Results from full-scale measurements of midship bending stresses on three dry cargo ships

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ARCHIEF

SSC-2 09

T:

iotheek vaZ7Z

Teckrsche Hogeschoo,

Deift

DOCUMENTATIE

_(:

-DATUM:

RESULTS FROM FULL-SCALE MEASUREMENTS

OF MIDSHIP BENDING

_{STRESSES ON THREE}

DRY CARGO SHIPS

This document has been approved

for public release and sale;

its

distribution is unlimited.

SHIP STRUCTURE COMMITTEE

1970

Technische Hogeschao!

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Dear Sir:

A project initiated in early 1959 and reported through

earlier

SSC reports has been nearly

completed.

The objective was to obtain

records for statistical analysis

of the longitudinal bending moment

strains experienced by various

types of ships, operating on

different trade routes.

Herewith is a report that covers

the most recent three and

one-half yearts compilation of data.

Sincerely,

1970

I'2

W. F. REA, III

Rear Admiral, U.S. Coast

Guard

Chairman, Ship Structure Committee

MEMBER AGENCIES: ADDRESS CORRESPONDENCE TO:

UNITED STATES COAST GUARD SECRETARY

NAVAL SHIP SYSTEMS COMMAND SHIP STRUCTURE COMMITTEE

MILITARY SEA TRANSPORTATION SERVICE U.S. COAST GUARD HEADQUARTERS

MARITIME ADMINISTRATION WASHINGTON, D.C. 2059t

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Technical Report

on

Project SR-153, 'Ship Response Statistics"

to the

Ship Structure Committee

RESULTS FROM FULL-SCALE MEASUREMENTS _OF MIDSHIP BENDING STRESSES ON THREE DRY

CARGO SHIPS

by

I. J. Walters and F. C. Bailey

under

Department of the Navy NAVSEC Contracts: NObs 94252

N00024-67-C-5312 N00024-68-C-5231

This document hs been approved for public release and

sales its distribution is unlimited.

U, S, Coast Guard Headquarters Washington, D. C.

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This report summarizes the activities undertaken by

Teledyne

Materials Research under Ship Structure

Committee

Project SR-153

during a three and one-half year

period to

investigate certain aspects of the structural response of

three dry-cargo ships to wave loads. This work continues

earlier studies sponsored by the Ship Structure Committee.

Work is concluding on MORMACSCAN and CALIFORNIA BEAR and

will continue on WOLVERINE STATE

which is also instrumented

to gather data for project SR-l72, "Slamming Studies" to be

reported under separate cover.

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PAGE INTRODUCTION i PRESENTATION OF DATA 2 DISCUSSION OF DATA 5 SUMMARY 8 ACKNOWLEDGEMENTS 9 REFERENCES 9 LIST OF FIGURES 11

APPENDIX A-1. - CALIBRATION OF THE

_{CALIFORNIA BEAR}

45

APPENDIX A-2. _{- CALIBRATION OF THE} _MORJvJACSCAN

52

APPENDIX B - A GUIDE TO TABULATED DATA

62

APPENDIX C - _{WOLVERINE STATE} _GAGES

70

CURVE CORRECTION FACTORS

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program to improve the hull structures of ships by an extension of knowledge pertaining to design, materials and methods of fabrication.

RADM, W. F. Rea, III, USCG, Chairman Chief, Office of Merchant Marine Safety

U. S. Coast Guard Headquarters

Capt. W. R. Riblett, USN

Head, Ship Engineering Division Naval Ship Engineering Center

Capt. T. J. Banvard, USN

Maintenance and Repair Officer Military Sealift Command

SHIP STRUCTURE SUBCOMMITTEE

The SHIP STRUCTURE SUBCOMMITTEE acts for the Ship Structure Committee on technical matters by providing technical coordination for the determination of goals and objectives of the program, and by evaluating and interpreting the

results in terms of ship structural design, construction and operation.

NAVAL SHIP ENGINEERING CENTER U. S. COAST GUARD

Mr. J. B. O'Brien - Acting Chairman LCDR C. S. Loosmore, USCG - Secretary Mr. J. B. O'Brien - Contract Administrator CDR C. R. Thompson, USCG - Member Mr. G. Sorkin - Member LCDR J. W. Kime, USCG - Alternate

Mr. H. S. Sayre - Alternate Capt. L. A. Colucciello, USCG - Alternate Mr. I. Fioriti - Alternate

NATIONAL ACADEMY OF SCIENCES MARITIME ADMINISTRATION

Mr. F. Dashnaw - Member Mr. A. Maillar - Member Mr. R. Falls - Alternate

Mr. W. G. Frederick - Alternate AMERICAN BUREAU OF SHIPPING

Mr. S. G. Stiansen - Member Mr. F. J. Crurn - Member

OFFICE OF NAVAL RESEARCH

Mr. J. M. Crowley - Member Dr. W. G. Rauch - Alternate

NAVAL SHIP RESEARCH & DEVELOPMENT CENTER

Mr. A. B. Stavovy - Alternate

MILITARY SEALIFT COMMAND

Mr. R. R. Askren - Member

Lt. J. G. T. E. Koster, USN - Member

Mr. E. S. Dillon Deputy Chief

Office of Ship Construction Maritime Administration

Mr. C. J. L. Schoefer, Vice President American Bureau of Shipping

Mr. A. R. Lytle, Liaison Mr. R. W. Rumke, Liaison

Prof. R. A. Yagle, Liaison

SOCIETY 0F NAVAL ARCHITECTS & MARINE ENGINEERS

Mr. T. M. Buermann, Liaison

AMERICAN IRON AND STEEL INSTITUTE

Mr. J. R. LeCron, Liaison

BRITISH NAVY STAFF

Dr. V. Flint, Liaison

WELDING RESEARCH COUNCIL

Mr. K. H. Koopman, Liaison Mr. C. Larson, Liaison

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These investigations are providing statistical data from which maximum ex-pected values of vertical longitudinal bending moment may be predicted.

Ulti-mately, through correlation with model tests at the Davidson Laboratory of Stevens Institute of Technology, and analysis by Webb _{Institute of Naval Architecture,} these data will contribute to the design of more efficient ships.

Data acquired by the investigators through _{April 1965 covering about 18,500} hours at sea were analyzed and presented in graphical form in Ship Structure Com-mittee Reports SSC-164 and SSC-181 (References 1 and 2). The design and instal-lation of the stress-measuring and recording system, and preliminary presentation of some data have been reported in Ship _{Structure Committee Reports SSC-l5O, 153,} and 159 (References 3, 4, and 5).

This present report includes data from thirteen voyages of the CALIFORNIA BEAR, twelve voyages of MORMACSCAN, and nineteen voyages of WOLVERINE STATE. _{These data represent a total of 16,000}

hours at sea for the three ships during the period May 1965 _{to November 1968.}

Table I is a chronol-ogical record of ship visits necessary to acquire these data and maintain the

equipment. Table II lists the specifications of the _{three ships.} _{The results of}

the calibration of CALIFORNIA BEAR _{are reported in Appendix A-1 and the results} of the calibration of MORMACSCAN are reported in Appendix A-2.

The data in this report were obtained under contracts NObs-94252, N00024-67-C-5312, and N00024-68-C-523l.

PRESENTATION OF DATA

The data shown as dot-plots were acquired by the following procedures, _which are similar for stress and wave height data.

The shipboard magnetic tape system records the signals generated by _the stress transducers for at least one-half hour _{Out of every four hours at sea.}

At

the beginning of each four-hour interval a calibration signal (obtaining _by shunt-ing one arm of the bridge with _{a known resistance) is superimposed.}

When the tape is played back in the investigators'

laboratory, the Sierra Probability Analyzer is triggered by each calibration signal _{and provides a histogram and statistical}

data representing the first twenty minutes of _{each record interval (see Figure}

15,

SSC-l69, Reference 1). _{At the playback speed of 60 inches per second, a half hour} of ship data requires 9 seconds _{to be analyzed by the machine.}

The officer on watch maintains _{a logbook.}

Every four hours an entry is made and given a sequential index number. _{At the time of the logbook entry the}

elapsed time meter reading is noted, from which the index number may be matched

to _{the appropriate interval calibration}

signal. Report SSC-153 (Reference 4)

contains reproductions of typical _{logbook pages.}

The oscillographic output from the probability analyzer is transcribed manually in terms of a scale of counts from the digital registers. _{Only the bars} representing the greatest peak-to-trough

stress, the total number of stress

variations analyzed, and the mean square value of the data sample _{are transcribed.} Two punched cards are prepared _{for each data interval.}

The first con-tains all the logbook data and

the second contains the above quantities from the probability analyzer.

