1. MOBILE OFFSHORE BASE (MOB)
ONR S&T Program
Overview
Office of Naval Research
The purpose of this briefing is to provide an overview of the ONR Science and Technology program, which has been underway since February 1997.
The first grant was awarded in March and the initial contract awarded in July In the subsequent 2-12/ years approximately 75 grants and contracts have been awarded towards the goal of assessing MOB feasibility and cost.
The Naval Facilities Engineering Service Center (Port Hueneme CA) coordinates the technical program for ONR.

2. * http://mob.nfesc.navy.mil
ONR MOB S&T Program
Follows DARPA Program ( )
ONR S&T Program ( )
Objective:
Establish Feasibility and Cost of MOB
Approach:
Open, Collaborative Teaming among Industry, Academia, and Government
Data and Technical Documents immediately available on the WEB * *
This visual presents a broad overview of the resources associated with this ONR S&T program.
The objectives are very general. In fact, this generality had a major impact on the program direction. The S&T program direction was dictated by two overriding factors: (1) these general objectives, and (2) the absence of clearly-defined missions.
The main block of FY96 funding, potentially available in Oct 1995, was sent to ONR 16 months late, arriving Feb The S&T program was initiated at that time. Note that $300K had been released the previous Sept to allow for review of the 120+ preproposals submitted in response to an ONR MOB BAA in May 1996.
Present S&T funding will be exhausted by Summer 2000.

3. MOB General Mission
Provide a floating, in-theater platform for U.S. and Allied Forces for operational and sustainment basing capabilities in support of:
Flight Operations
Ground Troops
Equipment Storage
Supply & Maintenance
Fleet Operations
This general mission was derived from the Mission Needs Statement, dated 15 September 1995 (not JROC approved). It was initiated by Admiral Owens and signed by by 4 flag officers:
CINC Special Operations Command
CINC U.S. Southern Command
CINC U.S. Atlantic Command
Commandant United States Marine Corps

4. A Unique Ocean Mega-Structure
40 year life
Reconfigurable versus mission
Support fixed wing cargo aircraft operations up to SS6
Large volume required for storage
Support a full
Army Brigade
Ship-to-ship cargo transfer up to SS3
Exceeds Industry Practice
Survivable in
hurricanes and typhoons
and equipment maintenance
An ocean platform capable of satisfying the MOB general mission would be unique/unprecedented in terms of both size and capabilities. It would be an innovative structure both in design and function.
This viewgraph shows
upper quadrant: some of the “design driving” mission requirements and
lower quadrant: key technological challenges.

5. MOB Module & Platform Size
Semi-
submersible
300m (DB102)
VLCC
455m (Seawise Giant)
CVN
320m (Nimitz)
M O B
Semisubmersible Modules
m length
m beam
13-35m draft
This visual compares MOB to the marine industry state-of-practice using size as the single criterion. The top part of this visual illustrates state-of-practice as measured by the largest floating: semisubmersible, commercial vessel, and military vessel.
The lower part illustrates a range of possible MOB module and platform sizes. MOB modules will be semisubmersible modules, with platforms assembled from multiple modules. For some missions one module could be sufficient (striped box above), while for others, like landing a C-17, a nominal 6000ft multi-module platform may be required.
Note that even the individual modules would be slightly larger than any existing floating maritime structures. The C-17-capable 6000ft platform is clearly well beyond industry state-of-practice.
Platform Configuration
m length
1 to 5 modules
Rigid/Hinged/Bridged/DP Connectivity

6. Concept Configurations
Single Module
Two Modules
Hinged Platform
Bridged Platform
A full-length, full-depth monohull would have very large, unacceptable structural stresses along the keel due to simple hog and sag deflections. Therefore, we are looking at a range of linked modules to provide structural compliance and mission versatility. Compliance reduces structural stress in the hull, but results in relative motion between the individual modules and thus a deck that may not always be straight or continuous. Acceptable system platform concepts are those that seek a balance between structural stresses and inter-module motion.
Each semisubmersible module consists of a box type deck supported by multiple columns on two parallel pontoons. When on site, the module is ballasted down so that the pontoons are submerged below the surface wave zone. The columns provide a minimum exposed surface thereby minimizing wave loads. The decks, which store rolling stock and dry cargo, are all located above the wave crests. The columns provide structural support and hydrostatic stability against overturning. Liquids are stored in the pontoons and columns, eliminating most below water voids and thus minimizing greatly the danger of damage due to flooding. When transiting between operational sites, the unit is deballasted and travels with the pontoons on the surface much like a catamaran.
Dyn. Pos. Platform

