Mooring_Towing Foundation.pdf
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- TUGCON Voyage Charter Federal contract opportunity
- Solicitation number
- N3220525R4075
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This document is a detailed technical report for the Mooring and Towing Foundation Calculations for a US Navy YRBM (Yard Repair Boat Miscellaneous) barge, prepared by Conrad Shipyard. The report comprehensively analyzes the structural foundations for various mooring and towing equipment, including double bitts, kevel chocks, panama chocks, and towing padeyes. The calculations use BeamPro software to evaluate the strength and load-bearing capabilities of different beam and header configurations, ensuring they can withstand expected forces from equipment with safe working loads ranging from 110 to 205 kips. The analysis covers multiple locations on the barge (bow, stern, midship, side shell) and systematically checks section modulus, shear stress, and other structural integrity metrics using ABS Grade A steel with specific yield and stress allowances.
The report details proposed modifications to longitudinal stiffeners and headers to reinforce the deck structure, such as replacing standard L 4x3x1/4" stiffeners with more robust flange plate headers like FP 15x5x3/8" or FP 14x4x3/8" to support the mooring and towing equipment. Each location receives individualized analysis, with calculations showing the proposed structures pass required strength checks. The document is part of the design and engineering process for Conrad Shipyard's Contract N00024-22-C-2253, specifically for a US Navy YRBM barge identified as Hull C1401, with the calculations serving as a critical component of the vessel's structural design validation.
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Other files for this federal contract opportunity
| File | Type | Posted |
|---|---|---|
| Mooring_Towing Arrangement.pdf | ||
| Topside Arrangement.pdf | ||
| General Arrangement.pdf | ||
| 25R4075 RFP.pdf | ||
| Towing Procedures.pdf | ||
| 2015-0213 Rev. 37.pdf |
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Distribution Statement C: Distribution authorized to U.S. Government agencies and their U.S.
contractors only; Proprietary Information; 3/15/2022. Other requests for this document shall be referred to NAVAL SEA SYSTEM COMMAND (NAVSEA) PMS 325
WARNING- This document contains technical data whose export is restricted by the Arms Export Control Act (Title 22, U.S.C. Sec 2751 et seq.) or the Export Administration Act of 1979, as amended, Title 50, U.S.C., App 2401, et seq. Violations of these export laws are subject to severe criminal penalties. Disseminate per provisions of OPNAVINST 551 0.161, Withholding of Unclassified Technical Data from Public Disclosure, 29 July 1985
Conrad Shipyard | N00024-22-C-2253 DI-026-36 | C1401-180-R1 | Rev A
US NAVY YRBM
DI-026-36 | C1401-180-R1 | Rev A
MOORING AND TOWING FOUNDATION
CALCULATIONS
Prepared: Sophia Cerrone
Reviewed by: Collin Thibodeaux
MOORING AND TOWING FOUNDATION CALCULATIONS
Conrad Shipyard, LLC. | Page 1 of 48
REVISION TABLE
Revision Revision Description Revision Date
- Initial Issue 5 MAY 2022 A Revised Bow Chock Foundation Design 21 JULY 2022
HULL APPLICABILITY TABLE
Conrad Hull Number USN Hull Number
1 C1401 YRBM 57
Conrad Shipyard, LLC. | Page 2 of 48
Table of Contents References
1 Introduction
2 Calculation Notes
3 Nabrico DF-491 Double Bitt Foundation Calculations
3.1. Bow Location
3.2. Stern Location
4 Nabrico DF-40 Double Bitt Foundation Calculation
5 Nabrico DF-482 Kevel Chock Foundation Calculations
5.1. Forward and Aft Locations
5.2. Midship Location
6 Panama Chock Foundation Calculation
6.1. Bow Location
6.2. Stern Location
6.3. Side Shell Locations
7 Longitudinal Stiffener Checks
7.1. Starboard Bow Longitudinal Stiffener Check
7.2. Port Bow Longitudinal Stiffener Check
7.3. Stern Longitudinal Stiffener Check
7.4. Port Stern Longitudinal Stiffener Check
8 Towing Padeye Foundation Calculations
References
No. References DWG Number References DWG Title Revision
1 C1401-110-F1 Hull Scantling Plan - 2 C1401-582-F1 Mooring and Towing Arrangement & Details A
Conrad Shipyard, LLC. | Page 3 of 48
1 Introduction The purpose of this report is to present the results of the foundation analyses for all mooring and towing equipment on board Conrad Hull C1401, an accommodation YRBM barge for the US Navy.
2 Calculation Notes Beam calculations using BeamPro software were done to size all the underdeck foundations for the mooring and towing equipment. All BeamPro results are presented in pounds (lbs) and inches (in).