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Table I

Ship Visits to Maintain Equipment

Date

Instrumented Voyage Number

Ship

Voyage Number

Equipment Operation - Remarks

NS MMS CB NS MMS CB Abbreviations: NS = SS WOLVERINE STATE

MMS = SS MORMACS CAN CB = SS CALIFORNIA BEAR

5/12/65

37

243

Stbd Amplifier Failed, M-G problems, no data

6/4/65

7

27

Fuse Blew, 43 good intervals

6/16/65

38

245

Fuse Blew in record electronics, M-G problems,

32 good intervals

7/28/65

39

247

OK, 204 good intervals, calibration made

8/31/65 8 28 0K, 121 good intervals 9/1/65 40 249

M-G problems and recorder power supply problems,

removed power supply, 102 good intervals

11/4/65 9 29 0K, 72 good intervals 12/16/65 lO 30 0K, 88 good intervals 3/7/66 11 31 0K, 72 good intervals 3/9/66 41 259

OK, 48 good intervals, expanded system on

3/22/66 1 25 0K, 79 good intervals 4/25/66 42 261 0K, 90 good intervals 4/27/66 12 32 0K, 120 good intervals 6/13/66 13 33

Rewind problem, one pass only, 65 good intervals

6/16/66 43 263 0K, 119 good intervals 6/16/66 2 26 0K, 98 good intervals 7/25/66 44 265

First roll NG, 2nd roll 0K, 36 good intervals

7/30/66 14 34 0K, 131 good intervals 9/3/66 45 267 0K, 55 good intervals 9/19/66 3 27

Noise in data, several of 100 intervals unusble

10/7/66

46

269

Port amplifier failed, no data:

59 good intervals

from starboard gage

10/11/66

15

35

One pass only, recorder trouble;

28 good intervals 11/2/66 47 271 0K, 88 good intervals 11/28/66 16 36

One pass only, recorder trouble; 66 good intervals

12/12/66

4

28

Zero timer failure, 22 good intervals

12/20/66 48 273 0K, 93 good intervals 1/12/67 17 37 0K, 118 good intervals 2/16/67 5 29 0K, 115 good intervals 2/20/67 49 275

No data, new crew

3/2/67

18

38

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Table I

Ship Visits to Maintain Equipment

(cont.)

*SS MORMACSCAN

- minimum maintenance of equìpment until

calibrated and removal of equipment.

Date

Instrumented _{Voyage Number}

Ship Voyage Number Equipment Operation - Remarks WS MMS CB WS MMS CB 4/3/67 50 277

Starboard amplifier failed after 47

good intervals;

Port data 104 good intervals

5/1/67

19

39

Recorder bearing failed, 42 good

intervals* 5/10/67 6 30 0K, 154 good intervals 6/20/67 * 40

No data, recorder inoperative

6/21/67

51

279

Both amplifiers failed midway in

voyage, compensation

channel drifting because of faulty good intervals

7/26/67 7 31 0K, 98 good intervals 8/30/67 * 41 No data taken* 9/25/67 52 280

Port amplifier failed in

voyage, compensation channel

drifts, badly because of faulty

VCO about 130 good

intervals from port gage, 200 good stbd gage

10/6/67

8

32

Slight tape slippage at end of reels,

11/9/67 * 42 No data taken* 12/18/67 9 33 0K, 105 good intervals 12/22/67 53 281 0K, 223 good intervals 2/1/68 * 43

Amplifier failed, 19 good intervals*

2/12/68 54 282 0K, 118 good intervals 3/8/68 10 34 0K, 128 good intervals 5/22/68 11 35 0K, 102 good intervals 6/20/68 56 284 0K, 149 good intervals 8/5/68 12 36

0K, 124 good intervals, calibration

made

9/18/68

57

285

Port amplifier failed mid-voyage,

258 intervals

starboard gage, 144 intervals

port gage 9/30/68 46 Calibration made 10/25/68 13 37 Equipment removed 11/13/68 58 286

Starter control relay failed mid-voyage,

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Tab'e II

Ship Specifications

WOLVERINE STATE MO RNAC S CAN CALIFORNIA BEAR Type: C-4-S-B5 Machinery-Aft 1624 Machinery

C4-S-1A Standard Mariner

Dry Cargo Vessel

Amidships Dry Cargo Vessel

Dry Cargo Vessel

Builder:

Sun Shipbuilding and

S ame

Bethlehem Pacific Coast Steel

Drydock Company Chester, Pennsylvania

Co.

Shipbuilding Div. San

Francisco, California Date: September 1945 October 1960 February 1954 Hull Number: 359 622 5463 Length Overall: 520' - O" 483' - 3" 563' - 7-3/4" Length Btwn Perp.: 496' - O" 458' - O" 528' - 6" Beam, Molded: 71' - 6" 68' - 0" 76' - O" Depth, Molded: 54' - O" 41' - 6" 44' - 6"

Load Draft, Molded, Design

30' - 0"

28' - 6"

27' - O"

Load Draft, Keel

32' - 9-7/8" 31' - 5" 29' - 10-1/16" Gross Tonnage: 10,747 L.T. 9,315 L.T. 9,216 L.T. Net Tonnage: 6,657 L.T. 5,609 L.T. 5,366 L.T.

Midship Section Modulus

45,631

in2 ft (to top

30,464 in2 (to top

43,900

in2 ft (to

of upper deck)

upper deck)

Light Ship Weight:

6,746 L.T.

5,882 L.T.

7,675 L.T.

Dead Weight at Load Draft:

15,348 L.T.

12,483 L.T.

13,418 L.T.

Propeller, Normal

Oper-ating

RPM:

80

93

85

Shaft Horsepower, Normal

9,000

11,000

17,500

Shaft Horsepower, Maximum

9,900

12,100

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The computer calculates relative wave direction and transforms the probability

ana-lyzer output into maximum peak-to-trough stress in kpsi, mean square stress in kpsi2, and root-mean-square stress in kpsi.

The computer output for each voyage consists of a tabulation by interval number and also, optionally, _{a set of output punched cards.}

The data from one pass of the magnetic tape aboard ship have been _{given a double-letter code for}

iden-tification. _{This coding appears on the printout and on each output card.}

A com-pilation of the code letters for the data of this report and sample printouts _are shown in Appendix B.

III. _{DISCUSSION OF DATA}

A. General

When considering the absolute values of the stress data, it must be kept in mind that these data are presented as peak-to-trough stress variations, _{and not} as single positive or negative amplitudes about an average level. Absolute average values are difficult to determine and _{are variable with loading and thermal}

condi-tions. _{Statistical procedures for analyzing peak-to-trough values of random}

vari-ables, moreover, are well established.

The collection of statistical ship stress data can be of real signifi-cance to the ship designer and/or classification _authority.

When interpreted in terms of applied wave bending moment, such data can be used to determine a suitable design value of bending moment by _{two approaches, as dealt with in detail under} Project SR-171.

A mathematical or probability model _{can be devised that will permit} a long-term bending moment probability distribution

to be extrapolated from two to five years of data, to the lifetime of a ship or of several similar _ships. _This leads to a means of predicting the highest expected bending _{moment in 20 years or} 200 ship-years for one class of vessel.

Statistical data provides the basis for checking a prediction of long-term distribution made from model test results and ocean wave data. _{If good results} are obtained in several cases, then the _{prediction technique can be applied}

with confidence to new and unusual design.

Each data point is based on a twenty-minute portion of a thirty-minute sample record (interval), and is _{assumed to be representative of four hours of} oper-ation of the ship in the _seaway.

In heavy weather situations where the tape re-corder operates longer than one-half hour out of every four, only the _{twenty-minute} portion following the calibration _{signal (every four hours) is analyzed,}

under

cur-rent procedures.

Coastwise and in-port data have been eliminated.

There is considerable scatter of the data points in the dot-plots. _This scatter might be explained on the basis of the statistical _{nature of the data, since} the ship operates at various

headings relative to the sea, and at various speeds within a given sea state. _{Because the reported}

sea-state information is based on

visual observations, _{some spread in these values}

as a result of individual inter-pretation is also likely.

Based on Appendices A and C, the MORMACSCAN data are probably accurate as reported; a small correction is optional on the CALIFORNIA BEAR data; and

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CALIFORNIA BEAR

Figures 1 and 2 present uncorrected RMS stress and uncorrected maxi-mum peak-to-trough stress plotted versus Beaufort Sea State for 13 voyages, all between the West Coast of the United States and the Orient. This represents a

total of 1250 intervals taken from January 1966 when the system was first put into operation up to October 1968. The maximum peak-to trough stress recorded was

12,300 psi at a sea state of 8.

A satisfactory bending calibration was made on this ship in early August 1968 and is reported in Appendix A-1. Based on this calibration and other

available information, the CALIFORNIA BEAR data should be corrected by a factor

of 1.08. The recording instruments have been removed from this ship.

MORMACSCAN

The data collected from MORMACSCAN for the reporting period are pre-sented in Figures 3 through 6, inclusive. They are divided into two groups, voy-ages to Europe (247 intervals) and voyages to South America (824 intervals). The

average values of these plots are compared in Figures 33 and 34 along with previous data reported for this vessel in SSC 181. It appears that the stresses produced,

sea state for sea state, vary between the European and the South American trade

routes. Above sea state 3, the South

American

voyages produce RMS stresses 500

psi lower than the European voyages. Likewise, the maximum peak-to-trough stresses are about 1,000 psi lower. The curve labeled "mean" is the overall average for about 1,600 intervals, one quarter of them produced in North Atlantic crossings and three quarters of them on the trade route between the eastern seaboards of North and South America.

An adequate bending calibration was made on this ship in early October 1968 and is reported in Appendix A-2. No correction of the reported data is

recom-mended.

No further data are being taken from this ship and the equipment will be removed at the next opportunity.

