degree of accuracy. An example of the product model can be found in Figure 1.

Monitoring and assessing weights and CG as vessel construction will take place.

Quarterly Weight Reports will be prepared and submited.

Figure 1 Team LHG’s Production Design (ShipConstructor) – Model Illustrating Level of Detail

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Monitoring equipment weights from supplier drawings ensures that weight change is detected early so corrective actions can be taken and have little to no impact on the DD&C of the vessel. If the weight and margin values exceed the values specified in the Purchase Order or Purchase Technical Specifications, the suppliers will be required to take corrective action or incur liquidated damages.

C. RANGER IV WEIGHT CONTROL PLAN

The formal Weight Control Plan is based upon previous Team LHG weight control plans. Similar adaptations have been used successfully on other ships built within the Team LHG portfolio.

Team LHG has a demonstrated success record for accurate tracking of weight and KG during the DD&C process IAW the Society of Allied Weight Engineers recommended practices. Team LHG’s standard processes will be used to develop the RANGER IV specific Weight Control Plan which will then be followed throughout the project. The weight and VCG outcome of recent Team LHG programs is shown in Table 1 Team LHG history of Weight and VCG control.

TMC

Project

Baseline Weight

[LT]

VCG

[ft]

Inclined Weight

[LT]

VCG

[ft]

Weight Variance

[LT]

VCG

Variance

[ft] Result/Comment

Oman HSV 159 10.60 149.36 10.6 -5.79% 0.00% Actual weight is less than estimate due to unused builder’s margin.

MV Polaris

OSV

2,218 18.49 2,122 19.72 -4.31% 6.65% Actual weight is less than estimate due to unused design & build margin.

MV Regulus

OSV

2,122 19.72 2,156 19.72 1.60% 0.00% Weight increased due to change orders for the follow-on vessel

States Tide

OSV

2,748 22.93 2,748 22.93 -0.02% 0.00% Weight estimate correlated very well with the estimates.

Table 1 Team LHG history of Weight and VCG control

The objective of the WCP is to facilitate detection and reporting of any unsatisfactory weight and center of gravity trends during the design and construction (D&C) phases at the earliest possible time throughout those phases to enable Team LHG the widest choices of corrective actions. The WCP fully delineates procedures to be used in meeting the weight control responsibilities described in the contract.

Team LHG will present to the Government weight estimates and reports IAW the RANGER IV Specification. Each loading condition is estimated for ship delivery and at the end of service life. Weight and moment “Not-to-Exceed” (NTE) values with margins are identified and are those values where an increase in weight or moment would make the ship incapable of meeting its performance or Regulatory Body requirements, i.e., exceeding its stability criteria.

D. MONITORING WEIGHT GROWTH

The Team LHG WCT monitored weight and center of gravity throughout the preliminary design. The responsibility of RANGER IV contract margin control is as follows:

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Weight Margins: Team LHG is using a total D&C weight margin of 12%. These margins are fully within LHG’s responsibility to control and monitor through design and construction of the vessel.

o Through Preliminary/Contract Design: The RANGER IV design has been through four revisions. The current Contractor Design Weight Estimate (CDWE) (DI-030) is in the last stage of the design spiral. In the early design stage of RANGER IV lightship margin was 20% which was comprised of a 10% margin for Preliminary/Contract Design and 10% reserved for improvements in the design at the end of the four Design Reviews. The weight margin has been reduced from 20% to 12% as moved through the Design Reviews in the result of as vendor weights are being finalized and the design matures.

o Through Detail Design and Construction: During the transition from Functional/Class Design, the weight monitoring will transfer from hand calculation and estimates to extracting weight and center of gravity information from our 3D Product Model created using Ship Constructor or similar allowed software. At this point in the design process, we expect to have certified equipment weights from our equipment suppliers. During the DD&C phase a minimum 10% of lightship weight as the margin should be used. Here the shipyard will report to the Design Agent on proposed equipment changes before implementing them, and the agenent will ensure that there is no negative impact from the weights and CGs.

o Through Construction: The main emphasis during this phase will be verification of mill tolerance of steel and sampling equipment weights. The weight and center of gravity database will be updated to reflect the as built condition of the ship.