In some places, headers or members are slightly oversized for the required SM. This is because uniform solutions which could be used across the entire barge were prioritized. This was done to keep the number of different parts and details to a minimum.
All supporting members were assumed to be ABS Grade A steel with a yield strength of 34 ksi. The maximum allowable bending stress used was 20.4 ksi, and the maximum allowable shear stress used was 13.6 ksi.
Conrad Shipyard, LLC. | Page 4 of 48
3 Nabrico DF-491 Double Bitt Foundation Calculations
Figure 1 Nabrico 12” DF-491 Double Bitt
The 12” double bitt, as shown in Figure 1, has a safe working load of 205 kips. The pull height of the double bitt is 15.25 inches above the deck. The base is 60 inches long and 18 inches wide. The load was assumed to be applied in the longitudinal direction, and the overturning moment calculation can be found below, in Figure 2.
Figure 2 Overturning Moment Calculation
Two 12” bitts are located on deck, one each on the bow and the stern of the barge. Separate analysis was conducted for both locations, due to differing orientations.
Safe Working Load = 205,000 lbs
15.250 in
3,126,250 lb-in
3,126,250 lb-in
60.000 in
52,104 lbs
52,104 lbs
Width of Base =
Force Couple = Number of Beams =
Force Per Beam (1 Beam) =
Height of Bitt from Deck =
Maximum Overturning Moment =
Force Couple =
Calculate the Max Overturning Moment of the Double Bitt:
Calculate the Force on Member due to Max Overturning Moment:
F = Max Overturning Moment / Distance Between Feet
Conrad Shipyard, LLC. | Page 5 of 48
3.1. Bow Location
The proposed foundation structure for the bow double bitt consists of a single FP 14x4x3/8” header that spans diagonally under the entire length of the equipment and attached to a longitudinal stiffener and a NT bulkhead, as seen in Figure 3.
Figure 3 Bow 12” Double Bitt & Proposed Support Structure (Frs. 1-3)
The calculations used to determine the size of the foundation can be found in the following pages.
Figure 4 BeamPro Loading Diagram
Figure 5 BeamPro Shear Diagram
Conrad Shipyard, LLC. | Page 6 of 48
Figure 6 BeamPro Bending Moment Diagram
Figure 7 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 6 is 15.3 in³. The proposed header has 39.5 in³ available. The required shear area based on the maximum shear force in Figure 5 is 3.09 in², and the proposed header has 5.39 in² available. The sections properties and stress results can be found in Figure 8.
Conrad Shipyard, LLC. | Page 7 of 48
Figure 8 Section Properties and Stress Results
The NT bulkhead was assumed to have enough strength to support the reactionary force of the header.
Analysis regarding the supporting longitudinal stiffener can be found in Section 7.1 of this report.
0.375 in ABS Grade A Flange Plate ABS Grade A FP 14x4x3/8"
74.56 in
24.00 in
9.32 in (L/8)
FP 14x4x3/8"
13.63 in
0.38 in
4.00 in
0.38 in
14.38 in
417.089 in4
109.067 in3
39.531 in3
15.609 in2
5.391 in2
5.17 in 14.42
312,121 lb-in 312.12 kip-in 41,952 lbs 41.95 kips
34 ksi
20.4 ksi
15.300 in3
PASS
34 ksi
13.6 ksi
3.085 in2
PASS
Allowable Shear Stress = Required Shear Area =
Shear Area Check
Fy = Allowable Bending Stress =
Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress Fy =
Web Thick: TW
Required SM = Max Moment / Allowable Bending Stress
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange = Area of Section =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Maximum Moment = Max Shear Force =
Flange Width: Bf
Spacing of Beam Effective Width
Size Web Depth: DW
Bow Deck Header
Plate Thickness Structure Type
Flange Plate Size Length of Beam
Conrad Shipyard, LLC. | Page 8 of 48
3.2. Stern Location
The proposed foundation structure for the stern double bitt consists of a single transverse FP 14x4x3/8” header that concludes at the NT bulkhead, as seen in Figure 9.
Figure 9 Stern 12” Double Bitt & Proposed Support Structure (Fr. 75)
The calculations used to determine the size of the foundation can be found on the following pages.
Figure 10 BeamPro Loading Diagram
Figure 11 BeamPro Shear Diagram
Conrad Shipyard, LLC. | Page 9 of 48
Figure 12 BeamPro Bending Moment Diagram
Figure 13 BeamPro Bending Moment Diagram
The required SM based on the maximum bending moment in Figure 12 is 34.5 in³. The proposed header has 39.5 in³ available. The required shear area based on the maximum shear force in Figure 11 is 2.87 in². The proposed header has 5.39 in² available. The sections properties and stress results can be found in Figure 14.