WOLVERINE STATE

Stress data from the WOLVERINE STATE are divided into three categories:

North Atlantic, Summer Season North Atlantic, Winter Season

Pacific

The seasonal division was found necessary in the North Atlantic because of the greater likelihood of encountering large swells at relatively low Beaufort Sea States in the winter. This seasonal variation is not as severe in the Pacific and therefore these data are presented as a mixture of both summer and winter.

This ship is unique in that the stress gages mounted on the port and starboard sides are not combined into a single bridge, but are connected to form two separate bridges. This allows us to determine the effect of unfairness upon individual gages (see Appendix C). In order to get vertical bending stress the tapes are played back in the laboratory and the port and starboard channels are electrically combined. The individual channel sensitivities are adjusted such

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Data obtained from a single transducer is to be con-sidered raw data in that the unfairness correction has not been applied. All these curves are labeled with the appropriate correction _factor.

In addition, data obtained from only one side contains a component of horizontal bending stress which cancels out in the combined data. _{In order to} determine the statistical effect of horizontal _{bending, dot-plots have been made} showing the same data for combined,

port uncombined (uncorrected), and starboard un-combined (uncorrected). _{The uncorrected averages are then corrected for unfairness} and compared with the combined _averages.

The resulting correction for horizontal bending may then be applied to data which _{otherwise would be unusable because good} data was collected from only one side.

North Atlantic Summer Data

These data were gathered from Voyages 245, 247, 249, 261, 263, 265,

and 267. _{Figures 7 and 8 show data taken from the first six of these voyages}

as the

electrical sum of the Port and Starboard Transducers. The discriminator gains on the tape playback unit were adjusted to compensate for the unfairness corrections _for each gage (see Appendix C), and, _{of course, horizontal bending}

is eliminated by hav-ing gages on both sides of the ship.

Therefore, the stresses in Figures 7 and 8 are

the actual stresses in the ship and _{require no further corrections.}

Figures 9 and 10 show the _{same data as seen by Port Transducer} (un-corrected) and Figures 11 and 12 _{show the same data as}

seen by the Starboard

Trans-ducer (uncorrected). _{The data plotted in these figures}

should be identical to Fig-ures 7 and 8 after applying a correction for

unfairness and for horizontal _bending. Since the effect of horizontal bending

is unknown, the averages from Figures 7-12 were plotted in Figures 35 and 36, unfairness _{corrections made, and the effect of} horizontal bending determined.

A fairly good match was made by reducing the cor-rected uncombined stresses by 12% for each sea state. _{The horizontal bending}

was

also found to be 12% for the Winter and Pacific Data.

Figures 13 and 14 represent uncorrected data taken on Voyage 267 where both channels were recording transducers from the starboard side. In order to make

these data usable, the unfairness

correction was applied and 12% was deducted from the result to correct for horizontal bending. _{This was then averaged with the}

aver-ages from Figures 7 and 8 to produce the

Atlantic Summer portion of Figures 41 and 42. North Atlantic Winter Data

These data were gathered from _{Voyages 259, 271, 273, 277 and}

282. On only one of these voyages (259) were data produced from _{both sides simultaneously.} This is represented in Figures _{15 and 16 as combined data}

to which no further correc-tions are required and in Figures 17-20 as individual _{uncorrected port or starboard}

data. _{The averages of these figures}

are compared in Figures 37 and 38. _{The effect} of horizontal bending on these data is the same 12% _{as found in the summer data.}

Figures 21 and 22 list the

uncorrected data obtained from the Port Transducer during Voyages 271, 273, _{and 282.}

Figures 23 and 24 list the uncor-rected data obtained from the _{New Starboard Transducer during Voyage 277.}

In

order to make use of these _{data they have been corrected}

for unfairness, corrected for horizontal bending,

averaged with the data of Figures 15 and 16 and plotted _as the Atlantic Winter portion of Figures 41 and 42.

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These data were collected from Voyages 279, 280, 281, 283, 284, 285

and 286. Data were obtained from both sides during Voyages 279, 280, 281, 285 and

286 and are presented as port and starboard electrically combined data in Figures

25 and 26. As with the Atlantic data, these data require no further corrections.

The data from the individual Port and Starboard Transducers (uncorrected) for these voyages are presented in Figures 27-30. A comparison is made of the electrically combined and the individual transducers in Figures 39 and 40. As before, the cor-rection for horizontal bending is determined to be -12%.

During Voyages 283 and 284 data were taken only from the Port

Trans-ducer. The uncorrected results of these voyages are plotted in Figures 31 and 32.

In order to utilize these data the averages of Figures 31 and 32 are corrected for unfairness and horizontal bending and averaged with the data of Figures 25 and 26. These data are presented as the Pacific portion of Figures 41 and 42.

WOLVERINE STATE WAVE DATA

A Tucker Wave Meter was installed aboard WOLVERINE STATE in April, 1966 and connected such that its electrical output was fed to one channel of the slow-speed magnetic tape recorder in lieu of the paper chart readout furnished with the

machine. With the exception of two interruptions due to electrical faults in the

Tucker, this device has been producing data since installation. Figures 45 through 62, taken from data from Voyages 279, 283 and 284 are used here to illustrate the nature of these data.

Figures 45, 51, and 57 are plots of BJS Stress vs. RMS Wave Height.

Fig-ures 46, 52 and 58 are plots of Maximum Peak-to-Trough Stress vs. Maximum Peak-to-Trough Wave Height. Each tape pass and hence, each section of the voyage has been plotted with different symbols. In some cases good correlation is indicated by a fairly well defined band of increasing stress with increasing wave height for a particular leg of a voyage. In other cases the data are scattered and much poorer correlation is exhibited. It should be emphasized here that there is no "observer" effect in this presentation. Both stress and wave height are primary

transducer-generated quantities.

Figures 49, 55 and 61 are dot-plots of Estimated Wave Height (from the data logbooks) vs. Beaufort Sea State. Figures 48, 54 and 60 are dot-plots of

Max-imum Peak-to-Trough Wave Height vs. Beaufort Sea State. Figures 47, 53 and 59 are dot-plots of RMS Wave Height vs. Beaufort Sea State. Figures 50, 56 and 62 replot the averages from the dot-plots for each of the three voyages and include stress plots for comparison. The Tucker Wave Meter utputs do not follow either the Esti-mated Wave Heights or the stresses.

OVERALL AVERAGES

The overall averages, regardless of trade route or season, of all three ships are plotted in Figures 43 and 44.

IV. SUMMARY

CAlIFORNIA BEAR data collection has ceased after 13 instrumented voyages. A calibration of the bending transducers indicates a correction factor of 1.08 should be applied to the data. The data listed in Figures 1 and 2 are raw data and should be multiplied by this factor to get actual bending stress. The CALIFORNIA BEAR aver-ages in Figures 43 and 44 have already been corrected.

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MORNACSCAN data collection has ceased after 19 instrumented voyages. A calibra-tion of the bending transducers indicates that no correccalibra-tion factor is necessary. Figures 33 and 34 sum up the data taken for the period of this report and compare it with that reported in SSC181.

WOLVERINE STATE data collection continues. _{Further investigation of the} correc-tions required because of side shell unfairness have increased confidence in their

use. _{This investigation is reported in Appendix C.}

The effect of horizontal bending _{on the WOLVERINE STATE data has been}

investi-gated. _{A reduction of 12% applied to the corrected average from a single transducer}

will statistically remove the effect of horizontal bending. Electrical summing of the port and starboard transducers will eliminate horizontal bending on a point-to-point basis if the indivídual channel gains are adjusted to compensate for the

un-fairness corrections. _{Figures 41 and 42 sum up all the WOLVERINE STATE data taken} for the period of this report. _{No corrections to these data are necessary.}

From the Tucker Wave Meter plots, which are representative of all the wave data collected, very little can be firmly concluded. _{Although the meter does not agree} with the estimated wave heights, the accuracy of the estimates is probably very poor having been made by several different persons whose ability to judge wave heights correctly is unknown. _{The relationship between measured wave height and bending} stress is also poor, but since the stress is directly proportional to both wave height and wave length, a large scatter would be expected in a sample containing a

ACKNOWLEDGEMENTS

This project is sponsored by the Ship Structure Committee with guidance _from the Ship Hull Research Committee of the National Academy of Sciences, National Research Council.

The cooperation of States Marine Lines has continued to contribute to the prog-ress of this investigation. _{Mr. John Ritter and the officers and men of SS}

WOLVERINE STATE should be recognized for their efforts in this project.

The wholehearted cooperation of Pacific Far East Lines and in particular Mr. V. J. Bahorich and the officers and men of SS CALIFORNIA BEAR deserve special vote of

thanks.

Moore-McCormack Lines, Mr. F. A. Heess and the officers and men of SS MORNACSCAN also deserve acknowledgement for their continued contribution.

REFERENCES

Fritch, D. J., Bailey, F. C., and Wise, N. S., Results from Full-Scale Measurements of Midship Bending Stresses on Two C4-S-B5 Dry-Cargo Ships

Operating in North Atlantic Service, Ship Structure Committee Report SSC-l64, September 1964.

Fritch, D. J., Bailey, F. C., and Wheaton, J. W., Results from Full-Scale Measurements of Midship Bending Stresses on Two Dry-Cargo Ships - Report

#2, Ship Structure Committee Report SSC-l81, March 1967.

