DI-015_REV_2_MANEUVERING_PERFORMANCE_REPORT.pdf

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-015 Maneuvering Performance Report Revision 2

Submittal Date: July 24, 2024

DISTRIBUTION Statement C: Distribution authorized to the U.S. Government agencies and their Contractors. Other requests for this document shall be referred to the US Department of Transportation Volpe Center.

DATA RIGHTS: This report, drawing, design, concept, and specification are the intellectual property of Loch Harbour

Group, LLC, and/or R.R.P CONSULTING ENGINEERS, L.L.C and contain information which is proprietary. The rights defined below are reserved by Loch Harbour Group, LLC, and/or R.R.P CONSULTING ENGINEERS, L.L.C.

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.

Contract 6913G623P800007

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 2

TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

ACRONYMS AND ABBREVIATIONS

REVISION TABLE

SUBMISSION SUMMARY

A. MANEUVERABILITY STANDARDS AND CRITERIA

B. MANEUVERING PERFORMANCE

C. CONTROL SURFACES

D. COURSE KEEPING AND DIRECTIONAL STABILITY

E. CONCLUSION AND PREDICTION OF MANEUVERING PERFORMANCE

F. REFERENCES

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 3

LIST OF TABLES

Table 1 Ship Parameters Table 2 Summary of empirical results from Turning circle test Table 3 Stopping Track reach low and high boundaries Table 4 Control Surfaces

LIST OF FIGURES

Figure 1: Turning Circle Test Figure 2: STD/L vs. Rudder Angle Figure 3: Zig-zag maneuvering performance

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 4

ACRONYMS AND ABBREVIATIONS

ACRONYM DESCRIPTION

DRL Data Requirements List

SOW Statement of Work

DI Data Item

STD Steady turning diameter, ft

CB Block coefficient δR Rudder angle, degrees

B Max beam on WL, ft

L Length between perpendiculars, ft

Trim Vessel trim value, ft

Sp Span of rudder, ft

Ch Chord of rudder, ft

T Full load draft, ft

NR Number of rudders

VA Velocity of approach, kn

AB Submerged bow profile area

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 5

REVISION TABLE

REVISION DESCRIPTION DATE AUTHOR

0 Initial submission 01-12-2024 LHG

1 Updated as per Engineering Developments 06-19-2024 LHG

2 Updated to address Govt. comments 07-24-2024 LHG

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 6

SUBMISSION SUMMARY

This document is submitted by Loch Harbour Group, 3060 Williams Drive, Suite 510, Fairfax, Virginia 22031, to satisfy CLIN 00100 DI-015 Maneuvering Performance Report, of Contract No.

6913G623P800007.

The purpose of this report is to document the expected maneuvering performance.

The report includes:

• Proposal for implementing an independently operated high lift rudder system and a bow thruster for improved maneuverability characteristics, especially while docking and in tight harbors.

• Comparison of maneuvering characteristics between a conventional NACA rudder profile and a high lift rudder. The comparisons are shown for steady turning diameter, course keeping and directional stability (zigzags) over a range of ship speeds.

Government REVIEW and COMMENT of this report is REQUIRED.

The RANGER IV has been developed to be highly maneuverable and maintain excellent directional stability. The propulsion system is comprised of twin marine diesel engines with a

PTO/PTI propulsion system, twin rudders, and a bow thruster. A built in skeg provides additional lateral surface area and helps to keep directional stability.

A. MANEUVERABILITY STANDARDS AND CRITERIA

The maneuverability requirements as per Appendix B – NPS VOLPE Ranger IV Basis of Design requires Ranger IV to have two rudders, a through-hull bow thruster and be able to dock and undock without the use of tugs. Standardized ABS empirical formulations and linear approximations were used to estimate the following ship motions:

• Steady turning diameter.

• Stopping Track Reach.

• Course keeping (zigzags).

Preliminary/Contract Design of Motor Vessel Ranger IV

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 7

Table 1 describes the parameters from the current design that is used to empirically estimate the maneuvering characteristics of Ranger IV.

Table 1 Ship Parameters

Parameter Value Unit

Cb Block Coefficient 0.56 -𝜹𝑹 Rudder angle 35 deg

Trim Trim 0

L Length of Waterline/LBP 175’ / 162' ft

B Molded breadth 36’-0” ft

Sp Span of Rudder 5’-10” ft

Ch Mean chord 4’-2 4/5” ft

T Design draft 9’-0” ft

ST Stern type 2 -

TL Draft 9’-0” ft

AB Submerged bow profile area 34.6 ft2

Vs Test speed 15 knots

*Note that the submerged bow profile area (AB)is negative due to the bow shape of the RANGER IV, as it is projected aft of the forward perpendicular. This contrasts with vessels with a bulbous bow, in which the value of AB is positive, as the submerged bow profile area is projected forward of the forward perpendicular.

Empirical formulations are used as they are capable of providing insight into the maneuvering performance using limited amount of input data. Due to the complexity of hydrodynamics involved in vessel maneuvering, the accuracy of empirical methods is limited, and the following results must be considered as approximate guidance. This report further elaborates on the control surfaces expected to be used onboard Ranger IV and predicts the maneuvering performance of the vessel.