Conrad Shipyard, LLC. | Page 10 of 48
Figure 14 Section Properties and Stress Results
The NT bulkhead was assumed to have enough strength to support the reactionary force of the header.
Analysis regarding the supporting longitudinal stiffener can be found in Section 7.2 of this report.
0.375 in ABS Grade A Flange Plate ABS Grade A FP 14x4x3/8"
72.00 in
24.00 in
9.00 in (L/8)
FP 14x4x3/8"
13.63 in
0.38 in
4.00 in
0.38 in
14.38 in
417.089 in4
109.067 in3
39.531 in3
15.609 in2
5.391 in2
5.17 in 13.93
703,404 lb-in 703.40 kip-in 39,078 lbs 39.08 kips
34 ksi
20.4 ksi
34.481 in3
PASS
34 ksi
13.6 ksi
2.873 in2
PASS
Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress Fy =
Allowable Shear Stress = Required Shear Area =
Shear Area Check
Maximum Moment =
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange = Area of Section =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Stern Deck Header
Plate Thickness Structure Type
Flange Plate Size Length of Beam Spacing of Beam Effective Width
Size Web Depth: DW
Conrad Shipyard, LLC. | Page 11 of 48
4 Nabrico DF-40 Double Bitt Foundation Calculation
Figure 15 Nabrico 10” DF-40 Double Bitt
The 10” double bitt, as shown in Figure 15, has a safe working load of 127 kips. The pull height of the double bitt is 10.125 inches above the deck. The base is 45 inches long and 15 inches wide. The load was found below, in Figure 16.
Figure 16 Overturning Moment Calculation
Safe Working Load = 127,000 lbs
10.125 in
1,285,875 lb-in
1,285,875 lb-in
45.000 in
28,575 lbs
28,575 lbs
Width of Base =
Force Couple = Number of Beams =
Force Per Beam (1 Beam) =
Height of Bitt from Deck =
Maximum Overturning Moment =
Force Couple =
Calculate the Max Overturning Moment of the Double Bitt:
Calculate the Force on Member due to Max Overturning Moment:
F = Max Overturning Moment / Distance Between Feet
Conrad Shipyard, LLC. | Page 12 of 48
The proposed foundation structure can be seen in Figure 17, where the entirety of the load is placed on the longitudinal stiffener that spans between two NT bulkheads. The typical stiffener size of L 4x3x1/4” does not provide enough section modulus to support the force of the double bitt, so a FP 14x4x3/8” header is suggested to replace the stiffener for the 6’-0” span.
Figure 17 Stbd Aft 10” Double Bitt & Proposed Support Structure (Frs. 61-65)
Figure 18 BeamPro Loading Diagram
Figure 19 BeamPro Shear Diagram
Figure 20 BeamPro Bending Moment Diagram
Conrad Shipyard, LLC. | Page 13 of 48
Figure 21 BeamPro Defelction Diagram
The required SM based on the maximum bending moment in Figure 20 is 11.87 in³. The header has 39.5 in³ available. The required shear area based on the maximum shear force in Figure 19 is 1.31 in². The header has 5.39 in² available. The sections properties and stress results can be found in Figure 22.
Conrad Shipyard, LLC. | Page 14 of 48
Figure 22 Section Properties and Stress Results
The NT bulkheads were assumed to have enough section modulus and shear stress to support the header.
0.375 in ABS Grade A Flange Plate ABS Grade A FP 14x4x3/8"
72.00 in
24.00 in
9.00 in (L/8)
FP 14x4x3/8"
13.63 in
0.38 in
4.00 in
0.38 in
14.38 in
417.089 in4
109.067 in3
39.531 in3
15.609 in2
5.391 in2
5.17 in 13.93
242,173 lb-in 242.17 kip-in 17,859 lbs 17.86 kips
34 ksi
20.4 ksi
11.871 in3
PASS
34 ksi
13.6 ksi
1.313 in2
PASS
Allowable Shear Stress = Required Shear Area =
Shear Area Check
Fy =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Maximum Moment = Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress
Area of Section =
Effective Width
Size Web Depth: DW
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange =
Spacing of Beam
Port & Stbd Midbody Deck Header
Plate Thickness Structure Type
Conrad Shipyard, LLC. | Page 15 of 48
5 Nabrico DF-482 Kevel Chock Foundation Calculations
Figure 23 Nabrico 36” DF-482 Kevel Chock
The 36” kevel chock, as shown in Figure 23, has a safe working load of 185 kips. The pull height of the kevel is 2.19 inches above the deck. The base is 23.5 inches long and 11 inches wide. The load was found below, in Figure 24
Figure 24 Longitudinal Overturning Moment Calculation
Safe Working Load = 185,000 lbs
2.188 in
404,688 lb-in
404,688 lb-in
23.500 in
17,221 lbs
17,221 lbs
LONGITUDINAL
Force Couple =
Calculate the Max Overturning Moment of the Kevel:
Calculate the Force due to Max Overturning Moment:
F = Max Overturning Moment / Distance Between Feet
Height of Kevel from Deck =
Maximum Overturning Moment =
Width of Base =
Force Couple = Number of Beams =
Force Per Beam (1 Beam)=
Conrad Shipyard, LLC. | Page 16 of 48
6 kevels are located on deck, two forward, two midbody, and two aft. Separate analysis was also conducted for the forward/aft and the midbody locations, due to differing underdeck structure.