7. MOB Topics Related to JLOTS
Requirements Derivation
Operational Availability Modeling
Cargo Transfer
Constructability

8. Requirements Derivation Process
Mission Needs Statement (MNS)
CONOPS
Mission
Analysis
Requirement
Functional
Synthesis
& Concepts
Engineering
Design Criteria
Requirements
Functions
Functional RequirementsDATABASE
Broadly Stated
Objectives
Decomposed into Specific Engineering Design Requirements
Problem:
Different interpretations of the MNS led to different design goals by the concept designers, which makes the concepts difficult to compare.
Solution:
A systems based process was developed to derive MOB mission-based functional requirements.
. Decompose MNS into discrete Missions (CONOPS)
. Define specific capabilities to support each mission (SCD)
Example (C4I, selective offload capability)
. Analyze each system capability to derive specific physical requirements. These are all documented in the DATABASE. New missions can be built from the list of elements in the database.
Example (space for troops to accommodate a particular mission)
4. PRD: One for each CONOPS: Defines MOB in terms of functional and performance requirements. Includes (doc’s, Mission rqts, Op Env., Funct. Rqts, Arrangements)

9. Requirements Derivation Process Documented in Database Structure
Contents of Requirements Database
(MNS)
(CONOPS)
(SCD)
Example of Requirements Derivation Process, Illustrating Database Structure:
MOB may have many mission, as identified in current MNS. For example, one mission may be: MOB AS LOGISTICS HUB (highlighted box). The different missions shown on this level of the tree chart would be comparable to those expressed in a document on the level of a MNS.
Each mission comprises several mission elements, for example, mission elements of MOB AS LOGISTICS HUB might include Conduct arrival/assembly ops at sea, re-constitute in-theatre, reinforce amphibious task force, etc. These mission elements would be comparable to those described in a CONOPS for a given mission.
Each mission element is tied t o specific capabilities needed to satisfy that mission element. Continuing the example, capabilities required to meet the mission element “Reinforce Amphibious Task Force” (highlighted box) might consist of those shown in chart above. These capabilities would be comparable to those described in a SCD for a given mission.
Each Capability has specific functional requirements tied to it. Continuing example, Capability “Stow Vehicular Cargo”, in supported by the specific functional requirements shown, e.g., ventilation system, loading, clear height, etc.
Dashed white line encompasses database contents: mission element, capabilities, and functional requirements.

10. Supply and Sustainment
Notional MOB System Capabilities to Support - Operational Maneuver From The Sea (OMFTS)
Supply and Sustainment
Receive, store, issue, and re-supply material for MAGTF operations for 60 days, Interface with Strategic Sea-lift and Air-Lift
Maintenance
I-Level for all MAGTF Aircraft, Vehicles and Combatant Craft
C4I
Control MAGTF throughout Area of Operation (AO), Coordinate with CJTF supporting forces
Health Service Support
Routine and emergency medical care
Other
Administrative and personnel support to keep combat forces fully operational
Slide illustrates notional Systems Capabilities to support one representative mission (OMFTS).
EXAMPLE

11. Major Mission Specific Capabilities
Logistics (CVBG)
Daily Cargo Through-put in support per CVBG
Provision/Store
24 Metric Tons
DFM
580,000 Liters
JP5
1 Million Liters
Ordnance
150 Metric Tons
SOF
Up to 10,000 SOF personnel
74 Rotary/Fixed-wing aircraft, 22 combatant craft
Water
6 Million Liters
Fuel & Dry Cargo for SOF equipment
40.5 Million Liters
9,700 Metric Tons Cargo
OMFTS
Up to 20,000 MAGTF personnel
128 Rotary/Fixed-wing aircraft, 62 lighterage
Strategic Sealift and Airlift (C-17 capable)
Water
24 Million Liters
Fuel & Dry Cargo for MAGTF equipment
67.5 Million Liters
16,200 Metric Tons Cargo
Slide shows some of the more significant (in terms of MOB size and function) capabilities required for 3 of the CONOPS. [Follow-on step to previous visual.]
Note: Strategic Sealift (C-17) capability is listed for OMFTS. Accomodating the C-17 needed to be included somewhere to show all MNS derived requirements and this was selected. You will see the impact of removing this capability on the next slide.
EXAMPLE

12. 2nd of 2 Executive Summary Visuals PENDING COMPLETION OF S&T
Mob Size & Cost Ranges
$1.5B
SOF
OMFTS
$2-3.0B
$2-3.0B
LOGISTICS
OPERATIONAL BASE
$4-5.0B
C-130 Capability
2nd of 2 Executive Summary Visuals
This slide graphically displays the same information as the previous visual. It clearly shows that MOB size, cost (as well as risk) are tied directly to the four representative mission requirements via the platform estimated lengths, and vary dramatically depending on the mission.
If we extract the C-17 capability (but retain a C-130 capability) from OMFTS, the size is halved from 6000 ft to 3000 ft.
The “Operational Base” combines all the capabilities of SOF, OMFTS and Logistics (C130 capability is included).
3000-ft seems to be the approximate divider between confident design today, and the introduction of some uncertainty pending completion of the S&T.
Costs are VERY approximate, and include the bare hull and basic machinery only.
C-17 Capability
$8.0B
3,000
2,000
1,000
6,000
4,000
5,000
RISK:
ACCEPTABLE
PENDING COMPLETION OF S&T
PLATFORM LENGTH (FT)

