3238 RFI 1-29.pdf

ANSWERS TO RFI 1-28 AS OF OCTOBER 19th, 2021

1. C002 VESSEL OPERATION

Specification state: “The workboat will be designed to withstand the ambient temperature range as stated by ASHRAE for Sault Ste. Marie, MI, or as otherwise described in this specification”.

Please clarify if this criterion is limited to the design of the HVAC system.

ANSWER: The entire vessel, including all exterior equipment and steel, shall be designed to withstand, at a minimum, the ambient temperature range as stated by ASHRAE for Sault Ste.

Marie, MI. This is not limited to the design of the HVAC system.

2. C004 CLASSIFICATION AND CERTIFICATION – B U.S. COAST GUARD (USCG)

/ C105 HULL GEOMETRY

Per C105 Vessel Length (molded) to be 65’ – 80’. Per C004 - The Contractor shall also be responsible for obtaining a U.S. Coast Guard Load Line Assignment for Great Lakes Service and a Tonnage Measurement.

Question: Please clarify requirement for Load Line. Per USCG Load Line Technical Manual, new vessels less than 79 feet (24 meters) in length are exempted. From previous experience USCG will not issue a Load Line for a vessel under 79 feet. Is the intent for the vessel to be 80’ with a Load Line, or for a design wherein the vessel is less than 79’ a Load Line is not required?

ANSWER: The intent is to follow the USCG Load Line Technical Manual. Therefore, obtaining a USCG Load Line Assignment for Great Lakes Service is required if the proposed vessel is greater than or equal to 79 feet. It is not required if the proposed vessel is less than 79 feet.

3. C170 DRY DOCKING PLAN / C. DRY DOCKING RIBS

Question: (1) Requirement calls for 2 to 4 rib sections. In addition to requirements to “evenly distribute the loads and avoid undue stresses within the hull structure” are there limits in loading of the frames to the lock floor and are there seismic or wind loading criteria to be applied to the design. (2) Requirement states “the ribs shall be able to be floated and attached to the vessel while afloat” – please elaborate on this requirement – can a crane be employed to handle the frames?

Are frames to have ability to self-ballast / de-ballast to be positioned? Does vessel need to be able to self-deploy frames using crane? Can we assume divers will check the rib placement or use underwater fixtures to secure?

ANSWER: Please assume a 3,000 PSI loading limitation. Frames do not need to self-deploy or be able to ballast. Design may incorporate slight negative buoyancy using closed tube framing.

Cranes will be used to install and remove the frames. The frames shall be capable of being attached to the vessel via cables, chains, or other fastening. Divers or remote operated vehicles will be employed to check the proper positioning of frames.

Please see the following pictures as reference.

Photo 1: Frame Looking Aft Photo 2: Frame Looking Fwd

4. C180 NOISE & VIBRATION / D. NOISE LIMITS

Question: (1) Section invokes ABS Guide 163 “Crew Habitability on Workboats for vessels less than 60m in length”, however in the table has sound pressure levels lower than in the referenced guide. For example, the ABS Guide (Excerpt below) has 110-dB(A) for Machinery Spaces, while the specifications invoke 100-dB(A). Additionally, exterior spaces would have an 85-dB(A) requirement versus the 75-dB(A) in the specifications.

ANSWER: Please use the following limits:

Machinery Spaces .......................................................... 110-dB(A) Crew Spaces .................................................................... 70-dB(A) Accommodation Spaces .................................................. 60-bB (A) Galley & Mess Area ......................................................... 65-dB(A) Exterior (Aft, 3 location P/S) ............................................ 85-dB(A) Exterior (Forward) ........................................................... 85-dB(A) Pilothouse ........................................................................ 65-dB(A) Exterior P/S Doors ........................................................... 85-dB(A)

5. E05 TRIALS, TESTS AND DEMONSTRATIONS / F. OPEN WATER TRIALS

(LEVEL 4) / 14 Noise and Vibration Survey

- The Specifications state “The noise and vibration survey shall be conducted under the following condition: • All ventilation equipment and systems in full operation, both propulsion engines at full speed,”

Question: Please clarify if the requirement is to meet the sound pressure levels as stated in C180 with propulsion engines at full power? Note that ABS Guide 163 states the propulsion machinery is to be at 80% MCR (excerpt below).