5.1. Forward and Aft Locations
The proposed foundation structure can be seen in Figure 25, where the load is placed on a single 4-ft long L 6x4x5/16” longitudinal header that spans between two bulkheads. A ½” doubler plate was also assumed to add strength to the foundation.
Figure 25 Stbd Fwd 36” Kevel & Proposed Support Structure (Frs. 10-12), Aft and Port Structure Similar
The calculations used to determine the foundation can be found on the following pages.
Figure 26 BeamPro Loading Diagram
Conrad Shipyard, LLC. | Page 17 of 48
Figure 27 BeamPro Shear Diagram
Figure 28 BeamPro Bending Moment Diagram
Figure 29 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 28 is 5.063 in³. The proposed header has 11.4 in³ available. The required shear area based on the maximum shear force in Figure 27 is
0.646 in². The header has 2.15 in² available. The sections properties and stress results can be found in Figure 30.
Conrad Shipyard, LLC. | Page 18 of 48
Figure 30 Section Properties and Stress Results
The WT and NT bulkheads were assumed to have enough section modulus and shear stress to support the header.
0.875 in ABS Grade A Angle ABS Grade A
L 6x4x5/16"
48.00 in
24.00 in
6.00 in (L/8)
L 6x4x5/16"
5.69 in
0.31 in
4.00 in
0.31 in
6.88 in
66.802 in4
66.338 in3
11.384 in3
24.027 in2
2.148 in2
1.67 in 28.79
103,285 lb-in 103.28 kip-in 8,783 lbs 8.78 kips
34 ksi
20.4 ksi
5.063 in3
PASS
34 ksi
13.6 ksi
0.646 in2
PASS
Spacing of Beam
Fwd & Aft Kevel Deck Header
Plate Thickness Structure Type
Angle Size Length of Beam
Area of Section =
Effective Width
Size Web Depth: DW
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange =
Fy =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Maximum Moment = Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress
Allowable Shear Stress = Required Shear Area =
Shear Area Check
Conrad Shipyard, LLC. | Page 19 of 48
5.2. Midbody Location
The proposed foundation structure can be seen in Figure 31, where the load is placed on a single 6-ft L 6x4x5/16” longitudinal header that spans between two NT bulkheads. A ½” doubler plate was also assumed to add strength to the foundation.
Figure 31 Stbd Midship 36” Kevel & Proposed Support Structure (Fr. 30-34), Port Structure Similar
Figure 32 BeamPro Loading Diagram
Figure 33 BeamPro Shear Diagram
Conrad Shipyard, LLC. | Page 20 of 48
Figure 34 BeamPro Bending Moment Diagram
Figure 35 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 34 is 10.0 in³. The proposed header has 11.38 in³ available. The required shear area based on the maximum shear force in Figure 33 is 0.853 in². The header has 2.15 in² available. The sections properties and stress results can be found in Figure 36.
Conrad Shipyard, LLC. | Page 21 of 48
Figure 36 Section Properties and Stress Results
The NT bulkheads were assumed to have enough section modulus and shear stress to support the header.
0.875 in ABS Grade A Angle ABS Grade A
L 6x4x5/16"
72.00 in
24.00 in
9.00 in (L/8)
L 6x4x5/16"
5.69 in
0.31 in
4.00 in
0.31 in
6.88 in
66.802 in4
66.338 in3
11.384 in3
24.027 in2
2.148 in2
1.67 in 43.18
203,869 lb-in 203.87 kip-in 11,595 lbs 11.60 kips
34 ksi
20.4 ksi
9.994 in3
PASS
34 ksi
13.6 ksi
0.853 in2
PASS
Spacing of Beam
Midbody Kevel Deck Header
Plate Thickness Structure Type
Angle Size Length of Beam
Area of Section =
Effective Width
Size Web Depth: DW
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange =
Fy =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Maximum Moment = Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress
Allowable Shear Stress =
Conrad Shipyard, LLC. | Page 22 of 48
6 Panama Chock Foundation Calculation
Figure 37 Nabrico DF-531 Panama Chock
The 14x10” panama chock, as shown in Figure 37, has a safe working load of 110.32 kips. The pull height of the chock is 16.5 inches above the deck. The base is 28 inches long and 14 inches wide. The load was found in Figure 38.
Figure 38 Overturning Moment Calculation
Separate analysis was conducted for the bow and stern chocks, due to differing locations on the headers.
Safe Working Load = 110,230 lbs
16.500 in
1,818,795 lb-in
1,818,795 lb-in
28.000 in
64,957 lbs
64,957 lbs
Calculate the Max Overturning Moment of the Chock:
Calculate the Force due to Max Overturning Moment:
F = Max Overturning Moment / Distance Between Feet
Force Per Beam (2 Beams) =
Width of Base =
Force Couple = Number of Beams =
Height of Bitt from Deck =
Maximum Overturning Moment =
Force Couple =
Conrad Shipyard, LLC. | Page 23 of 48
6.1. Bow Location
The proposed foundation structure for the bow chocks consists of a single transverse header that spans between the centerline bulkhead and a longitudinal stiffener, as seen in Figure 39. A ½” doubler plate was also assumed to increase foundation strength.
Figure 39 Stbd Bow Chock & Proposed Support Structure (Fr 0-1), Port Side Similar
Figure 40 BeamPro Loading Diagram
Figure 41 BeamPro Shear Diagram
Figure 42 BeamPro Bending Moment Diagram
Conrad Shipyard, LLC. | Page 24 of 48
Figure 43 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 42 is 35.1 in³. The proposed header has 43.0 in³ available. The required shear area based on the maximum shear force in Figure 41 is 2.5 in².
The header has 5.58 in² available. The sections properties and stress results can be found in Figure 44.
Conrad Shipyard, LLC. | Page 25 of 48
Figure 44 Section Properties and Stress Results
The centerline bulkhead was assumed to have enough section modulus and shear stress to support the headers. Analysis regarding the supporting longitudinal stiffeners can be found in Section 7 of this report.
0.875 in ABS Grade A Flange Plate ABS Grade A FP 14x4x3/8"
48.00 in
24.00 in
6.00 in (L/8)
FP 14x4x3/8"
13.63 in
0.38 in
4.00 in
0.38 in
14.88 in
529.950 in4
207.549 in3
43.010 in3
27.609 in2
5.578 in2
4.38 in 10.96
716,814 lb-in 716.81 kip-in 33,940 lbs 33.94 kips
34 ksi
20.4 ksi
35.138 in3
PASS
34 ksi
13.6 ksi
2.496 in2
PASS
Spacing of Beam
Bow Chock Headers
Plate Thickness Structure Type
Flange Plate Size Length of Beam
Area of Section =
Effective Width
Size Web Depth: DW
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange =
Fy =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Maximum Moment = Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress
Allowable Shear Stress =
Conrad Shipyard, LLC. | Page 26 of 48
6.2. Stern Location
The proposed foundation structure for the stern chocks is identical to the bow chocks; a single transverse header that spans between the centerline bulkhead and a longitudinal stiffener, as seen in Figure 45. A ½” doubler plate was also assumed to increase foundation strength.
Figure 45 Stbd Stern Chock & Proposed Support Structure, Port Structure Similar
Figure 46 BeamPro Loading Diagram
Figure 47 BeamPro Shear Diagram
Conrad Shipyard, LLC. | Page 27 of 48
Figure 48 BeamPro Bending Moment Diagram
Figure 49 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 48 is 34.1 in³. The proposed header has 43.0 in³ available. The required shear area based on the maximum shear force in Figure 47 is 2.5 in².
The header has 5.58 in² available. The sections properties and stress results can be found in Figure 50.
Conrad Shipyard, LLC. | Page 28 of 48
Figure 50 Section Properties and Stress Results
The centerline bulkhead was assumed to have enough section modulus and shear stress to support the headers. Analysis regarding the supporting longitudinal stiffeners can be found in Section 7 of this report.