13. Operational Availability Model
Assess the performance of any MOB concept relative to the Mission Needs Statement
Investigate the sensitivity of various performance parameters to changes in Concept Configuration and Mission Requirements
Status:
Preliminary model - Sept. 98
Generalized model & Report Dec. 99
Input Data files - Feb. 00

14. Reliability Available Time Maintainability Repair Time
What is Ao?
“Failed”
“Repaired”
“Failed”
Logistics
Delay
Time
Repair
Time
Available Time
Time
Available
Time
Ao =
Total Time
Reliability Available Time
Maintainability Repair Time
Supportability Logistics Delay Time

15. Operational Availability (Ao) Model
Wind/wave/current
Databases
Large-scale
Typhoon scale
Operational Availability Model (AO). This tool statistically estimates the percentage of time the MOB can perform a given mission. The model considers the failure rate of key systems or components, the percentage of time lost to bad weather at the designated location, and other factors that affect mission performance. The model has not been used for full formal analysis of any concept.
This may be the first time an operational availability model has integrated mechanical and structural reliability with actual environmental data.
This Performance Assessment model incorporates input from various other product areas of the MOB Program such as:
Hydrodynamic analysis of platform motions
Metocean (wind/wave/current) data from 23 sites around the world
Air Operations Criteria for allowable runway misalignment
Cargo transfer rates for LO/LO RO/RO and Air Cargo
Quantify performance versus
Platform configuration,
Metocean characteristics of various sites,
Mission Requirements

16. Preliminary Ao Statistics - Site Comparison
(Hours)

17. Ship Cargo Transfer Rate Model
Create an analytically robust method to estimate cargo transfer rate between MOB and auxiliary vessels under variety of environmental conditions
Status
Preliminary Model and Interem Report delivered - March 99
Ship Motion analysis
completed - Aug 99
Final Model and Report
due March 00

18. Overall Modeling Strategy
Vessel Response
Environment
Motion Calcs
Transfer Simulation
Rate
Xfer Schedule
Cargo Xfer Method
Cargo Description
Cargo Movement Plans

19. Container Movement Steps
1. Lift to travel position
2. Move to target
3. Focus on target*
Insert in Cell Guide*
Lower in Cell Guide*
4. Latch
Lift in Cell Guide*
5. Lift to travel position
6. Move to unload
7. Drop to unload
8. Unlatch
9. Store on MOB
( *Gated operation ) 1 2 3 5 4 6 7 8
MOB
Robo Crane 9

20. Cargo Transfer Rate Model Conclusions
Simulation works as tool for determining transfer rate
Preliminary results
Expect about 29 containers / hr as maximum transfer rate on MOB
Motion compensated crane design is likely choice for MOB, with manual backup capability
Capability of crane designs to acquire target should be focus of crane-testing programs
Model needs to be calibrated from field test data

21. Cargo Transfer to Landing Craft
Focus: Assess ability to transfer cargo to small landing craft alongside MOB
Issues:
size of MOB allows for unique open sea cargo concepts
MOB does not move -good
large hull amplifies waves - bad
physics of vessel to vessel interaction poorly understood
unique berthing requirements
Products:
wave characterization around MOB
wave sheltering concepts
The primary mission requirement for the MOB is to store and transfer cargo as a logistics facility. Traditionally, the effectiveness of open-sea cargo transfer depends heavily on the high relative motion between the transferring vessels. A very large semisubmersible type vessel like MOB does not move much for metocean conditions where cargo transfer is desired, thus minimizing this problem. However, recent hydrodynamic studies have indicated that wave patterns around the large semisubmersible columns of a MOB could amplify the wave environment for smaller vessels attempting to load or unload alongside the MOB .
Some potential solutions have been proposed, including methods of forming a protected harbor and improving the motion compensation capability of handling equipment. As shown, vertical walls can act as effective shelter for small vessels alongside MOB. Temporarily lowered like garage doors between the columns of MOB, these walls need only extend part way to the pontoons to be effective in reducing the local wave environment.
Vertical wall sheltering

22. Typical Relative Water Surface Contour Plot Base Case – 6 Second Waves - 30 Heading
Typical qualitative results
Results vary dramatically with heading and frequency
Visually not obvious which is best configuration, heading, loading location.
Therefore went to numerical evaluation by averaging surface over specific loading locations.

23. Comparison of RMS Ramp Angle (Heading With Lowest Motions)
Ramp angles are not only worse than walls, but are higher than the base case
Hypothesized due to waves reverberating in enclosed box and interaction between vessel bottom and lagoon bottom
Lagoon concept probably needs door
Transmission Coeff Is Misleading - Must Calculate Vessel Motions

24. Constructability
Concluded that U.S. industry has capacity to competitively deliver a CTOL-length MOB platform
Developed a risk-based constructability model and guidelines
facility capabilities
transportation
environmental impact
safety
management
cost and scheduling

25. MOB Program Summary Pioneering marine technology advancements
Products emphasize general applicability, ranging from mission planning to fabrication
Advancements also applicable to other maritime structures and Navy programs
Some S&T unfinished due to short 3-year project duration

26. For More Information Visit the MOB WEB Site: http://mob.nfesc.navy.mil
the Program Office: