Collective Contractor Questions and Government Answers.docx

Collective Contractor Questions and Government Answers

1. We are unclear as to how “two fixture” operation is performed.

A. Do fixtures operate on two separate SPMTs?

B. Do they need to accommodate dual SPMT transportation?

Please clarify the question.

C. Are synchronized controls between both fixtures required?

D. How does the customer envision dual fixture operations?

A.

Yes, two SPMT trailers will be used during each shafting evolution. Each trailer will have a PPU attached, and a shafting fixture installed. The saddle of the shafting fixtures will be positioned on the shafts to capture the C.G. The distance that each SPMT trailer is apart will vary based on the shaft length and viable means of saddle placement (e.g. if the saddle can’t be used on a sleeve or not). The SPMT trailers will be in “free mode” per the OEM’s guidance. They will not be physically coupled during the operation. They will be linked using a data cable and then programed based on their coordinates/relative position. This means that two trailers will be programed to operate in synch on one controller during operations. This control method would let the FWD and AFT SPMT trailers independently rise and lower from each other.

Note that historically, C740 operations has been elected to utilize independent operators for our past evolutions. The control of each SPMT trailer with a separate controller is a possibility; however, it is not the preferred method.

B.

Desire is for each fixture to be mounted on a single trailer. Two fixtures/trailers are required to handle a single shaft at a given time. See the above response. SPMTs will be able to raise/lower and rotate independent of each other. The shaft fixtures will need to account for the lateral forces transferred through the shaft induced by travel, rotation, braking, etc.

C.

Yes, each fixture will require the independent ability to raise/lower as well as a synchronized raise/lower function. If a synchronized raise/lower feature is not feasible to provide, then each fixture will require a means for the operator to validate levelness and the height differential between its sister fixtures during operations.

Note that the speed of all functions can be adjusted (raise/lower and travel) of each SPMT unit. And as noted in question 1, operators tend to individually operate 2 SPMT units. So, keeping the same parameters on both SPMTs is critical.

D

Each trailer/fixture can be operated independently. Desirable to be able to sync, for example raising both 2’, then stop and operate independently if needed.

The fixture itself will have a raise, lower, and a side to side shifting function and will allow for some degree of rotation or translation in the shaft saddle.

See the above responses. The intent for operations is to start with both SPMT trailers at the same level trailer height based on the shaft’s build height. To simplify the operations and reduce risk, the goal is to have the two fixtures provide most of the the raise/lower height changes through their own function. This is also driven by the need for precision control on the raise/lower function to align the shafts.

1. The 15 Kip load at the top in the lateral load would seem to require outriggers or setting the fixture on its legs (due to the narrow SPMT, depending on the stability requirements). Is the load truly “any direction”?

This lateral load would be mainly in the FWD/AFT direction of the trailer body. Operations would require the longitudinal axis of the trailer to be aligned with the direction of pull/push. This 15 KIP pulling/pushing force would not be needed to be analyzed over the trailer’s short axis. The shaft fixtures will need to account for the lateral forces transferred through the shaft induced by travel, rotation, braking, etc.

We can drill down on all precise shipyards design needs, possibilities, and all other questions the contractor may have once the contract has been awarded. Listed in section 4.1 of the SOO NNSY and the awarded contractor shall have collective communication back and forth to ensure all stack holds are on the same page. The shaft dollies themselves are a design effort where details such as this will be collectively discussed. It’s the Governments expectation that the proposed contractor, advise the Government on what’s possible and what is not possible.

1. How much FWD/AFT translation needs to be accommodated?

Approx 18”. Shaft should be lockable to the saddle to resist un-intentional slippage during SPMT travel. This lock should then be easily removable during operations.

1. Is there an envelope drawing available? We envision that adjacent shafts or hull structure will restrict the available envelope.

After award site needs such as the available work area / envelope will be provided, these questions and concerns will be shared with the contractor on a need-to-know basis. The Government has (NOFORN) No Foreign Dissemination requirements.

5. The 360-degree rotation about a horizontal plane is not clear. Typically, rotation would be “in a plane” or “about an axis”. Please clarify intent.

With shaft stationery, the SPMT could rotate 360 degrees underneath (about the axis of the shaft support) without significant movement of shaft. The intent is to have a 360° swivel at the point of the saddle where the actual shaft meets the fixture.

Is this asking you want the tables to have rotate capabilities when, if needed, rotating the entire shaft via its center point? As in the SPMTs will not be rotating 360 individually but rotating the shaft in unison?

More precise clarification and discussion will take place after the award.

6. The 8-degree rotation from vertical implies that the shaft is vertical. Was the intent 8-degrees from horizontal

Yes, the shafts operate at an upwards angle from propeller to inboard end.

7. Shaft column adjustment for “drift” is not clear. Does the fixture need to be able to adjust/ “drift” the column and supported shaft in the specified directions, or does it need to be able to “float” to accommodate “drift” being driven by an external force?

The “drift” is meant to be a fine tune when the SPMT is stationary to side shift the shaft saddle fwd., aft, port or starboard approximately 18”.

When two fixtures are moving a shaft, if one moves faster than the other, the one that has the shaft locked to the fixture will cause differential movement on the fixture that is free to slip. If it is feasible to sync the fixtures that would eliminate this undesired movement.

If feasible we are looking to have side shifting capabilities.

8. Does the “fully retractable cylinders” requirement preclude the use of single acting extension cylinders with gravity retract?

We don’t need double action cylinders. Their proposal is fine if they use hydraulics.

9. Will spill/leak containment need to be incorporated into the fixture to mitigate leakage onto the drydock?

Yes

10. Are there any EMI or electrical hazardous environmental requirements?

Yes, there is potential EMI from operating ships radar. The fixture will be used in a wet environment in the drydock.

11. Does the design need to “fail safe” of “fail operational” for single failures?

We would require limp modes to be utilized in the event of a frailer to ensure no sudden movements. We would ask to have the ability to bleed with mechanical means to lower the mechanism.

12. Will the designer be required to perform FMEA or similar failure modes analysis or will the owner perform this analysis?

Yes, paragraphs 5 and 6 of the statement of objective require the designer to perform.

13. Requirements reference “ASME”, with no particular standards listed. Please provide details.

TBD

14. Are there any special requirements related to technicians working around, near, under, or on the fixture while it is static or in motion? (man-rated, suspended loads, etc.

Yes, desire is that rigging team could “ride the fixture” to provide a viewpoint to center up the shaft in the stern tube or intermediate struts and validate clearances above and below the shaft. Preferably removable guardrails on upper platform and man-rated fall protection anchorages

15. What is the self-weight limit for the fixture?

Weight of fixture and live load of 100k must not exceed 4 axle SPMT capacity. From a transport perspective, it needs to remain under about 45 tons to lift into drydock.

16. How long are the shafts?

Details will be discussed and given to the awarded contractor on a need-to-know basis.

17. When shafts are supported by two fixtures, how far apart are the fixtures?

See above

19. What level of design is required and what type of fabrication contract is anticipated?

a. Build-to-print drawings and sub-component procurement specifications.

b. A&E level drawings and specifications requiring detailed design by the fabricator?”

The Government will be needing all drawings, models, specifications provided as a package that then could be awarded to any contractor at the Government discretion.

20. It is not clear from the Government’s solicitation what sorts of overhead obstacles exist when brought under the ship’s hull (e.g. any sort of lifting appurtenance extending above the centerline of the shaft may/may not contact the underside of the hull)

In the design of the fixture itself there can be no over the top of the shaft device. Will explain in detail after award.

21. Is the intent to have 2 SPMTs supporting either end of a single Shaft and moving in tandem around the shipyard? Our assumption is that this operation is driving the 360 deg horizontal plane rotation and +/-8 deg from vertical rotation requirements.

Yes and No

The intent is as stated “to have 2 SPMTs supporting either end of a single Shaft”.

The system will be located inside the drydock, it will not be travelling through the shipyard.

The “Job” itself is installing a shaft into a carrier. More details will be given on a need-to-know basis.

22. Regarding the FWD and AFT horizontal slip/translation requirement, is there an upper bound of desired movement in that axis or is the idea for the Shaft to be able to freely slide through the Saddle? “

The Shaft would be able to freely slide through the Saddle.

22. Is this solicitation for design only or does it also include fabrication, testing and supply?

We are looking for design first. The contractor who gets the contract awarded to them shall provide the design and may be asked to perform the build; however, the build would need to go back out for a bid. The Government does not desire to be locked in with a particular contract to be to build these fixtures. The Government will obtain all rights to solicit any capable contractor to perform the fabrication of these units

23. There is not enough time to put together a good proposal for this project, can the date be extended by two to three weeks?

Request granted by the KO.

24. The solicitation seems to imply that the shaft may be handled by two fixtures. Will the propellor shaft always be handled by two fixtures or will there be times when the shaft will only be supported by one fixture?

a. If the shaft is handled by two fixtures, do the fixtures need to be controlled simultaneously by one controller or can they be independently controlled?

The shaft will always require two fixtures.

We would like them to have the flexibility to perform function of control of possible. After the award discussion on this topic can be discussed.

25. How much forward and aft slip/transition plane is required?

The shaft will not be “locked down” to the fixture itself. The shaft shall reset in a saddle.

26. The solicitation states that the “shaft must have ability to freely rotate about horizontal plane 360 degrees and freely rotate from vertical +/-8 degrees”. Can we get some clarification on what this means? For instance, if we interpret the shaft to lie on a horizontal plane and the shaft needs to rotate 360 degrees to about a vertical axis then we would need to know how long the shaft is and if it is evenly balanced (or where the center of gravity is). We are unsure if the intent is to rotate the shaft as if on a turntable. Likewise, the statement about “freely rotate from vertical +/-8 degrees” is unclear to us. We are unsure if the intent is to tilt the shaft as if on a seesaw, and we request further clarification on this statement.

The Shaft will set in a saddle and need a pivot point at the base of the saddle. More details will be given on a need-to-know basis after the award.

27. The solicitation states that we are to provide “saddles (or multiple saddle attachments)”. Please confirm that the dimensions given are shaft diameters.

a. How many shaft sizes are there so we can know how many different saddle configurations there will be?”

Answer to A. More details will be given on a need-to-know basis after the award, more specifically the shafts, weights, lengths, and diminutions. For your purpose of providing a quote plan on 4 saddle configurations. Please use section

Please refer to the SOO for additional information.