0.875 in ABS Grade A Flange Plate ABS Grade A FP 14x4x3/8"
48.00 in
24.00 in
6.00 in (L/8)
FP 14x4x3/8"
13.63 in
0.38 in
4.00 in
0.38 in
14.88 in
529.950 in4
207.549 in3
43.010 in3
27.609 in2
5.578 in2
4.38 in 10.96
696,450 lb-in 696.45 kip-in 33,940 lbs 33.94 kips
34 ksi
20.4 ksi
34.140 in3
PASS
34 ksi
13.6 ksi
2.496 in2
PASS
Spacing of Beam
Stern Chock Headers
Plate Thickness Structure Type
Flange Plate Size Length of Beam
Area of Section =
Effective Width
Size Web Depth: DW
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange =
Fy =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Maximum Moment = Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress
Allowable Shear Stress =
Conrad Shipyard, LLC. | Page 29 of 48
6.3. Side Shell Locations
The proposed foundation structure for the side shell chocks consists of a single longitudinal header that spans between two bulkheads, as seen in Figure 51. A ½” doubler plate was also assumed to increase foundation strength.
Figure 51 Stbd Side Shell Chock & Proposed Support Structure, Port Side Similar
Figure 52 BeamPro Loading Diagram
Figure 53 BeamPro Shear Diagram
Conrad Shipyard, LLC. | Page 30 of 48
Figure 54 BeamPro Bending Moment Diagram
Figure 55 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 54 is 39.26 in³. The proposed header has 43.01 in³ available. The required shear area based on the maximum shear force in Figure 53 is 3.11 in². The header has 5.58 in² available. The sections properties and stress results can be found in Figure 56.
Conrad Shipyard, LLC. | Page 31 of 48
Figure 56 Section Properties and Stress Results
The bulkheads were assumed to have enough section modulus and shear stress to support the headers.
Analysis regarding the supporting longitudinal stiffeners can be found in Section 7 of this report.
0.875 in ABS Grade A Flange Plate ABS Grade A FP 14x4x3/8"
72.00 in
24.00 in
9.00 in (L/8)
FP 14x4x3/8"
13.63 in
0.38 in
4.00 in
0.38 in
14.88 in
529.950 in4
207.549 in3
43.010 in3
27.609 in2
5.578 in2
4.38 in 16.43
800,985 lb-in 800.98 kip-in 42,330 lbs 42.33 kips
34 ksi
20.4 ksi
39.264 in3
PASS
34 ksi
13.6 ksi
3.113 in2
PASS
Allowable Shear Stress = Required Shear Area =
Shear Area Check
Fy =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Maximum Moment = Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress
Area of Section =
Effective Width
Size Web Depth: DW
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange =
Spacing of Beam
Side Shell Chock Headers
Plate Thickness Structure Type
Conrad Shipyard, LLC. | Page 32 of 48
7 Longitudinal Stiffener Checks Analysis of the 4x3x1/4” deck longitudinal stiffeners was performed to ensure there was adequate strength to support the reactionary forces of the bow and stern double bitt and chock transverse headers, respectively.
7.1. Starboard Bow Longitudinal Stiffener Check
Figure 57 Stbd Bow Proposed Support Structure
The proposed bow foundation support structure can be seen in Figure 57. The double bitt and chock transverse headers are both attached to the same longitudinal stiffener. With both reactionary forces being applied, the typical L 4x3x1/4” stiffener failed the section modulus and shear stress check. Upon further analysis, a 15x5x3/8” flange plate was determined to provide enough strength to support both headers.
The calculations used to determine the size of the proposed longitudinal header can be found on the following pages.
Conrad Shipyard, LLC. | Page 33 of 48
Figure 58 BeamPro Loading Diagram
Figure 59 BeamPro Shear Diagram
Figure 60 BeamPro Bending Moment Diagram
Figure 61 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 60 is 40.22 in³. The proposed header has 48.85 in³ available. The required shear area based on the maximum shear force in Figure 59 is 3.79 in². The header has 5.77 in² available. The sections properties and stress results can be found in Figure 62.
Conrad Shipyard, LLC. | Page 34 of 48
Figure 62 Section Properties and Stress Results
0.375 in ABS Grade A Flange Plate ABS Grade A FP 15x5x3/8"
66.00 in
24.00 in
8.25 in (L/8)
FP 15x5x3/8"
14.63 in
0.38 in
5.00 in
0.38 in
15.38 in
535.049 in4
121.024 in3
48.845 in3
16.359 in2
5.766 in2
5.72 in 11.54
820,527 lb-in 820.53 kip-in 51,471 lbs 51.47 kips
34 ksi
20.4 ksi
40.222 in3
PASS
34 ksi
13.6 ksi
3.785 in2
PASS
Spacing of Beam
Stbd Bow Long Stiffener Check
Plate Thickness Structure Type
Flange Plate Size Length of Beam
Area of Section =
Effective Width
Size Web Depth: DW
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange =
Fy =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Maximum Moment = Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress
Allowable Shear Stress =
Conrad Shipyard, LLC. | Page 35 of 48
7.2. Port Bow Longitudinal Stiffener Check
Figure 63 Port Bow Proposed Support Structure
The proposed bow foundation support structure can be seen in Figure 63. With the reactionary force of the chock being applied, the typical L 4x3x1/4” stiffener failed the section modulus and shear stress check. Upon further analysis, a 10x4x3/8” flange plate was determined to provide enough strength to support the transverse header.