ANSWER: The intent is full engine power, which under normal operation is 80% MCR.

6. C200 ARRANGEMENTS / C201 GENERAL

Specifications “Clear finished headroom in all hull spaces shall not be less than 7’-6” while accommodating all necessary equipment, ducting, wiring and piping”. The description of spaces in C201 B does not define what is/are hull spaces.

Question: Does the 7’-6” clear headroom requirement apply to all areas in the hull including machinery spaces - in particular aft lazarette / steering gear compartment etc.?

ANSWER: The clear 7’-6” clear headroom requirement applies to all personnel spaces and the engine room, not including the steering gear/lazarette. Slight tapering in the bunkroom/accommodation spaces below deck near the bow may reduce headroom. In these instances, headroom shall be 7’6” at the entrance and not reduced more than 1 foot due to tapering toward bow..

7. C330 FOUNDATIONS / H. LIFTING PADS

Specification has conflicting requirements –

(1) “During construction, the COR will locate the lifting pads”

(2) “During Phase II, the design and calculations for the pads and structural reinforcement shall be developed and submitted to the COR and ABS as applicable for review and approval”

Additionally – specifications require “the structure in way of the lifting pads shall be stiffened to prevent undue deflection under expected loads”. If lifting pad locations are not defined in Phase II, contractor will not be able to incorporate reinforcing structure at the panel fabrication level.

Similarly, if the COR can change locations during construction, this may cause rework if contractor has already installed and painted any required structure.

ANSWER: The following requirement is removed: “During construction, the COR will locate the lifting pads.”

8. C405 CATHODIC PROTECTION / B. REQUIREMENTS

Specifications state “If anodes are used, they shall be manufactured and installed in accordance with MIL-SPEC MIL-A24779”

This MILSPEC cited is germane to Aluminum Anodes, which have limited efficacy in fresh water.

Magnesium anodes are more appropriate to this application, the composition requirements are defined in MIL-A-21412A (Ships)

ANSWER: Magnesium anodes are acceptable. All magnesium anodes shall be manufactured in accordance with MIL-SPC MIL-A21412A.

9. C406 / C

Specification clear regarding surface prep if choose “…. or limit initial coating to base coat only.”

What are additional surface prep requirement if choose “pre-construction primer”?

ANSWER: Prior to the application of any pre-construction primer or base coat, the surface shall be prepped in accordance with the SSPC specifications identified in C406. If a pre-construction primer is used, the surface prep prior to the installation of the full coating system shall be in accordance with the paint manufacturer’s specifications.

10. C410 / B

Require copy of COE Drawing FRE-H210-001, Ice Scraper

ANSWER: Drawing FRE-H210-001, Ice Scraper is included in the Drawings.zip folder.

However, the drawing is misnamed as “Ice Breaking Bow Steam Details.tif”.

11. C436 / E

Note that no joiner ceiling required in any location except the Pilothouse. Is this correct?

ANSWER: This is correct. Please provide sheathing over insulation in other spaces as required.

12. C460 / F

Communications Mark Dwg 611-D460-02 requires the Castle, Border & Background plate to be cut stainless steel plate. The specs call for the same items to be cast bronze. Which is correct?

ANSWER: Please follow the reference drawing requirement for cut stainless steel plate.

13. C605 / D

Torsional Vibration Analysis – specified as Phase I deliverable, should be Phase II.

ANSWER: Correct, the Torsional Vibration Analysis shall be submitted to the COR for review and approval during Phase II.

14. C662

Saw no requirement for an Oily Water Separator. Is this correct?

ANSWER: That is correct.

15. Conflict between ICE CLASSIFICATION and CONDITIONS/CAPABILITIES

Requirement to break 12” of packed ice is more in line with Ice Class A0 or B0. Ice Class C0 only describes breaking in open floes that are generally not in contact with one another.

1st year ice up to 12” is ice class C0, but only at a 6/10 coverage which is defined as open pack ice. If the requirement is to break 12” solid ice, the classification should increase to A0 or B0. See ABS references below.

ANSWER: The vessel will not be used to break 12” solid ice. Please follow the requirement to design the vessels to ABS Ice Class C0

16. Full length drip pan under the engine will be very challenging with ice class structure.

ANSWER: Please disregard this requirement.