Fritch, D. J.., and Bailey, F. C., An Unmanned System for Recording Stresses and Acceleration on Ships at Sea, Ship Structure Committee Report SSC-15O,

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Bending Moment Data from Ships at Sea, Ship Structure Committee Report SSC-153, December 1963.

Bailey, F. C., Fritch, D. J., and Wise, N. S. , Acquisition and

Analy-sis of Acceleration Data, Ship Structure Committee Report SSC-159, February 1964.

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Figure 1 2 3 4 5 6 7

10 _{WOLVERINE STATE Atlantic Summer}

Trough

11 _{WOLVERINE STATE Atlantic Summer} 12 _{WOLVERINE STATE Atlantic Summer}

Peak-to-Trough

, q

13 _{WOLVERINE STATE Atlantic Summer} 14 _{WOLVERINE STATE Atlantic Summer}

Trough, Voyage 267

15 _{WOLVERINE STATE Atlantic Winter} 16 _{WOLVERINE STATE Atlantic Winter}

Trough, Voyage 259.

17 _{WOLVERINE STATE Atlantic Winter} 18 _{WOLVERINE STATE Atlantic Winter}

Trough, Voyage 259

19 _{WOLVERINE STATE Atlantic Winter}

20 _{WOLVERINE STATE Atlantic Winter}

Peak-to-Trough, Voyage 259 WOLVERINE STATE Atlantic Winter

21 22 23 24 Trough, Voyage 277 LIST 0F FIGURES

Dot-Plots of Stress vs. Beaufort Sea State

Page

CALIFORNIA BEAR EMS

. ₁₄

CALIFORNIA BEAR Max. Peak-to-Trough

14

MORMACSCAN Atlantic Voyages RMS

15

MORMACSCAN Atlantic Voyages Maximum Peak-to-Trough ₁₅ MORMACSCAN South American Voyages ENS

16 16 17

17

9 _{WOLVERINE STATE Atlantic Summer Port Uncotubined}

EMS 18

MORNACSCAN South American Voyages Maximum _{Peak-to-Trough}

WOLVERINE STATE Atlantic Summer P+S Combined ENS

8 _{WOLVERINE STATE Atlantic Summer P+S Combined Maximum} Peak- to-Trough

Port tjncombined Maximum

Peak-to-Starboard Uncombined ENS

18

19

Starboard Uncombined ENS, Voyage 259. 23 Starboard Uncombined Maximum

23

Port Only ENS ₂₄

WOLVERINE STATE Atlantic Winter Port Only Maximum Peak-to-Trough. ₂₄ WOLVERINE STATE Atlantic Winter New Starboard Only EMS, Voyage 277k 25

WOLVERINE STATE Atlantic Winter New Starboard Maximum

Peak-to-25

Starboard Uncombined Maximum

19

Starboard Only ENS, Voyage 267 20 Starboard Only Maximum

Peak-to-20

P+S Combined EMS: Voyage 259 21

P+S Combined Maximum

Peak-to-21

a a a a a a a a a t a a

Port Uncombined ENs, Voyage 259 .

22

Port Uncombined Maximum

(18)

Page

25 0LVER1NE STATE Pacific P+S EMS

26 WOLVERINE STATE Pacific P+S Maximum Peak-to-Trough ₂₆

27 WOLVERINE STATE Pacific Port Uncombined RMS . 27

28 WOLVERINE STATE Pacific Port Uncombined Maximum Peak-to-Trough 27

29 WOLVERINE STATE Pacific Starboard Uncombined 28

30 WOLVERINE STATE Pacific Starboard Uncombined Maximum Peak-to-Trough 28 31 WOLVERINE STATE Pacific Port Only EMS, Voyages 283, 284 29 32 WOLVERINE STATE Pacific Port Only Maximum Peak-to-Trough, Voyages

283, 284 29

AVERAGE PLOTS OF STRESS VS. BEAUFORT SEA STATE

33 MORMACSCAN EMS 30

34 MORNACSCAN Maximum Peak-to-Trough 30

35 WOLVERINE STATE Atlantic Summer EMS« , 31

36 WOLVERINE STATE Atlantic Summer Maximum Peak-to-Trough .31

37 WOLVERINE STATE Atlantic Winter EMS 32

38 WOLVERINE STATE Atlantic Winter Maximum Peak-to-Trough 32

39 WOLVERINE STATE Pacific EMS 33

40 WOLVERINE STATE Pacific Maximum Peak-to-Trough 33

41 WOLVERINE STATE Overall EMS. 34

42 WOLVERINE STATE Overall Maximum Peak-to-Trough 34

43 All Ships EMS ,

35

44 All Ships Maximum Peak-to-Trough 35

WOLVERINE STATE WAVE PLOTS

45 Voyage 279 EMS Wave Height vs. EMS Stress

46 Voyage 279 Maximum Peak-to-Trough Wave Height vs. Maximum

Peak to Trough Stress

36

47 Voyage 279 ENS Wave Height vs. Beaufort Se State.

, . 37

48 Voyage 279 Maximum Peak-to-Trough Wave Height vs. Beaufort

Sea State 37

49 Voyage 279 Estimated Wave Height vs. Beaufort Sea State

, . «.

38

50 Voyage 279 Averages of Figures 45-49 vs. Beaufort Sea State . 38

51 Voyage 283 EMS Wave Height vs. EMS Stress 39

52 Voyage 283 Maximum to-Trough Wave Height vs. Maximum

Peak-to-Trough Stress,

, 39

(19)

Figure

Page

Voyage 283 Maximum Peak-to-Trough Wave Height vs. Sea State

40 55 _{Voyage 283 Estimated Wave Height}

vs. Beaufort Sea State

41

56 _{Voyage 283 Averages of Figures 51-55 vs. Beaufort Sea State}

41

57 _{Voyage 284 pJ5 Wave Height vs. RMS Stress.}

42

58

Voyage 284 Maximum Peak-to-Trough Wave Height vs. Maximum Peak-to-Trough Stress.

. 42

59 _{Voyage 284 RNS Wave Height vs. Beaufort Sea State}

60 _{Voyage 284 Maximum Peak-to-Trough Wave Height vs. Beaufort}

Sea State

43 61 _{Voyage 284 Estimated Wave Height vs. Beaufort Sea State}

. 44

62

(20)

o (3 4.0 35 2.5 2.0 '.5 LO 0.5 o 3

BEM.FORT SEA STATE

Fig. 2. Dot Plot of Maximum Peak to Trough Stress vs, Beaufort Sea State,

California Bear,

Pacific, Voyages 25-37 CAL1FORN

BR

VOYAGES 25-37 PACIFIC UNCORRECTED-MULTIPLY BY 1.08

X-

X X .j

-

=

X-¡ .

..Xi

x (77)

i

9ZERO 1129) 1

ZERO I ZERO IZERO 125) ((4) 12) (2(3) tOlERO (53)) 12691 (6 ZERO (5ZERO CALIFORNIA SEAl. VOYAGES 25-37 PACIFIC tJNCORl.ECTED-MULTIPLY BY 1.08 3< .2 -4 .:! .=

4]

I

j

77) (241 1325 (ZaS) 1129) Iii) 29) 29) (la) (U

2 3 4 5 6 7 8 9

BEAIFORT SEA STATE

Fig. 1. Dot Plot of RMS Average Stress vs, Beaufort Sea State,

california

(21)

6.0 5.0 2.0 1.0 8.0 7.0 3.0

Fig. 4. _{Dot Plot of Maximum Peak to Trough Stress vs,}

Beaufort Sea

State,Morìnacscczn North Atlantic, Voyages 29-31

NORNAC SCAN VOYAGES 29-31 NORTH ATLANTIC NO CORRECTION FACTOR REQUIRED

X I : X 1

I..

T ... . . X.. . .. X :;: S

ï

X:

...

xl

_X.

.. (8) 2 ZEROSJ (35) 9 ZEROS (42) 2 ZEROS (62) 3 ZEROS (35) i ZERO (22) (14) ₍₎ ₍₄₎ (1) MORNACECAN VOYAGES 29-31 NORTH ATLANTIC NO CORRECTION FACTOR REQUIRED

X X

X:

X X (4) (8) (35) (42) (62) (35) (22) (14) (3) (4) (]) 2 3 4 5 6 8 10 11

BEAUFORT SEA STATE

2 4 5 6 B 9 10 11

BEAUFORT SEA STATE

Fig. 3. _{Dot Plot of RMS Average Stress vs, Beaufort Sea State,}

IJormacsccz-n North Atlantic, Voyages 29-31

4.0 3.5 3.0 2.5 2.0 1.5 LO 0.5 o

(22)

8.0 7. 0 6.0 5.0 4.0 3.0 2.0 1.0

BEAUFORT SEA STATE

Fig. 6. Dot Plot of Maximum Peak to Trough Stress vs, Beaufort

Sea State Mormacsccr.vz South Atlantic, Voyages, 27, 28,

32-38

I1ORMACS CAN

VISAGES 27, 28, 32-38 505511 ATLANTIC SO CORRECTION FACTOR REQSIRSD

Sc E 'E

==

:.="'.:1=.__.

