SOW Strain Gage.docx

Statement Of Work Strain Gage Alignment CGC Legare

PR# 2124404Y61A3799001

POC: Mr. Keith, Hare

SCOPE:

Contractor to perform strain gauge alignment checks prior to vessel dry-docking, during dry-docking and after re-floating.

As per request Maritech LLC to provide (4) strain gauge alignment measurements aboard the CGC Legare in Baltimore MD. The first measurement will be taken on or around 7/15/24 the other remaining measurements are TBD.

3.1.2 Tech Rep. The Contractor must provide the services of a Qualified Technical Representative who is familiar with the strain gauge alignment method to accomplish the following on site:

• Advise on manufacturer's proprietary system information.

• Assist with proper alignment, clearances, and repair methods associated with stern tube modification and propulsion shaft system removal and installation.

3.1.2.1 Ensure the Tech Rep has experience with the system/equipment stated above and demonstrated on their résumé.

3.1.2.2 Submit the name and résumé of the Tech Rep to the COR at the Arrival Conference.

3.1.3 Protective measures. The Contractor must furnish and install all protective measures in accordance with SFLC Std Spec 0000, paragraph 3.3.3 (Vessel component, space, and equipment protection).

3.1.4 Interferences. The Contractor must handle all interferences in accordance with SFLC Std Spec 0000, paragraph 3.3.5 (Interferences). Known interferences include, but are not limited to the following:

• Mechanical seal

• Bulkhead seal

• Shaft coating

3.2 Definitions and standard units. For the purposes of this specification and any reports generated, the following definitions apply.

3.2.1 Optimal alignment. Defined as a state of shaft alignment (through all phases of bearing wear down) where:

• Bearing loads are within a satisfactory range

• Bending stresses are minimal

• Gear box bearing loads (Fwd and Aft) always remain positive and are near equal at midlife wear

• Shaft slope through long bearings matches the bearing slope within a reasonable range

• Horizontal loads are minimized

3.2.2 Acceptable alignment. Defined as a state of achievable shaft alignment where components are constrained (movement/relocations not within work scope) but:

• Current bearing loads are within a satisfactory range and if possible remain satisfactory though continued bearing wear down

• Horizontal loads are minimized

3.2.3 Standard units. All reports, correspondences, and discussions must be in Standard/US Customary Units and not in SI/Metric Units.

3.3 Strain gauge alignment check. The Contractor must perform the specified actions in Table 1 below using Coast Guard Drawings 905 WMEC 243-001 and 905 WMEC 243-005 as guidance.

3.3.1.2 3.3.1.3 3.3.2 3.3.4 Accomplish prior to drydocking.

3.3.1.2 3.3.1.3 3.3.2 3.3.4 Accomplish prior to drydocking.

3.3.1.1 3.3.1.3 3.3.3 3.3.4 Accomplish after drydocking the vessel and before performing any hot work and/or structural modifications.

3.3.1.1 3.3.1.3 3.3.3 3.3.4 Accomplish after drydocking the vessel and before performing any hot work and/or structural modifications.

3.3.1.1 3.3.1.3 3.3.3 3.3.4 3.3.5.1 3.3.6 Accomplish in drydock after all structural and other shafting repairs and modifications have been completed, and before re-floating the vessel.

3.3.1.1 3.3.1.3 3.3.3 3.3.4 3.3.5.1 3.3.6 Accomplish in drydock after all structural and other shafting repairs and modifications have been completed, and before re-floating the vessel.

3.3.1.2 3.3.1.3 3.3.2 3.3.4 3.3.5.2 Accomplish after re-floating the vessel.

3.3.1.2 3.3.1.3 3.3.2 3.3.4 3.3.5.2 Accomplish after re-floating the vessel.

3.3.1 Shaft alignment check by strain gage method. The Contractor must furnish all necessary equipment and install sufficient strain gages, measure strains, and calculate vertical and horizontal reactions using the strain gage measurement method. Perform the strain gage measurements under the direct supervision of personnel experienced in and regularly engaged in shaft alignment by the strain gage method.

3.3.1.1 When specified in Table 1, install strain gages internally and externally to measure all internal and external bearing reactions.

3.3.1.2 When specified in Table 1, install strain gages internally to measure all internal bearing reactions.

3.3.1.3 All strain gages must remain at the same locations throughout all required inspections. Do not duplicate cost of installation if strain gauges are already installed from previous evolutions.

3.3.2 Alignment check prerequisites, afloat. The Contractor must ensure the following conditions are met for the afloat alignment check:

• All shaft components are installed.

• Vessel is in the water for at least 24 hours before alignment inspection.

• All permanent ballast are in place.

• Fuel, water, and temporary ballast tanks are filled to normal operating levels, generally half to 75% capacity.

• Vessel is on an even keel.

NOTE

It is highly recommended that the Cutter get the pre-dock strain gauge reading done in advance instead of shortly prior to the dry-docking.

• All major machinery weighing over 500 pounds is either installed or simulated by equivalent weights appropriately located

• The shafts must be free to rotate and the stern tube face seal shall not be any tighter than necessary

NOTE

Small boats are not considered major machinery and therefore do not need to be simulated by equivalent weights in their absence.

3.3.3 Alignment check prerequisites, drydock. The Contractor must ensure the following conditions are met for the in-dock alignment check:

• All shaft components are installed.

• The shafts must be free to rotate and the stern tube face seal shall not be any tighter than necessary

3.3.4 Strain gauge report. The Contractor must submit a written report of results via CFR with the following information to the COR within 24 hours after alignment check:

• All specified (i.e. external and/or internal) bearing reactions

• Deviation from specified bearing reactions in Table 4.13 of Coast Guard Drawing 905 WMEC 243-005

• A description of the alignment procedures used to obtain the bearing loads

• Strain gauge locations

• Bearing locations and reactions in shaft modeling

• Detail dimensions and configuration of the shaft model

• All mathematics values used in the shaft model such as material properties, spring constant, thermal growth effects, bearing offsets, all concentrated weights, etc

• All assumptions applied in the shaft model

• All constant values used in the shaft model

• Any indication of misalignment

• Any recommended corrective procedures. The recommended corrective procedures must include, but not be limited to: o New bearing off-sets to achieve an Optimal alignment (as defined in 3.2.1) o Other alternative to achieve an Optimal alignment o Detailed procedures to achieve shaft alignment o Table of calculated bearing wear down analysis based on prior strain gauge reports (furnished upon request by COR)

3.3.5 Strain gauge report analysis. The Contractor must provide comparative analysis of strain gauge reports as follows. This analysis may be furnished with the Strain Gauge Report described in paragraph 3.3.4.

3.3.5.1 When specified in Table 1, compare results of the “Strain Gauge Alignment Check, Post Repair” with results of “Strain Gauge Alignment Check, Drydock” and provide analysis, comments and recommendations.

3.3.5.2 When specified in Table 1, compare the findings of the inboard bearings of the “Strain Gauge Alignment Check, Post Drydock” with the “Strain Gauge Alignment Check, Pre-Drydock” conditions and provide analysis, comments and recommendations.