17. Gear is required to go from full ahead to full astern 12 seconds or less. This is usually a function of the engine stalling, not gearbox capability. There is no way to guarantee 12 seconds, nor is there a way to improve it unless we add a shaft brake.

ANSWER: This requirement will be changed to “Each propeller shall be able to switch from full rpm ahead to full rpm astern in 12-seconds or less.” This requirement will be moved to C605 Propulsion Control System.

18. What is “throttle boost” listed under gear control as a mode of operation? Requirement for

“express mode” essentially requires a twin disc EC300 system. Is that the intended desire?

ANSWER: Specification Section C605 Paragraph B will be modified to:

“The Contractor shall provide and install a complete control system for each main engine and reduction gear. The throttles shall be centered on the pilothouse console. Each main engine and gear control system shall incorporate the following features:

• Set up for full electronic controls with all electronic throttle and shift

• No mechanical actuators may be incorporated into the control system

• Sequencing control system

The control system shall be configured to sequence the engines, reduction gears, and clutches to forestall the possibility of engine stall during high-speed maneuvers in emergency situations.. The control system shall be fully adjustable through software changes.

The control system shall be provided by the engine or reduction gear manufacturer. All service warranties shall be through the engine or reduction gear manufacturer. The installed control system shall meet the recommendations and practices of the engine, gear, and control system manufacturers.

The Contractor shall supply one control system station to be located in the pilothouse. The control station shall be equipped with two single lever control heads, one for each engine.

Power for the control system shall be set up such that:

• The power supplied is from a clean source.

• Back up source of power is automatically transferred to in the event of a loss of primary power.”

19. Propeller speed requirements aren’t descriptive enough. It would be better if USACE could dictate whether the preference is for bollard pull or top speed. 12 knots open lake speed will be very challenging. Is this a max required speed or intended transit speed? What is desired cruise speed? What is desired bollard pull?

ANSWER:

20. Spec calls for struts to penetrate the hull and weld directly to girders. Would USACE consider landing on doublers externally and having the struts inline with the girders?

ANSWER: Please follow the requirement for struts to penetrate the hull and weld directly to girders.

21. Steering system is specified as 120/240V. This system will likely need 5+hp HPU pumps.

5 hp pumps would be better at 480V and can be natively powered from the 480V switchboard.

ANSWER: Please disregard the requirement for specific voltage for the steering system.

22. Rudders are to be independently controlled. This will force additional steering piping and additional complication. Why independent control? Is there an anticipated use case for single rudder control?

ANSWER: Please disregard the requirement for rudders to be independently controlled.

23. Spec calls for a fuel purifier – is local fuel quality an issue where filtration alone is not enough? No. 2 diesel is widely available and generally very clean. The purefier will consume additional space in the engineroom, which is already tight.

ANSWER: Please disregard the requirement for a fuel purifier.

24. Fire monitor requires 1200 m3/hr (5280 GPM) from a positive displacement pump. This is not practical. This should be a centrifugal pump, and at this size will require a stand-alone diesel to power it 6-700 HP expected power requirement. Not a good idea for this size tug. 1500 GPM would be much more typical for this size vessel.

ANSWER: Specification Section C675 Paragraphs E and H will be modified to:

E. FIRE PUMP

The Contractor shall supply and install two (2) fire pumps in accordance with ABS and USCG Subchapter M requirements. At least one (1) pump shall be an independently driven, self-priming, centrifugal pump with cast iron housing and bronze impeller. The second fire pump may be driven by a main engine..

A combination of fire, sanitary, ballast, bilge, or general service pumps may be used to satisfy the requirements for the fire monitor identified in part H of this section.

The independently driven fire pump shall be electric drive type, with the pump and motor furnished as a matched set from the pump manufacturer. The motor controller for the pump shall be set-up with low-voltage release. See Contract Section C750.

The flexible connections/expansion joints to the pumps and throughout the system shall be single sphere EPDM flame resistant ASTM F1123-87. The joints shall be wrapped in an A-60 equivalent fire rate blanket, aluminum faced, ABS type approved.

A relief valve shall be provided and installed on the discharge of the fire pumps that relieves overboard of the vessel. The relief valves shall be provided with isolation valves and an emergency bypass valves. A pressure gauge shall be fitted on the discharge side of each fire pump.

The electrical overload protection on the fire pump shall be removed.