'"

____

(39) (94) -9 ZEROS 7 ZUROS (200) (147) (36) 14 ZEROS 7 ZEROS (17) (1) (231)' 22 ZEROS MOR.MACS CAN VOYAGES 27. 28. 32-38 SSUTR ATLANTIC RO CORRECTION FACTOR REQUIRED

-. . X X T 'S_2 X _'NT

-=

-x

_)

-

-(94)

-(231) (39) - (200) 1 (147) (36) (17) (1) 3 7 8

BEAUFORT SEA STATE

Fig. 5. Dot Plot of RMS Average Stress Vs, Beaufort Sea State, Mormacscan South Atlantic, Voyages 27, 28, 32-38

2. 3 4 8 4.0 3.5 35 2. 5 2.0 o 1.5 1.0 0.5 o

(23)

3 2 e 4 WOLVERINE STATE VOYAGES 245-249, 261-265

NORTH ATLANTIC, SUMMER PORT & STARBOARD COMBINED NO CORRECTION FACTOR REQUIRED

;

(2J) os «o)

(21) (50) 03) (97) (6))

WOLVERINE STATE

j VOYAGES 245-249. 261-265

1 NORTH ATLANTIC. SUMMER PORT & STARBOARD COMMISES NO CORRECTION FACTOR RRQUIRED

J i

I

1

i

. X x ., z

-:'.J'

1 I . -: (23 (50) (73) (83 -16H (b (IS) (IO) O 2 3 4 5 6 7 B

BEAUFORT SEA STATE

Fig. 7. Dot Plot of RMS Average Stress _{vs, Beaufort Sea State,}

Wolverine States

Atlantic, Summer, Port & Starboard

Combined, Voyages 245-249, 261-265

3 4 8

BEAUFORT SEA STATE

Fig. 8. _{Dot Plot of Maximum Peak to Trough Stress vs,}

Beaufort Sea State,

_{Wolverine States}

_Atlantic

(24)

6 5 4 3 2 WOLVERINE STATE VOYAGES 245-249, 261-265

NORTH ATLANTIC SUMMER PORT UNCOMB INED UNCORRECTED-MULTIPLY BY 1.20 - -- X -= -1 X X (27)

-X ._:! X

-97) X ._z

-(61)

-

-(2fl (19) (IO) (50) (73) WOLVERINE STATE VOYAGES 245-249, 261-265 NORTH ATLANTIC, SC50R PORT UNCOMBINED UNCORRECTED-MULTIPLY NY 1.20

J

I .

I

-i .1 t -.4 1 X X (27) (50) (73) 1 (97) (6)) (2)) ((9) (IO) o 3 4

SEAUFORT SEA STATE

Wolverine State,

Atlantic, Surrrner, Port Uncombined,

Voyages, 245-249, 261-265

2 3 4 5

BEAUFORT SEA STATE

Fig. 10. Dot Plot of Maximum Peak to Trough Stress vs, Beaufort

Sea State,

Wolverine State,

Atlantic. Summer, Port

(25)

E 2 o

I

3

o

I 2

BEAUFORT SEA STATE

Dot Plot of RMS Average Stress vs, Beaufort Sea

WOLVERINE STATE VOYAGES 245-249, 261-265

NORTH ATLANTIC, SUMMER STARBOARD UN COMB INED UNCORRECTED-MULTIPLY BY 1.49 I (24) (50) (75) (97) X ..SI .1 _* $

u

I.s

e. I

l-

X 41

:;

(21) .1

i

('9) (IO) J I

BEAUFORT SEA STATE

Fig. 12. _{Dot P1st of Maximum Peak to Trough Stress vs, Beaufort Sea}

State,

Wolverine State,

Atlantic, Summer, Starboard Uncombined, _Voyages 245-249, 261-265

WOLVERINE STATE VOYAGES 245-249, 261-265

NORTH ATLANTIC, SUMMER STARBOARD UNCOMBINED UNCORRECTED-MULTIPLY BY 1.49 -e I

I

X-tmïjj (73) - X * (26) X 1$$$J

x.4

(50) (61) "IE (21) * ('9) (IO) 2 4 ₇ _E

State,

_{Wolverine State,}

Atlantic, Summer, Starboard Uncombined, _{Voyages 245-249, 261-265}

8

7

3 4 5 6 7 ₈

8

(26)

o

(0)

WOLVERINE STATE VOYAGE 267

(3)

BEAUFORT SEA STATE

Wolverine State,

Atlantic, Summer, New Starboard Only, Voyage 267

BEAUFORT SEA STATE

Fig. 14. Dot Plot of Maximum Peak to Trough Stress vs, Beaufort Sea State,

Wolverine State,

Atlantic, Summer, New Starboard Only, Voyage 267

(3)

WOLVERINE STATE VOYAGE 267 NORTH ATLANTIC SUMUER

NEW STARBOARD ONLY UNCORRECTED-MULTIPLY BY 1.01 : X

I

C

I

_X I s.

I

X _: s X s.

I

s

S s (01 (33

I

(61 (63 (10) H C,, H Q 2.0 1.5 1. 0 0.5

NORTH ATLANTIC, SUSNER NEW STARBOARD ONLY

NCORRECTED-MTJLTIPLY BY 3.01 _X s s C .

I

.. s X X s X 6.0 5.0 40 H o 3.0 H o H 'a n. 2.0 1.0 (6) (6)

(27)

4 3 i O 10 o WOLVERINE STATE VOYAGE 259 NORTH ATLANTSC WINTER FORT & STARBOARD COMBINED NO CORRECTION FACTOR REQUIRED

. s e . X e .5 s s

5

1

5555 X

II

I

X

I

IS.I

X S e S S SS X

.

I

S

e..

(12) (8) (10) (10) (6) (2) WOLVERINE STATE VOYAGE 259 NORTH ATLANTIC, WINTER PORT & STAREOARD COMBINED

NO CORRECTION FACTOR REQUIRED X

X e X

..

I X e s X S

.

_e o _.5 (0) (02) (8) (10) (10) (6) .(2) J 1 2 4 5

BEAUFORT SEA STATE

Fig. 16. _{Dot Plot of Maximum Peak}

to Trough Stress vs, Beaufort Sea

State,

Wolverine State,

_{Atlantic, Winter, Port & Starboard}

Combined, Voyage 259

i 3 4 5

BEAUFORT SEA STATE

Fig. 15. Dot Plot of RMS Average Stress vs, Beaufort _{Sea State,}

Wolverine State,

Atlantic, Winter, Port & Starboard Combined, Voyage 259 6.0 5.0 E' o o E' 4.0 30 2.0 8.0 7.0

(28)

C

0.

3

2

O

BEAUFORT SEA STATE

Fig. 17. Dot Plot of RMS Average Stress vs, Beaufort Sea State

Wolverine State3

Atlantic, Winter, Port Uncombined,

Voyages 259 8. 0 7.0 60 3.0 2.0 1.0 o WOLVERINE STATE VOYAGE 259 NORTH ATLANTIC, WINTER

PORT UNCOINED UNCORRECTED-MULTIPLY BY 1.20 s. s X X s. s s

.

s. s 5* 55.5 s X

s.

X

s

s i.. x s. X s. s.. . (171 (8) (10) (10) (65 (7) WOLVERINE STATE VOYAGE 259 NORTH ATLANTIC, '(INTER

PORT UNCOMBINED UNCORRECTED-MULTIPLY BY 1.20 B' L X

:

e. x B' X s X

_.

(0)

.

(12) (8) (10) (10) (6) (2) 2 4 5 6

BEAUFORT SEA STATE

Fig. 18. Dot Plot of Maximum Peak to Trough Stress vs, Beaufort Sea

State,

Wo7,verine State,

Atlantic, Winter, Port Uncombined,

(29)

NORTH ATLANTIC, WINTER STARBOARD UNCOINED UNCORRECTED-MULTIPLY BY 1.49

1 2 3 4 5 6 7

BEAUFORT SEA STATE

Fig. 20. _{Dot Plot of Maximum Peak to Trough Stress vs, Beaufort Sea}

State,

Wolverine State,

_{Atlantic, Winter, Starboard Uncombined,}

Voyage 259. W o o P Fig. 6 5 4 3 2 i O

19. _{Dot Plot of RMS Average Stress vs, Beaufort Sea State}

Wolverine State,

Atlantic, Winter, Starboard Uncombined, Voyage 259

X s WOLVERINE STATE

VOYAGE 259

NORTH ATLANTIC, WINTER

STARBOARD UNCONBINED UNCORRECTED-MULTIPLY BY 1.49

I

S S. S S s S

I

S X S X

.

¶ S. X

I

S X S S S

I..

I

S

I

(0) S S. (12). (8) (10) (10) ₍₆₎ ₍₂₎ 1 2 3 4 5 6 7 ra, W ç, W 3 2 1 O X s S

S..

I

X SI! S

:

X

I

S.

5

S.. X

.

¿

s

I.

(0) X (12)

s

(8) S. (10)

I

s.

_I

(10) (6) (2)

(30)

H

(3

H o

.7

BEAUFORT SEA STATE

Wolverine State,

Atlantic, Winter, Port Only, Voyages

271 ,273, 282.