KG Margins: Team LHG used a total KG margin of 8% of the lightship at the first stage of design.

This margin was comprised of the 5% RANGER IV margin for Preliminary and Contract Design and a 3% margin for D&C. As a result of four design reviews and considering the current maturity of design KG Margin has reduced from 8% to 3%. These margins are fully within Team LHG’s responsibility to control and monitor through design and D&C of the vessel.

Service Life Allowance: 5 % of full load at delivery. This includes a 0.5 ft increase of the Full Load Vertical Centre of Gravity at delivery.

Material tolerances: The effect of variations in weight of materials and equipment from expected values shall be addressed during DD&C.

Weld Margin: The LHG Team uses a weld margin of 2.5% of the structural weight

E. MARGINS AND TRENDS

The RANGER IV weight and KG margins are IAW the RANGER IV Specification and are sufficient to support Functional/Class Design and Detail Design and Construction. Additionally, the processes employed by the LHG Team provide the necessary foresight throughout the project to continually aid in monitoring and controlling design weight estimates.

In the early design stage of RANGER IV was rated by SAWE Recommended Practice 14 as low risk due to total margin of 20% and Design Rating of 3 (Similar design with major changes/Some level of uncertainty).After design reviews of RANGER IV, it can be seen in Figure 2 , RANGER IV still can be rated by SAWE Recommended Practice 14 as low risk due to total margin of 12% and Design Rating of 5 (Follow design with minor changes/Almost no uncertainty).

In the early design stage of RANGER IV, our total KG margin of 8% was of moderate risk as defined by SAWE Recommend Practice 14 as moderate risk as seen in Figure 3 KG Risk Assessment. After four

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Figure 2 Weight Risk Assessment SAWE RP 14

Figure 3 KG Risk Assessment SAWE RP 14

RATING DESIGN CHARACTERIZATION

1 Developmental design/High level of uncertainty 2 New concept design/Some significant level of uncertainty 3 Similar design with major changes/Some level of uncertainty

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4 Similar design with minor changes/Little level of uncertainty 5 Follow design with minor changes/Almost no uncertainty

Table 2 Design Characterization Ratings SAWE RP 14

Margins were included as part of the Initial Weight Estimate and Revised Weight Report. Throughout D&C, the margin were adjusted concurrently to compensate for departures from the original estimate.

The margin adjustments were based on the results from calculations from detailed plans, 3D Model, and actual material/equipment weights.

The LHG Team submitted an updated CDWE with the changes tracked so that the contractor is held accountable by the contract reviewer in accordance with the DI-020 requirements. A sample CDWE which was developed based on the three-digit SWBS weight estimate can be seen below in Table 3 Sample Contractor Design Weight Estimate.

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Table 3 Sample Contractor Design Weight Estimate Summary

E.1. Adverse Trends in Weight Report

Adverse weight and KG trends can lead to compromises in payload and range, adverse effects on the performance, stability, maximum draft, and seakeeping of the vessel, none of which are acceptable. Thus, equipment weights were tracked against the allowance in the CDWE.

An increase in equipment weight was evaluated by the LHG Team as follows:

Prepared by: MCB Date: April 3, 2019

Project: TAI-1218 Checked by: CO/SC//KK/NK Date: 3 Apr 19 SUMMARY Drawing Number: DI-030 Revision: -

ESWBS Item Weight VCG V. MOM LCG L. MOM TCG T. MOM No. [LT] [ft] [LT.ft] [ft] [LT.ft] [ft] [LT.ft]

100 STRUCTURE 869.61 19.12 16,624.64 105.88 92,076.02 0.14 124.26

200 PROPULSION SYSTEMS 191.45 16.36 3,131.98 148.20 28,372.37 1.12 214.81

300 ELECTRICAL SYSTEMS 108.63 20.26 2,200.66 116.07 12,608.34 0.36 38.81

400 COMMAND & SURVEILLANCE 18.99 18.16 345.00 78.98 1,500.18 0.10 1.99

500 AUXILIARY SYSTEMS 286.01 23.72 6,782.76 113.77 32,538.25 0.51 147.14

600 OUTFIT & FURNISHINGS 203.48 27.22 5,539.62 103.32 21,023.60 -0.39 -78.48

700 ARMAMENT

- LIGHTSHIP ( W/O MARGINS) 1,678.17 20.63 34,624.67 112.10 188,118.76 0.27 448.54

DESIGN & BUILDING MARGIN

for WEIGHT (19% LS WEIGHT)

318.85 112.10 35,742.56 0.27 85.22

DESIGN & BUILDING MARGIN

for KG ( 7.8% LS KG)

1.61 513.14

CONTRACT MODIFICATION

MARGIN for WEIGHT (0.7% of LS & D&B Margin)

13.98 112.10 1,567.03 0.00 0.00

CONTRACT MODIFICATION

MARGIN for KG (0.5% of LS KG)

0.10 1.44

- LIGHT SHIP CONDITION Weight [LT] VCG [ft] V.MOM [LT.ft] LCG [ft] L.MOM [LT.ft] TCG [ft] T.MOM [LT.ft] 1,678.17 20.63 34,624.67 112.10 188,118.76 0.27 448.54

332.83 1.71 - 112.10 37,309.59 0.26 85.22

LIGHT SHIP CONDITION 2,011.00 22.34 44,935.60 112.10 225,428.36 0.27 533.77

SERVICE LIFE ALLOWANCE for WEIGHT (5% of FLC @

DELIVERY)

145.29 112.10 16,286.78 0.27 38.83

SERVICE LIFE ALLOWANCE for KG (0.5ft above FLC KG @

DELIVERY)

20.13

DI-030 - CONTRACTOR DESIGN WEIGHT ESTIMATE

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Early adverse weight changes will be evaluated to find alternative equipment or materials to minimize the weight and CG growth impact.

The supplier can correct the weight growth and not impact equipment or ship delivery - then they will proceed.

The supplier cannot or will not correct the weight growth – then Team LHG will adjust the DD&C margin and assess liquidated damages to the supplier in accordance with the terms of the

PO.

The associated weight growth is due to a bad estimate in the CDWE – then Team LHG will work with the supplier to see if the weight of the equipment can be reduced and adjust the D&C margin as required to compensate for the increase in weight.

As the design transitions into the DD&C phase, the contractor will have a relatively accurate structural weight and CG estimate from the 3D model we will create as the design matures. The contractor will have equipment items selected by make and model and will update estimated values with vendor supplier weight values. As the weight control plan transitions from a design weight control plan to a production weight control plan it will become more production oriented. Since the dimensional production is a derivative of the 3D model, the weight and center of gravity from detailed weight computations and NC tape drawings from the 3D model are incorporated in the weights computed. These "neat" structural weights derived from the 3D model are as close to actual as possible and will include the actual minimum usage weight. Suppliers and subcontractors of all larger machinery and outfit items will be asked to supply certified weights for their scope of supply. As the contractor goes through this process the weight estimate will become closer to the actual weight and the necessity for design margins will diminish.

F. RISK MITIGATION

Since the LHG Team started with a baseline weight estimate using a similar research vessel, and after recomputing and updating the weight and CG through the third RANGER IV design spiral, the vessel has a 12% total D&C weight margin. The risk associated with weight and KG growth is low as described in the previous Section E. Margins and Trends.

The WCP details the processes by which each of these risks were identified and managed. This ensures that a ship will meet all the requirements of the specification within the mass property limits specified in the Accepted Weight Estimate with a high degree of confidence.

G. REFERENCES

1. Society of Allied Weight Engineers Recommended Practice 12 Weight Control Technical Requirements for Naval Surface Ships Issue D (2002)

2. Society of Allied Weight Engineers Recommended Practice 14 Weight Estimating and Margin Manual for Marine Vehicles (2001)