The fire pumps shall be capable of being started and stopped locally and from remote locations as follows:

• Locally by the fire pumps

• Remotely in the pilothouse

• Remotely on the main deck near the fixed fire extinguishing system pulls

The remote control shall be capable of both starting and stopping the fire pumps. Each remote control shall have a green running indication light.

A placard shall be located at the fire pumps indicating that the isolation valve downstream of the fire pumps shall always remain open, except for during maintenance periods.

H. FIRE MONITOR

One (1) remote controlled fire monitor shall be installed on the forward pilothouse top. The controls for the monitor shall be located in the pilothouse. Final location of the monitor and its controls will be approved by the COR.

The fire monitor shall be sized to be capable of reaching a throw length of 225 feet and throw height of 100 Feet. Pump requirements for the fire monitor are provided in the Fire Pump section above.

25. HVAC requires a ductless split system with hot water coils. We are not aware of a commercially available system that combines an exterior AC system with a boiler heat in ductless units. The section then goes on to specify air handling units with belt driven fans.

This is inconsistent with a ductless system. Please specify ductless or ducted air handlers, cannot be both.

ANSWER: Specification Section C685 Paragraph C will be modified to:

“The Contractor shall provide and install all components necessary to form a complete heating, ventilation, and air-conditioning system for all spaces in the deckhouse, including the pilothouse and all accommodation spaces. If accommodation and living spaces are in the hull, they shall receive the same system as described in this section.

Based on the above load calculations, equipment shall be selected for a ductless direct expansion cooling and hot water heating system. The HVAC system and all equipment/components shall be installed in accordance with the manufacturer’s installation manual.

The HVAC system shall consist of indoor fan coil unit(s), outdoor-mounted air-cooled condensing unit(s), and digital controls. Each indoor unit or group of indoor units shall be independently controlled. Hot water shall be supplied by a hot water boiler (see Paragraph I).

The indoor fan coil units shall have the following features:

• Factory assembled, wired and run tested. Contained within shall be all factory wiring, piping, cooling coils, hot water heating coils, expansion device, control circuit board and fan motor.

• Mounted so to minimize vibrations.

• The indoor fan shall consist of a minimum of three speed settings (Low, Medium, and

High)

• The coils shall be of nonferrous construction with smooth plate fins on copper tubing.

• A condensate pan and drain shall be provided under the coils and be able to operate in out of level trim conditions (see additional info below on condensate drain requirements.) The condensate pan shall be constructed of stainless steel.

• All refrigerant lines and hot water lines shall be insulated.

The outdoor condenser units shall have the following features:

• Insulated refrigerant lines.

• Accumulator with refrigerant level sensors and controls.

• Vibration isolator mounts on the compressors

• Painted, galvanized steel cabinets

• High and low-pressure switches

• Anti-short cycling protection

• Compressor overload protection

The selection of a mounting type (floor, ceiling, or wall) for each fan coil unit shall be based on minimizing the unit’s obtrusiveness in the space it is serving.

Each condensate line from each fan coil unit shall be insulated. The condensate line from each fan coil unit shall drain together into a common header with the common headers discharging overboard. The condensate drains from the fan coil units shall not be combined with any other systems’ overboard discharge lines.

Non-sweat fiber line shall be used for the condensate lines passing through the bulkheads and the decks.

System commissioning and startup shall be performed by the HVAC equipment manufacturer and/or manufacturer authorized factory representative.”

26. Is an upper pilothouse acceptable to meet the specified 20-foot height of eye requirement?

ANSWER: Yes, an upper pilothouse is acceptable to meet the specified 20-ft height of eye requirement.

27. The Spec calls for a Load Line assignment, but the tugs to be built will have a resulting regulatory length below 79-feet. The USCG will not issue (voluntary or otherwise) a Load Line assignment to any tug below 79-feet in length. We ask that this provision be removed.

ANSWER: The intent is to follow the USCG Load Line Technical Manual. Therefore, obtaining a USCG Load Line Assignment for Great Lakes Service is required if the proposed vessel is greater than or equal to 79 feet. It is not required if the proposed vessel is less than 79 feet.

28. We hereby request an extension to the bid due date of at least one (1) additional month, which will be required to complete a detailed cost estimate and prepare a responsive and competitive proposal.

ANSWER: The bid due date will be extended.

29. We ask if proposals can be submitted via email

ANSWER: Yes, email submissions are acceptable.