(o

WOLVERINE STATE VOYAGES 271, 273, 282 NORTH ATLANTIC, WINTER

PORT GAGE ONLY UNCORRECTED-MULTIPLY BY 1.20 .1 o X - .1 X J ° ° x

x4

i

X x_ 7) (3)1 (52F 471 1X7) 2)) 08) t( (21 II) WOLVERINE STATE VOYAGES 271, 273, 282 NORTH ATLANTIC, WINTER

PORT GAGE ONLY UNCORRECTED-MULTIPLY BY 1.20

I

:___

X X .2 -X z + 2 X . 2

(7) (3)) (34) (48) (65) (20) (IX) (IS) (31 (XI II)

o 4 5 6 Io

BEAUFORT SEA STATE

Fig. 22. Dot Plot of Maximum Peak to Trough Stress vs5 Beaufort

Sea State,

Wolverine State,

Atlantic, Winter, Port Only,

(31)

O

4

2

O

4 5 6

BEAUFORT SEA STATE

Fig. 24. _{Dot Plot of Maximum Peak to Trough Stress vs, Beaufort}

Sea State,

Wolverine State,

Atlantic, Winter, New Starboard Only, Voyage 277

WOLVERINE STATE VOYAGE 277 NORTE ATLANTIC, WINTER NEW STARJISARD GAGE ONLY INCORRECTED.MIJLTIPLY BY 1.01 s s s

.

S X s.

J

?

.:

X.j:

s

..

)( :X

i

..

l

..

i 2

.

(1)

-:

(7) (19) (15

.

(18) (15) (5) (3) (3) S s WOLVERINE STATE VOYAGE 277 SORTIS ATLASITIC, WINTER NEW STARBOARD GAGS ONLY UNCORRECrED-MULTIFLY BY 1.01 2 s s x s z i S i I S

.

;

I x

..

f

8 s , s s X

:

.

X z X

,

I

.

i

2 s (1) (10) (21, (18) s (19) (5.4) (5) (5) (E)

i

3 4 5 8

BEAUFORT SEA STATE

Fig. 23. Dot Plot of RMS Average Stress vs, _{Beaufort Sea State}

Wolverine State,

Atlantic, Winter, New Starboard Ony, Voyage 277

4 o

(32)

4 8

BEAUFORT SEA STATE

Wolverine State

Pacific, Port & Starboard Combined, Voyages 279-281, p85, 286

WOLVERINE STATE VOYAGES 279-281, 285, 286

PACIFIC PORT UNCOMBINED NO CORRECTION FACTOR REQUIRED

X

-X-

-(76) (31) (6) (6) 14) 1961

I)li1

1168)

H

. . X WOLVERINE STATE VOYAGES 279-281, 285, 286 PACIFIC PORT UNCOMBINED

i NO CORRECTION FACTOR REQUIRED .

3 X

j

i . ... X

...

:1

. X I 3 (115) (f88) (196) (77) (31) (II) (6) (4) o 2 3 4 5 6 7 8

BEAUFORT SEA STATE

Fig. 26. Dot Plot of Maximum Peak to Trough Stress vs, Beaufort Sea State

Wolverine States

Pacific, Port & Starboard Combined, Voyages 279281, 285, 286 lo 9 8 7 6 5 4 3 2

(33)

BEAUFORT SEA STATE

_Wolverine

States

Pacific, Port Uncombined, Voyages 279-281, 285, 286

BEAUFORT SEA STATE

Fig. 28. Dot Plot of Maximum Peak to Trough Stress vs,

Beaufort Sea States

Wolverine States

Pacific Uncombined, Voyages 279-281, 285, 286 WOLVERINE VOYAGES 279-281, PACIFIC PORT UNCOMBINED UNCORRECTEDMULTIPLY STATE 285, 286 BY l.2Oj

I

-

1

_,

i

o.

5:'r

-i

225) - J (95) 52) (N) (IO USC) -*

I

WOLVERINE STATE VOYAGES 279-281, 285, PACIFIC FORT INCOMUSNED UNCORRECTED-MULTIPLY 286 ST 1.20

Il

o

-j

X j I

-

- °-(V 25) ) ) N)

(34)

u)

3.0

BEAUFORT SEA STATE

Fig. 29. Dot Plot of RMS Average Stress VS,Beaufort Sea State,

Wolverine State

Pacific, Starboard lincombined, Voyages 279-281, 285, 286

WOLVERINE STATE VOYAGES 279-281, 285, 286 PACIFIC STARBOARD UNCOMBINED UNCORRECTED-MULTIPLY BY 1.49 i 0 4 f at a. X . X

a

-

e . a

=

_a X -. .. .=_a a a g e e a e X

-

x .. -a a .4

a

. a

t

(521

-'

a

_a g 1133) 1204) . 1211) J J I (0) (3)) (II) (6) 4) WOLVERINE STATE VOYAGES 279-281, 285, 286 PACIFIC STARBOARD UNCOMBINED UNCORRECTED-MULTIPLY BY 1.49 X ..;:::

:

i::

X

':

... 152) (134) (239) (2O (81) (3)) (II) (6) (4) o 3 4 5 6 7 8

BEAUFORT SEA STATE

Fig. 30. Dot Plot of Maximum Peak to Trough Stress vs, Beaufort Sea State

Wolverine States

Pacific. Starboard Uncombined. Voyages, 270-281, 28S

286 (0 Q 5 o i-L) Q-X

(35)

5 3 2 6 4 3 2 WOLVERINE STATE VOYAGES 283 & 284 PACIFIC FORT GAGE ONLY UNCORRECTED-MULTIPLY BY 1.20 X t X X r X

t

(23) X i I ... (112) (82) (124) (23) (9) WOLVERINE STATE VOYAGES 283 & PACIFIC PORT GAGE ONLY UNCORRECTED-MULTIPLY 284 BY 1.20

i

-- ¿ .4 (80) -F 4 f (23) .4 (ItS) (04) (23) o 2 3 ₄ 5 6

BEAUFORT SEA STATE

Wolverine State,

Pacific, Port Only, Voyages 283, 284

o 2 3 4 5 6

BEAUFORT SEA STATE

Fig. 32. Dot Plot of Maximum Peak to Trough Stress vs,

Beaufort Sea State,

_{Wolverine State,}

_Pacific, Port Only, Voyages 283, 284

(36)

3.0 20 1.5 U.0 0.5 SS MORMACSCAN

OEUROPEAN VOYAGES. FIG. 3

O sorosANER100N VOYAGES, NYC. 5

MIXED VOYAGES, SSC 181 F102 MEAN ALL VOYAGES

EEAUFORT SEA STATE

Fig. 33. Average P1st of RMS Average Stress vs, Beaufort Sea State

Morrnacs can

10

SS MOR.MACSCAN

L) EUROPEAN VOYAGES. FOC. 4 D SOOTH AMERICAN VOYAGES FOC 6

MIXED VOYAGES ESCU8I FI C 7

4MEAN ALL VOYAGES

BEAUFORT SEA STATE

15

Fig. 34. Average Plot of Maximum Peak to Trough Stress vs,Beaufort Sea

(37)

6.0 50 4.0 3.0 2.0 10 O 2.5 2.0 1.5 1.0 05 o WOLVER NE SIATE NORTH ATLANTIC, SUNDSIR

X

PORT & STARBOARD GAGES COMBINED AND CORRECTED PORT GAGE CORRECTED

I> STARBOARD CACE CORRECTED

4

PORT GAGE UNCORRECTED STARBOARD GAGE UNCORRECTED

(61) (21) (19) (10)

Fig. 36. Average Plot of Maximum Peak to Trough Stress vs, _Beaufort

Sea State,

Wolverine State,

Atlantic, Suniïier

WOLVERINE STATE NORTH ATLANTIC, SUMMER

X PORT & STARBOARD GAGES COMBINED AND CORRECTED

<1 PORT GAGE CORRECTED

L> STARBOARD GAGE CORRECTED

4

PORT GAGE UNCORRECTED

STARBOARD GAGE UNCORRECTED

p

(2/) (50) (73) (97) f61) (21) (19) (10)

8 6

3 4 5

BEAUFORT SEA STATE

Fig. 35. Average Plot of RMS Average Stress vs, _{Beaufort Sea State}

Wolverine state,

Atlantic, Summer

3 4 5

BEAUFORT SEA STATE

(38)

8.0 6.0 H 4.0 2.0 WOLVERINE STATE NORTH ATLANTIC WINTER

X PORT & STARBOARD CACES COMBINED AND CORRECTED PORT CACE CORRECTED STARBOARD CAGE CORRECTED

4 PORT GAGE UNCORRECTED STARBOARD CACE UNCORRECTED

(0) (12)

(0)

WOLVERINE STATE NORTH ATLANTIC, WINTER

<i PORT GAGE CORRECTED

C> STARBOARD CAGE CORRECTED

4

PORT GAGE UNCORRECTED STARBOARD GAGE UNCORRECTED

(12)

(8)

t 2 3 4

BEAUFORT SEA STATE

(10) (6)

6 7

Fig. 38. Average Plot of Maximum Peak to Trough Stress vs,

Beaufort Sea State

Wolverine State,

Atlantic, Winter

(2)

i

3 4

BEAUFORT SEA STATE

Fig. 37. Average Plot of RMS Stress vs, Beaufort Sea State

Wolverine State,

Atlantic, Winter

2) (10) (10) (6) (8) 3.0 2.0 10 0

(39)