following pages
Figure 64 BeamPro Loading Diagram
Figure 65 BeamPro Shear Diagram
Conrad Shipyard, LLC. | Page 36 of 48
Figure 66 BeamPro Bending Moment Diagram
Figure 67 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 66 is 10.98 in³. The proposed header has 24.32 in³ available. The required shear area based on the maximum shear force in Figure 65 is 2.21 in². The header has 3.89 in² available. The sections properties and stress results can be found in Figure 68.
Conrad Shipyard, LLC. | Page 37 of 48
Figure 68 Section Properties and Stress Results
Flange Plate ABS Grade A FP 10x4x3/8"
66.00 in
24.00 in
8.25 in (L/8)
FP 10x4x3/8"
9.63 in
0.38 in
4.00 in
0.38 in
10.38 in
190.820 in4
75.432 in3
24.323 in3
14.109 in2
3.891 in2
3.68 in 17.95
224,048 lb-in 224.05 kip-in 30,114 lbs 30.11 kips
34 ksi
20.4 ksi
10.983 in3
PASS
34 ksi
13.6 ksi
2.214 in2
PASS
Spacing of Beam
Port Bow Long Stiffener Check
Plate Thickness Structure Type
Flange Plate Size Length of Beam
Area of Section =
Effective Width
Size Web Depth: DW
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange =
Fy =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Maximum Moment = Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress
Allowable Shear Stress =
Conrad Shipyard, LLC. | Page 38 of 48
7.3. Stbd Stern Longitudinal Stiffener Check
Figure 69 Stbd Stern Proposed Support Structure
The proposed stern foundation support structure can be seen in Figure 69. The double bitt and chock transverse headers are both attached to the same longitudinal stiffener. With both reactionary forces being applied, the typical L 4x3x1/4” stiffener failed the section modulus and shear stress check. Upon further analysis, a 15x5x3/8” flange plate was determined to provide enough strength to support both headers.
following pages.
Conrad Shipyard, LLC. | Page 39 of 48
Figure 70 BeamPro Loading Diagram
Figure 71 BeamPro Shear Diagram
Figure 72 BeamPro Bending Moment Diagram
Figure 73 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 72 is 39.58 in³. The proposed header has 48.85 in³ available. The required shear area based on the maximum shear force in Figure 71 is 4.14 in². The header has 5.77 in² available. The sections properties and stress results can be found in Figure 74.
Conrad Shipyard, LLC. | Page 40 of 48
Figure 74 Section Properties and Stress Results
Flange Plate ABS Grade A FP 15x5x3/8"
64.00 in
24.00 in
8.00 in (L/8)
FP 15x5x3/8"
14.63 in
0.38 in
5.00 in
0.38 in
15.38 in
535.049 in4
121.024 in3
48.845 in3
16.359 in2
5.766 in2
5.72 in 11.19
807,359 lb-in 807.36 kip-in 56,365 lbs 56.37 kips
34 ksi
20.4 ksi
39.576 in3
PASS
34 ksi
13.6 ksi
4.144 in2
PASS
Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress Fy =
Allowable Shear Stress = Required Shear Area =
Shear Area Check
Maximum Moment =
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange = Area of Section =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Stbd Stern Long Stiffener Check
Plate Thickness Structure Type
Flange Plate Size Length of Beam Spacing of Beam Effective Width
Size Web Depth: DW
Conrad Shipyard, LLC. | Page 41 of 48
7.4. Port Stern Longitudinal Stiffener Check
Figure 75 Port Stern Proposed Support Structure
The proposed bow foundation support structure can be seen in Figure 75. With the reactionary force of the chock being applied, the typical L 4x3x1/4” stiffener failed the section modulus and shear stress check. Upon further analysis, a 10x4x3/8” flange plate was determined to provide enough strength to support the transverse header.
following pages
Figure 76 BeamPro Loading Diagram
Figure 77 BeamPro Shear Diagram
Conrad Shipyard, LLC. | Page 42 of 48
Figure 78 BeamPro Bending Moment Diagram
Figure 79 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 78 is 17.78 in³. The proposed header has 24.323 in³ available. The required shear area based on the maximum shear force in Figure 79 is 1.97 in². The header has 3.89 in² available. The sections properties and stress results can be found in Figure 80.
