Enclosure_II_-_SOW_Small_Boat_Model_Tests_Rev101.docx

STATEMENT OF WORK FOR

SMALL BOAT MODEL TESTS TO SUPPORT

DEVELOPMENT OF SAFE OPERATING LIMITS

CONTENTS

1. Introduction

2. References

3. Statement of Work

4. Period of Performance

5. Deliverables

6. Schedule

7. Acceptance Criteria

8. Government Furnished Property

9. Quality Assurance

10. Security Clearance

11. Contracting Officer’s Representative

12. Notes

1.0 INTRODUCTION.

Background.

The Coast Guard Surface Forces Logistics Center, Engineering Services Division (SFLC-ESD) is cooperating with Naval Surface Warfare Center Carderock Division, Combatant Craft Detachment (NSWCCD-CCD) to develop a methodology for predicting the safe operating limits for small high-speed boats. The objectives of this project are:

1. Identify and/or develop a set of analysis tools that can be used to accurately predict the responses of small high-speed craft to various sea and wind conditions, and verify the accuracy of these tools;

2. Complete analyses for two Coast Guard cutter boats, CB- OTH-IV and LRI-II to refine the process for developing Safe Operating Limits to the point where the tools and process are suitable for routine use; and

3. Complete analyses for other Coast Guard cutter and response boats as defined by the Office of Boat Forces, CG-731.

In order to complete items 1 and 2 above, a series of physical model tests is necessary, since collection of full scale data near or above safe operating limits is not believed to be practical or safe. However, full scale data will be useful to verify the analysis and model tests reflect reality for selected cases. This Statement of Work specifies the required model test program.

2.0 REFERENCES.

1. “White Paper, Definition of Sea State Operating Limits for Cutter Boats and Response Boats”, Coast Guard Surface Forces Logistics Center, Engineering Services Division, July 9, 2014 (attached)

2. “Safe Operating Envelope (SOE) Development for the USCG Cutter Boats OTH-IV and LRI-II, USCG-USN Collaborative Effort”, Naval Surface Warfare Center Carderock Division, Combatant Craft Detachment, September 25, 2014 (attached)

3. Drawings and principle characteristics for USCG CB-OTH-IV and LRI-II (attached)

3.0 STATEMENT OF WORK.

3.1 Objectives:

Within this project, objectives of the requested model test program include:

1. Collect boat motions, attitude and relative water level data for two speeds in sea states ranging from calm water to Sea State 5 at relative wave headings of 0, 45, 90, 135 and 180 degrees (where 0 degrees is head seas) at two different loading conditions

2. Identify events and their precursors and including accelerations, capsize, broaching, surfriding, and swamping for a range of significant wave heights and modal periods at two different loading conditions

3. Perform validation of seakeeping simulations for cutter boats.

3.2 Task 1 – Test Plan Development:

Prior to starting model design, construction or test preparations, Contractor shall prepare a Test Plan that defines the following items:

1. Detailed project schedule;

2. Model Construction Plan,

3. Instrumentation list including calibration methods, calibration ranges, transducer resolution and accuracy, sensor arrangement installation details, sampling and filtering frequencies, data recording and archiving methods, and plans for quick-look data analysis at the end of each test run;

4. A list of regular waves and sea states to be calibrated used during testing;

5. Plan for video and still photography documentation of setups and tests;

6. A detailed run list for all planned tests; and

7. Specifications for data analyses for each type of test.

The test plan shall be delivered to the Coast Guard as one hard copy and one electronic copy. Comments will be provided by the Coast Guard and a revised Test Plan shall be delivered per Sections 5.0 and 6.0 below.

3.3 Task 2 – Model Design and Construction

Contractor shall design and fabricate a self-propelled model representing the CB-OTH-IV. For planning purposes, the CB-OTH-IV cutter boat is 25 feet 5 inches in length (full scale) and is powered and steered by one centerline water jet. This model shall include an autopilot for maintaining course and speed, and shall be watertight and structurally adequate for testing in large steep waves with a potential for capsize, swamping and other dynamic behaviors. Provisions shall be included for all model-mounted sensors, and model construction weight shall be controlled to permit testing at the minimum operating displacement. The model shall be watertight and the instrumentation protected in the event of capsizing. The minimum acceptable model length is 3.75 feet.

3.4 Task 3 – Instrumentation Preparation and Installation

All instruments shall be calibrated to traceable standards prior to installation and shall be installed on the model, carriage or in the basin as appropriate. Raw and fit calibration results shall be provided to the Coast Guard. All sensors shall be calibrated to read out in model scale engineering units. Table 3.1 provides a list of desired measurements and expected measurement ranges. Calibration ranges listed in the table are given as full-scale values. Note that the number and location of wave probes shall be recommended by the test facility.

Table 3.1 – Sensor List

0 to 50

Still water line to 12 inches above deck edge model scale

Empty to overflowing

Range defined by sea states

Arranged per Contractor recommendation

Video camera looking from the boat driver’s view

Video camera looking at port side of model

Video camera looking at stbd side of model

3.5 Task 4 – Setup and Testing

This task includes basin, carriage and model outfitting, calibration of all wave records prior to model installation, model, instrumentation and video setup, completion of production testing and demobilization.

Tests will be completed in regular waves and in a variety of random seas. Regular wave tests shall include a minimum of 1 pass in the test basin for each test point. In cases where nonlinear behaviors are observed at a particular test condition, in regular waves, up to 4 additional passes shall be performed at the same test point to confirm/clarify the nonlinear behavior for no more than 20% of the regular wave runs.

Random sea tests shall capture at least 180 wave encounters or have durations not less than 30 minutes full scale and not less than five wave realizations. Random wave tests shall include the deterministic validation approach documenting initial conditions and the local wave characteristics of the wave(s) present during capsize, broaching, surfriding and swamping events. When random sea tests are completed using multiple passes in the test basin, separate wave records shall be used such that the total test time series is non-repeating.

Random seas shall be created to represent a Bretschneider or Joint North Sea Wave Observation Project (JONSWAP) Spectrum with the specified significant heights and modal periods. Sea conditions for testing are listed in Table 3.2.

Table 3.2 – Full Scale Wave Conditions

Testing shall include the following groups of tests:

1. Measurement of model mass properties in air, inclining tests in calm water, natural period tests in calm water, and roll decay tests in calm water, for two loading conditions;

2. Free-running seakeeping tests at headings of 0, 45, 90, 135, 150, 165, and 180 degrees for all wave conditions in regular waves listed in Table 3.2. NOTE: 0 = Head Seas; 180 = Following Seas.

3. Free-running seakeeping tests at headings of 0, 45, 90, 135, and 180 degrees for the Bretschneider and JONSWAP wave conditions in irregular waves listed in Table 3.2. NOTE: 0 = Head Seas; 180 = Following Seas.

4. For each set of wave conditions, 2 speeds will be specified based on analysis completed prior to testing by the Coast Guard (8 and 15 knots for planning).

5. These tests will be completed at full load and minimum operating condition loadings for the CB-OTH-IV.

Unpowered, free-floating seakeeping tests shall be completed in beam waves in Sea States 4, and 5 as described in Table 3.2. The duration of these tests shall be 30 minutes full scale and model heading shall be limited using “soft springs” or an equivalent method. The spring stiffness shall be measured (i.e. surge, sway and roll) and documented for the configuration with the model set up in the water.

In addition to ship motions statistics, motion transfer functions shall be derived from this data set. Events listed in Section 3.6 shall be identified during the testing and data analysis. Individual test runs in waves shall be stopped after a complete capsize, pitch pole, or swamping that leads to a significant change in the nature of motion behavior and statistics for that run. After stopping the individual test run, the model shall be dried out, inspected for damage and the next test run started.

During execution of the test program quick-look data shall be provided immediately after each test including statistics for all channels during the quasi-steady test period and selected time histories for individual data channels.

3.6 Task 5 – Data Analysis and Report

Data analysis and reporting shall be completed in several phases:

1. The test logs, statistics, time history data files (text) and video recordings for all tests shall be delivered as soon as possible after completion of each test series;

2. Other data products including wave spectra, response spectra, response amplitude operators and phase angles shall be delivered to the government as available prior to delivery of the final report;

3. The events and related precursors shall be documented in the report along with the local wave characteristics at the time the event occurs. The events of interest and their related criteria for identification is shown in Table 3.3.

Table 3.3 Events of Interest and associated criteria

4. A draft final report shall be delivered that includes documentation for all test procedures, setups, instrumentation, tests completed, and analysis methodologies. Appendices shall be provided that include all analysis products specified above. Note that the final report does not need to summarize or explain results of the test program. It is intended to provide documentation in sufficient detail such that the experiments can be repeated using analysis tools to predict statistics and events. The uncertainty levels in the results can be quantified.

5. The draft report shall be delivered as 1 hard copy and 1 electronic copy. A final version shall be prepared and delivered after receipt of Coast Guard comments.

3.7 Task 6 – Perform Seakeeping Validation Simulations

Contractor shall perform validation simulation comparisons using a time domain 3D potential flow seakeeping code. Seakeeping simulations shall duplicate the model test cases of at least 30 regular wave runs and at least 15 irregular wave runs. Comparisons between the simulations and the model tests shall be documented in a report.

4.0 PERIOD OF PERFORMANCE.

4.1. Period of performance shall be 365 days after contract award.

5.0 DELIVERABLES.

5.1. The contractor shall provide the deliverables listed in Section 6.0 below.

6.0 SCHEDULE.

DACA is calendar days after contract award.

NLT is no later than.

7.0 GOVERNMENT FURNISHED PROPERTY.

None

8.0 QUALITY ASSURANCE.

8.1. The contractor shall apply International Towing Tank Conference (ITTC) standards for Seakeeping and capsize model construction and testing accuracy. The USCG will attend the model tests as observers.

9.0 SECURITY CLEARANCE.

9.1. Security clearances are not required for this project.

10.0 CONTRACTING OFFICER’S REPRESENTATIVE.

10.1. The Contracting Officer’s l Representative (COR) at the U.S. Coast Guard Surface Forces Logistics Center will be Mr. William L. Thomas, SFLC-ESD-NAME-NAV ARCH, (410) 762-6717.

10.2. The Alternate Contracting Officer’s Representative (COR) at the U.S. Coast Guard Surface Forces Logistics Center will be Mr. Karl Stambaugh, SFLC-ESD-NAME-NAV ARCH, (410) 762-6910.

11.0 NOTES.

None