30 2.0 1.0 10.0 8(5 2.0 (47)

<1 PORT CAGE CORRECTED

t> STARBOARD CACE CORRECTED

I

PORT CAGE UNCORRECTED STARBOARD GAGE UNCORRECTED

WOLVERINE STATE PACIFIC VOYAGES

2 3

(196)

BEAUFORT SEA STATE

Fig. 39. Average Plot of RMS Average Stress vs, Beaufort Sea State

Wolverine State,

Pacific

4 5

BEAUFORT SEA STATE

(31) (6)

7 8

(4)

WOLVERINE STATE PACIFIC VOYAGES X PORT & STARBOARD CAGES

COMBINED AND CORRECTED

<1 PORT CACE CORRECTED

t> STARBOARD GAGE CORRECTED

I

PORT CAGE UNCORRECTED STARBOARD GAGE UNCORRECTED

(47) (118 (188) (196) (76) (31) (6) (4)

K

Fig. 40. Average Plot of Maximum Peak to Trough Stress vs, Beaufort

Sea State,

Wolverine State,

Pacific

(188) (118)

(40)

4

WOLVERINE STATE

o NORTH ATLANTIC, WINTER NORTH ATLANTIC SEHNTE

O PACIFIC DATA

:4111

0-

5O9

72 95 42 25 18 6 2

i.,

JOLVERINE STATE

CI - NORTH ATLANTIC, WINTER NORER ATLANTIC, SUMMER PACIFIC DATA

27 53 79 103 71 24 19 10

4 5 6 8 lo 11

BEAUFORT SEA STATE

Fig. 41. Average Plot of RMS Average Stress vs, Beaufort Sea

State,

Wolverine State

4 5 6 S lo 'U

BEAUFORT SEA STATE

Fig. 42. Average Plot of Maximum Peak-to-Trough Stress vs,

(41)

, 3 o 2 i O a 6 3 O OVERALL AVERAOIES O WOLVERINE STATE 19 VOYAGES O MORMACSCAR 17 VOYAGES CALIFORNIA BEAR 13 VOYAGES

-OVERALL AVERAGES o WOLVERINE STATE (19 VOYAGES) - CALIFORNIA ERAR (13 VOYAGES) O MORMACSCAN (17 VOYAGES> 2 4 5 6 a 10 111

SEAUFORT SEA STATE

ig. 44. _{Average Plot of Maximum Peak-to-Trough Stress vs,}

Beaufort Sea State, California Bear, Mormacscan,

k-)lverine State

3 4 5 6 a 9 io li

BEAUFORT SEA STATE

Fig. 43. Average Plot of RMS Average Stress vs, Beaufort Sea State

California Bear, Mormacsean, Wolverine State

W o

(42)

4

3

2

1.

Fig. 46. Dot-Plot of Maximum Peak-to-Trough Stress vs. Maximum

Peak-to-Trough Wave Height,

Wolverine Statç,

Voyage 279 .

WOLVERINE STATE VOYAGE 279 WAVE HEIGHT PROM - TUCKER WAVEMETER

AWi WESTBOUND ATLANTIC & PACIFIC W2 WESTBOUND PACIFIC W3 EASTBOUND PACIFIC S A A A $ . S A ASSIS S s A

AA

A*

A

S

A A S L A A

-A

U S

:A.

AUf4AI$k%

AA

U A I

Aj

I I £ WOLVERINE STASE VOYAGE 279 WAVE HEIGHT FROM TUCKER WAVEWETER -AWI WESTBOUND ATLANTIC

W2 WESTBOUND PACIFIC W3 EASTBOUND PACIFIC & PACIFIC A A SA A . A AS A S A S A S A A S LA A a A A

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RMS AVERAGE WAVE HEIGHT (FEET)

Fig. 45. Dot-Plot of RMS Average Stress vs. RMS Average Wave

Height,

Wolverine State,

Voyage 279

2 3 4 s 6

(43)

s.

BEAUFORT SEA STATE

Fig. 47. Dot Plot of RMS Average Wave Height

_Vs,

_{Beaufort Sea State,}

_Wolverine

States

Voyage 279

i

BEAUFORT SEA STATE

Fig. 48. Dot Plot of Maximum Peak to Trough Wave Heights _{vs, Beaufort Sea State}

WolverLne States

Voyage 27979

s._o .2:

X

1

..

X

I_I I I I I 4 WOLVERINE STATE VOYAGE 279 WAVE HEIGHT FROM

3 TUCKER WAVEMETER s. s 2 s s

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: : ;

(44)

O

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WOLVERINE STATE VOYAGE 279 WAVE WEIGHT FROM

DATA LOGBOOK

X

BEAUFORT SEA STATE

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Fig. 50. Average Plot of Waves and Stress vs. Beaufort Sea State

Wolverine State,

Voyage 279

A

A ESTIMATED WAVE WEIGHT

D MAXIMUM MEASURED WAVE HEIGHT

O ROIS AVERAGE WAVE HEIGHT MAXIMUM PEAK-TO-TROUGH STRESS

EMS AVERAGE STRESS A

A

C

A O

i 2 3 4 5

BEAUFORT SEA STATE

Fig. 49. Dot-Plot of Estimated Wave Heights vs. Beaufort Sea State

(45)

O

EMS AVERAGE WAVE HEIGHT (FEET)

Fig. 51. Dot-Plot of RMS Average Stress vs. RMS Average Wave Height

Wolverine States

Voyage 283

Fig. 52. _{Dot-Plot of Maximum Trough Stress vs. Maximum}

Peak-to-Trough Wave Height, Wolverine

State,

Voyage 283

I S s s u WOLVERINE STATE VOYAGE 283 WAVE HEIGHTFROM

TUCI(ER WAVEMETER

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(46)

Io

Fig. 54. Dot Plot of Maximum Peak to Trough Wave Height vs, Beaufort

Sea State, Wolveri.ne State, Voyage 283 WOLVERINE STATE

VOYAGE 283 WAVE HEIGHT FROM TUCKER WAVEMETER X

i.

:; . X x .z WOLVERINE STATE VOYAGE 283 WAVE HEIGME FROM

TUCKER WAVETER x X .:: 1 x

xj

. 9 8 7 L, 6 =_L, 5 - E-0 E-3 2 o 2 3 4 5 6

BEAUFORT SEA STATE

Fig. 53. Dot Plot of RMS Average Wave Height vs, Beaufort Sea State

Wolverine State, Voyage 283

11.2

2.9

10.1

o 2 3 4 5 6

BEAUFORT SEA STATE

9 8 7 6 5 4 3 2

(47)

X

o

_i

WOLVERINE STATE VOYAGE 283 WAVE HEIGHT FROM

DATA LOGBOOK

X

1 2 3

BEAIJFORT SEA STATE

Fig. 55. Dot-Plot of Estimated Wave Heights _{vs. Beaufort Sea State, Wolverine}

State, Voyage 283

X

[\ ESTIMATES WAVE HEIGHT

D MAXIMUM MEASURED WAVE HEIGHT

O EMS AVERAGE WAVE HEIGHT MAXIMUM PEAK-TO--TROUGH STRESS EMS AVERAGE STRESS

BEAUFORT SEA STATI

Fig. 56. Average Plot of Waves and Stress _{vs. Beaufort Sea State}

(48)

2

4

3

4

EMS AVERAGE WAVE HEIGHT (FEET)

Fig. 57. Dot-Plot of RMS Average Stress vs. RMS Average Wave Height

Wolverine State,

Voyage 284

2 1 2 3 4 5

MAXIMUM FRASi TO TROUGH WAVE HEIGHT (FEET)

Fig. 58. Dot-Plot of Maximum Trough vs. Maximum

Peak-to-Trough Wave Height,

Wolverine State,

Voyage 284 WOLVERINE STATE

VOYAGE 284 WAVE HEIGHT FROM TUCKER WAVEMETER AWi WESTBOUND PACIFIC SW2 EASTBOUND PACIFIC a s A A A A A £

AA

la 4

A A £ A A . s S $ s A A A

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q.

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A s A A A WOLVERINE STATE VOYAGE 284 WAVE HEIGHT FROM TICKER WAVEMETER

Awl WESTBOUND PACIFIC

W2 EASTBOUND PACIFIC s A A A AA A A A A A I

SA

I

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a.

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(49)

Fig. 60. _{Dot Plot of Maximum Peak to Trough Wave Height vs, Beaufort Sea State}

Wolverine State,

Voyage 284

WOLVERINE STATE VOYAGE 284 WAVE HEIGHT FROM

TUCKER WAVENETER .. X X x X X WOLVERINE STATE VOYAGE 284 WAVE HEIGHT FROM TUCKER WAVENETRR -X X X X X X 2 3 4 5 6

BEAUFORT SEA STATE

Fig.59. Dot Plot of RMS Average Wave Height _{vs, Beaufort Sea State,}

_Wolverine

State,

Voyage 284

o ₂ ₃ ₄ ₅ ₆

BEAUFORT SEA STATE 7 6 5 4 3 2 Io 9 8 7 6 5 4 3 2

(50)

o 9 8 7 6 5 4 3 2

WOLVERLNE STATE VOYAGE 284 ESTIMATES WAVE HEIGHT

D MAXIMUMHEASURED WAVE HEIGHT

O ENS AVERAGE WAVE HEIGHT MAXIMUM PEAK-TO-TROUGH STRESS

ENS AVERAGE STRESS

BEAUFORT SEA STATE

6

Fig. 62. Average Plot of Waves and Stress vs. Beaufort Sea State

Wolverine State,

Voyages 284 WOLVERINE STATE

VOYAGE 284

WAVE HEIGHT FROM DATA LOGBOOK X

-

-.