Conrad Shipyard, LLC. | Page 43 of 48
Figure 80 Section Properties and Stress Results
Flange Plate ABS Grade A FP 10x4x3/8
64.00 in
24.00 in
8.00 in (L/8)
FP 10x4x3/8
9.63 in
0.38 in
4.00 in
0.38 in
10.38 in
190.820 in4
75.432 in3
24.323 in3
14.109 in2
3.891 in2
3.68 in 17.40
362,655 lb-in 362.66 kip-in 26,744 lbs 26.74 kips
34 ksi
20.4 ksi
17.777 in3
PASS
34 ksi
13.6 ksi
1.967 in2
PASS
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress Fy =
Allowable Shear Stress = Required Shear Area =
Shear Area Check
Maximum Moment = Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
SM Plate = SM Flange =
Area of Section = Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I =
Flange Plate Size Length of Beam Spacing of Beam Effective Width
Size Web Depth: DW
Port Stern Long Stiffener Check
Plate Thickness Structure Type
Conrad Shipyard, LLC. | Page 44 of 48
8 Towing Padeye Foundation Calculations
Figure 81 Typical Towing Padeye
The bow towing padeyes, as shown in Figure 81, have a safe working load of 121.25 kips. The pull height of the chock is 7 inches above the deck. The base is 30 inches long and 14.25 inches wide. The load was determined to be in the longitudinal direction, and the overturning moment calculation can be found in Figure 82.
Figure 82 Overturning Moment Calculation
Three towing padeyes can be found on deck, one located on the centerline bulkhead, and the other two located on longitudinal stiffeners 12 ft port and starboard off centerline. The bulkhead was assumed to
Safe Working Load = 121,253 lbs
7.000 in
848,771 lb-in
848,771 lb-in
30.000 in
28,292 lbs
28,292 lbsForce Per Beam (1 Beams) =
Width of Base =
Force Couple = Number of Beams =
Calculate the Force due to Max Overturning Moment:
F = Max Overturning Moment / Distance Between Feet Force Couple =
Calculate the Max Overturning Moment of the Padeye:
Height of Padeye from Deck =
Maximum Overturning Moment =
MOORING AND TOWING FOUNDATION CALCULATIONS
Conrad Shipyard, LLC. | Page 45 of 48 have enough strength to support the longitudinal load. However, the port and starboard locations were analyzed to ensure there is adequate strength to support the padeyes.
The proposed foundation structure for the port and starboard padeyes consists of replacing the typical L 4x3x1/4” stiffeners with FP 14x4x3/8” headers. An 1” insert plate is also included to increase foundation strength.
Figure 83 Port Towing Padeye and Suggested Structure, Stbd Side Similar
The calculations used to determine the foundation can be found on the following pages.
Figure 84 BeamPro Loading Diagram
Figure 85 BeamPro Shear Diagram
Conrad Shipyard, LLC. | Page 46 of 48
Figure 86 BeamPro Bending Moment Diagram
Figure 87 BeamPro Deflection Diagram
The required SM based on the maximum bending moment in Figure 86 is 18.2 in³. The proposed header has 45.24 in³ available. The required shear area based on the maximum shear force in Figure 85 is 1.14 in². The header has 5.77 in² available. The sections properties and stress results can be found in Figure 88.
Conrad Shipyard, LLC. | Page 47 of 48
Figure 88 Section Properties and Stress Results
1.375 in ABS Grade A Flange Plate ABS Grade A FP 14x4x3/8"
66.00 in
24.00 in
8.25 in (L/8)
FP 14x4x3/8"
13.63 in
0.38 in
4.00 in
0.38 in
15.38 in
595.936 in4
270.380 in3
45.246 in3
39.609 in2
5.766 in2
3.88 in 17.02
371,911 lb-in 371.91 kip-in 15,432 lbs 15.43 kips
34 ksi
20.4 ksi
18.231 in3
PASS
34 ksi
13.6 ksi
1.135 in2
PASS
Towing Padeye Headers
Plate Thickness Structure Type
Flange Plate Size Length of Beam Spacing of Beam Effective Width
Size Web Depth: DW
Maximum Moment =
Web Thick: TW
Flange Width: Bf
Flange Thick: Tf
Total Depth: Dt
Inertia I = SM Plate =
SM Flange = Area of Section =
Shear Area As = Rad of Gyra. R =
SLNDR Ratio L/r =
Max Shear Force =
Required SM = Max Moment / Allowable Bending Stress Fy =
Allowable Bending Stress = Required Section Modulus =
Section Modulus Check
Required Shear A = Max Shear F / Allowable Shear Stress Fy =
Allowable Shear Stress =
File details come from the government source that posted it. Updated .