B. MANEUVERING PERFORMANCE

The method used to estimate the elements of Turning Circle are taken from the ABS Guide for

Vessel Maneuverability - February 2017. While the method is limited to single-screw monohulls, it may be used as an initial indicator of performance. Ranger IV is expected to have better handling characteristics than what is estimated due to her twin high-lift type rudders.

The turning ability of a vessel is a measure of the ability to turn the vessel using a hard-over rudder, the result being a minimum “advance at 90° change of heading” and “tactical diameter” defined by the “transfer at 180° change of heading”. The rudder angle is executed following a steady approach with zero yaw rate. FIGURE-1 illustrates the measures as described.

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 8

Figure 1: Turning Circle Test.

The steady turning diameter (STD) is calculated using the below formula:

𝑺𝑻𝑫

𝑳 = 𝟒. 𝟏𝟗 − 𝟐𝟎𝟑

𝑪𝑩

𝜹𝑹

+ 𝟒𝟕. 𝟒 𝑻𝒓𝒊𝒎

𝑳

𝟏𝟑. 𝟎𝑩

𝑳

𝟏𝟗𝟒 𝜹𝑹

− 𝟑𝟓. 𝟖 𝑺𝒑. 𝑪𝒉

𝑳. 𝑻

(𝑺𝑻 − 𝟏) + 𝟑. 𝟖𝟐

𝑺𝒑. 𝑪𝒉

𝑳. 𝑻

(𝑺𝑻 − 𝟐)

+ 𝟕. 𝟕𝟗

𝑨𝑩

𝑳. 𝑻 + 𝟎. 𝟕 (

𝑻

𝑻𝑳

− 𝟏) ( 𝜹𝑹

|𝜹𝑹|

) (𝑺𝑻 − 𝟏)

Ranger IV is estimated to have a steady turning diameter of under 3 ship lengths at 35 degrees rudder angle initiated at a speed of 14 knots at the full load draft. The RRP Team recognizes that this equation was developed based on the premise that a conventional rudder system characterizes the propulsion system. All ship parameters are indicative of vessel particulars of the RANGER IV, except for the rudder span (Sp) and rudder chord (Ch). The rudder span (SP) and rudder chord

(Ch) designations are approximate values of nominal rudder sizes for a vessel of this size.

Furthermore, ABS Guide for Maneuverability 2017, Appendix 4 illustrates the Empirical techniques to estimate the maneuvering parameters that are limited for twin screw configuration.

The formulae mentioned in ABS guide, is applicable is the single screw monohull, whereas

RANGER IV has a twin-screw twin rudder configuration. However, the installed system is a twin-screw propulsion system with a high lift rudder which will outperform a conventional rudder. Any actual performance is estimated to be superior to the empirically estimated performance.

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 9

Figure 2: STD/L vs. Rudder Angle

Advance, Tactical Diameter, Transfer, and the Velocity in Turn, as described earlier are also estimated empirically from the ABS formulation and are calculated as follows:

• Tactical Diameter:

𝑻𝑫

𝑳 = 𝟎. 𝟗𝟏𝟎

𝑺𝑻𝑫

𝑳 + 𝟎. 𝟒𝟐𝟒

𝑽𝑺

√𝑳 + 𝟎. 𝟔𝟕𝟓

• Advance:

𝑨𝒅

𝑳 = 𝟎. 𝟓𝟏𝟗

𝑻𝑫

𝑳 + 𝟏. 𝟑𝟑

• Transfer:

𝑻𝒓

𝑳 = 𝟎. 𝟒𝟗𝟕

𝑻𝑫

𝑳 − 𝟎. 𝟎𝟔𝟓

• Velocity in turn:

𝑽𝑻

𝑽𝑺

= 𝟎. 𝟎𝟕𝟒

𝑻𝑫

𝑳 + 𝟎. 𝟏𝟒𝟗

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00

R u d d er A n gl e

D el ta R

D eg re es

STD/L

STD/L vs Delta R

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 10

The results obtained for varying rudder angles are provided in Table 2 Summary of empirical results from Turning circle below.

Table 2 Summary of empirical results from Turning circle test.

Rudder

Angle STD/L TD/L Ad/L Tr/L Vt/Vs

10 8.68 9.41 6.21 4.61 0.85

20 4.67 5.75 4.32 2.79 0.57

30 3.33 4.53 3.68 2.19 0.48

40 2.66 3.92 3.37 1.89 0.44

50 2.26 3.56 3.18 1.70 0.41

60 1.99 3.32 3.05 1.58 0.39

70 1.80 3.14 2.96 1.50 0.38

The results at 30°, 40°, 50°, 60°, and 70° “apparent” rudder angles are presented to give an idea of the STD, TD, Ad, Tr, and Vt for the enhanced range of motion that the high lift rudder will provide.

For any vessel, the longest stopping distance can be assumed to result when the vessel travels in a straight line along the original course, after the astern order is given. The stopping track reach of

Ranger IV is estimated in the number of ship lengths as follows:

𝑆𝑙𝑜𝑤 = 𝐴𝑙𝑜𝑤𝑙𝑜𝑔𝑒(1 + 𝐵𝑙𝑜𝑤) + 𝐶

𝑆ℎ𝑖𝑔ℎ = 𝐴ℎ𝑖𝑔ℎ𝑙𝑜𝑔𝑒(1 + 𝐵ℎ𝑖𝑔ℎ) + 𝐶

Where, 𝑆𝑙𝑜𝑤 , 𝑆ℎ𝑖𝑔ℎ = 𝑆𝑡𝑜𝑝𝑝𝑖𝑛𝑔 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒, 𝑖𝑛 𝑠ℎ𝑖𝑝 𝑙𝑒𝑛𝑔𝑡ℎ𝑠

𝐴𝑙𝑜𝑤 , 𝐴ℎ𝑖𝑔ℎ = 𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑑𝑒𝑝𝑒𝑛𝑑𝑎𝑛𝑡 𝑜𝑛 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑡ℎ𝑒 𝑣𝑒𝑠𝑠𝑒𝑙 𝑑𝑖𝑣𝑖𝑑𝑒𝑑 𝑏𝑦 𝑟𝑒𝑠𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡

𝐶𝑙𝑜𝑤 , 𝐶ℎ𝑖𝑔ℎ = 𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑑𝑒𝑝𝑒𝑛𝑑𝑎𝑛𝑡 𝑜𝑛 𝑣𝑒𝑠𝑠𝑒𝑙 𝑟𝑒𝑠𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑑𝑖𝑣𝑖𝑑𝑒𝑑 𝑏𝑦 𝑎𝑠𝑡𝑒𝑟𝑛 𝑡ℎ𝑟𝑢𝑠𝑡

𝐶 = 𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑑𝑒𝑝𝑒𝑛𝑑𝑒𝑛𝑡 𝑜𝑛 𝑝𝑟𝑜𝑑𝑢𝑐𝑡 𝑜𝑓 𝑡𝑖𝑚𝑒 𝑡𝑜 𝑎𝑐ℎ𝑖𝑒𝑣𝑒 𝑎𝑠𝑡𝑒𝑟𝑛 𝑡ℎ𝑟𝑢𝑠𝑡 𝑎𝑛𝑑 𝑖𝑛𝑡𝑖𝑎𝑙 𝑠𝑝𝑒𝑒𝑑 𝑜𝑓 𝑣𝑒𝑠𝑠𝑒𝑙

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 11

Table 3 Stopping Track reach low and high boundaries.

Parameter In ship lengths In meters

S low 6.06 311.36

S high 8.54 438.70

The results for boundaries of stopping distances are presented in Table 3 to give an idea of stopping capability which is between 6L and 8L (where L is ship’s LBP).

In addition to the conventional stopping distance by reversing the propeller, the stopping distance can be further reduced significantly by swinging the two independent rudders outboard to the full

40̊ acting as a brake.

C. CONTROL SURFACES

Controls surfaces and systems of the RANGER IV that contribute to maneuvering performance

(both active and passive) are listed in Table 4.

Table 4 Control Surfaces

Control Surfaces and Systems TYPE

High Lift Type Rudder Active

Bow Thruster Active

Bilge Keels Passive

Skeg Passive

At present, the locations, and relative sizes of the bilge keels and skeg have been investigated by empirical methods and are largely based on technical adaptations from the parent vessel and other similar ships. A flow visualization on the bilge keels was performed doing the scaled model tests to minimize hull drag from the bilge keels.

D. COURSE KEEPING AND DIRECTIONAL STABILITY

As the RANGER IV is equipped with two Propellers, two high lift rudders, skeg, and a bow thruster system. A preliminary estimate of directional stability has been carried out using linear approximations as shown below:

Use or disclosure of the data contained on this sheet is subject to the restriction on the title page of this document. 12

Figure 3: Zigzag maneuvering performance.

As per the ABS Guide for Maneuverability, section 2-1, Table 1, it is to be noted that the residual turning rate and the width of instability loop, which are both a measure of Straight-line Stability and Course Keeping Ability are not rated by ABS.

In the preliminary comparison, high-lift rudders have shown significant improvement in the turning radius and overshoot angles, which further increases confidence and reliability in the overall controllability of RANGER IV in tight operational spaces at Lake Superior docks.

E. CONCLUSION AND PREDICTION OF MANEUVERING PERFORMANCE

Utilizing high lift rudders, the RANGER IV design will meet all maneuvering performance requirements. The RANGER IV will be directionally stable across all loading conditions and in the zig-zag maneuver over the full range of ship speeds.

F. REFERENCES

1. ABS Guide for Vessel Maneuverability. March 2006 (Updated February 2017)

-150

-100

-50

-100 0 100 200 300 400 500 600 700 y-co o rd in at e (f t) x-coordinate (ft)

10 Degrees Zig-Zag 20 degrees Zig-Zag