X X-X X O 2 3 4 5 6

BEAIJFORT SEA STATE

Fig. 61. Dot Plot of Estimated Wave Height vs, Beaufort Sea

(51)

APPENDIX A-1

Calibration of the CALIFORNIA BEAR GENERAL

Stress data from the CALIFORNIA BEAR is reduced based on a scale factor de-termined by the characteristics of the stress gage transducers. In order to confirm that these data do, in fact, correspond to the stress variations in the vessel, it is necessary to perform a basic calibration of the vessel by apply-ing known loads, calculatapply-ing the resultapply-ing bendapply-ing moment stresses, and comparapply-ing these computed values with stress variations measured by the instrumentation

system. Such a calibration was performed on the CALIFORNIA BEAR in August, 1968

at San Pedro, California.

Instrumentation aboard the CALIFORNIA BEAR consisted of the original slow-speed tape recorder and signal-conditioning system from the WOLVERINE STATE, plus new stress gages and transducer housings. Installation of this equipment was made in early January, 1966. _{Stress gage transducers were installed on the side} shell plates, port and starboard, midway between frames 102 and 103 in Hold No. 4 at the Second Deck level. _{The center line of the housings was 10 inches below}

the overhead. _{The stress gages were connected together in one bridge circuit to}

measure average midship bending moment stress. For further details on this instal-lation, see Lessells and Associates, Inc., Technical Report 894/i2l, "Acquisi tion and Installation of Shipboard Recording Equipment," dated January 18, 1966, the final report on Contract NObs-92l34.

PLANNING

On the recommendation of Pacific Far East Line, Inc., the naval architecture firm of Thomas T. Lunde, Inc., was asked to determine the most practical procedure for inducing the greatest possible bending moment in the CALIFORNIA BEAR during lightship condition by a loading sequence of bunkers, ballasting with water, and/ or transfer of water and fuel oil. In addition, they were asked to compute the bending moments so achieved, and to assist in liaíson between the investigators, the owner, and the shipyard.

The original plan (to perform the calibration immediately subsequent to a

drydocking) was cancelled due to shipyard delays and ship schedule commitments. On the next visit, however, it appeared that the calibration could be performed while the vessel was in San Diego. _{Accordingly, personnel from Teledyne and}

Lumide met there on August 1, 1968.

Consultation aboard the vessel revealed that bunkering facilities were inade-quate at the current location of the vessel, and it was decided to postpone the

calibration until August 3 in San Pedro.

At a meeting aboard the ship in San Pedro a detailed pumping plan was

estab-lished by Mr. _{R. McCardell of T. T. Lunde, Inc., and Mr. A. Cameron, Chief Engineer}

of the CALIFORNIA BEAR. As a result of the postponement, however, the vessel was no longer in the lightship condition, having loaded 2,642 long tons of cargo.

CALIBRATION PROCEDURE

A change in bending moment was achieved by a sequence of bunkering and bal-lasting which began at 2100, August 3, and ended at 0700, _{August 4, 1968 at the} Consolidated Marine, Inc., pier in San Pedro. _{Detailed measurements of tankage} conditions, draft, and freeboard were made, and the amount of cargo on board and being loaded during the calibration was noted. _{Weather conditions were good}

(52)

--side the vessel was 1.025. The vessel was moored port side to dock, with

negli-gible list. Computations of bending moment stress were based on the data shown

in Tables I through III.

Measurements of the changes in bending moment stress were made by noting data from three sources located progressively along the instrumentation system. As illustrated in Figure 1, these sources are:

the transducers alone

the amplifier output, and

the reproduced analog signal from the magnetic tape recording

The scale factor for converting strain indicator readings to stress is derived in

Figure 2. Scale factors for converting stress meter readings to stress are based

on the simulation of 10,000 psi stress by adding a resistor in parallel across one arm of the transducer bridge on "CAL" command. The change in amplifier output so

generated has been set to 80 divisions on the stress meter, thus giving a scale factor of 125 psi per division. To reduce the analog output on the magnetic tape

to stress, changes in signal have been scaled against this saine 10,000 psi t?CALTt

signal. Raw and reduced measurement data are shown in Table IV.

STRESS COMPUTATIONS

Stress computations were made by Thomas T. Lunde, Inc. based on the "In-tegral Factors Method." This method is presented in a paper entitled "A Simpli-fied Approximate Method to Calculate Shear Force and Bending Moment in Still Water at any Point of the Ship's Length," published by the American Bureau of Shipping in April, 1965. Displacements determined from draft readings (corrected for water density) were used to enter tables of factors for form and buoyancy. The bend-ing moments derive by this procedure were divided by the midship section modulus

(top) of 43,900 in - ft. (provided by Bethlehem Steel Corporation).

RESULTS AND CONCLUSIONS

Results of the calibration are shown in Table V and plotted in Figure 3. Inspection of Figure 3 shows that the calculations agree very well with the measured data. If the tape-recorded result (Initial-to-Final) of 3,540 psi is taken as the correct value, the other two measured values are within 6 percent, and the computed value is 9 percent high.

Measurements of plating unfairness on the SS CALIFORNIA BEAR indicate that

the measured average stress is probably 8% below the actual heart of plate stress. This brings the tape recorded and calculated stress values to within 1% of each

other.

On the basis of the unfiarness measurements and the vessel calibration, the investigators recommend that the recorded stress data from the SS CALIFORNIA BEAR be multiplied by a factor of 1.08.

(53)

B. DRAFTS

Table A-1. Initial Condition

Raw Data and Computed Stress, 2100 August 3, 1968

A. LOADING

Displacement from curves corrected for trim and density: 11,985 L.T

BENDING MOMENT at Frame 102-1/2 = 151,140 foot-tons

151,)-4Q x 2240

BENDING MOMENT STRESS - _{7,712 psi}

43,900

-ITEM TONS L.C.G. (FEET) MOMENT (FOOT-TONS)

Lightship 7,682 - 17.6 -135,203

Stores & Provisions 24 - 644

Pass. Crew Effects 15 - 225

Dry Cargo 2,642 _{- 40,870}

Fore Peak 107.8 +242.9 + 26,185

Aft. Peak 90.4 -246.8 - 22,311

#4 Deep Tank P/S 110.0 - 36.0 - 3,960

#5 Deep Tank P/S

210

- 52,.O - 1,092

Dist. Tank 20.5

+ 43

+ 88 #1 D.B. Tank 48.3 +220.1 + 10,631 #1-A

772

+195.1 + 15,062 #5 CL & S 37.9 - 17.9 - 678 #7 P/S 163.3 -152.4 - 24,&87 #1 D. Tank _127.9 _+219.7 _{+ 28,100} #IA 238.0 +194.9 + 46,386 #2. #3 P/S Settlers 217.3 - 7.8 - 1,688 #7 P/S 274.5 -170.8 - 46,843 #8 P/S 70.4 -194.0 _{- 13,658} TOTAL 11,967 - 13.83 _-165,607 FWD 14' - O 1/2" _AFT _{22' - 5"} F/A AVG 18' - 2 3/4" _{18' - 3 1/4"}

(54)

B. DRAFTS

TaL'e A-II. Intermediate Londition

Raw Data and Computed Stress, 2400 August 3, 1968

A. LOADING

Displacement from curves corrected for trim

and density: 12,070 L.T.

BENDING MOMENT at Frame 102-1/2 = 110,122 foot-tons IIQ,122 x 2240

BENDING MOMENT STRESS =

43,900

- 5,620 psi

ITEM TONS L.C.G. (FEET) MOMENT (FOOT-TONS)

Lightship 7,682

- l76

-135,203

Stores & Provisions 24 - 644

Pass. Crew Effects 15 - 225

Dry Cargo 2,660.0 - 42,569

#4 Deep Tank P/S

l054

- 36O

- 3,974

#5 Deep Tank P/s 19.4 - 52.0 - 1,009

Dist. Tank

19O

+ 4,3 + 82

#1 D.B. Tank 45.3 +220.1

+ 9,970

#1A 73.4 +195.1 + 14,320 #3 P/s & CL 94.3 + 97.5 + 9,195 #4 P/s & CL 211.1 + 37.6 + 7,933 #5 S & CL 165.0 - 19.9 - 3,278 #6 P/s & CL

3262

- 91.1 - 29,725 #7 P/s 165.9 -152.4 - 25,283 #1 Deep Tank 28.2 +219.7 + 6,196 #1A 113.6 +194.9 + 22,141 #2 & 3 P/s Settlers 211.9 - 7.8 - 1,649 #6 P/s 0.5 -141.2 - 71 #7 P/s 247.6 -170.7 - 42,265 #8 P/S 50,0 -194.0 - 9,700 TOTAL 12,258 - 18.41 - 225,758 FWD 12' - 5" AFT 24' - 3" F/A AVG 18' - 4" 18' - 4 3/8"