Appendix · 60×60
08 Appendix
Sources, series and open registers
The material that keeps the claim auditable: the risk register, the deliverables that would prove design maturity, the reported biomass series and the reconciliation of source versions.
Principal project risks
| Risk | Potential consequence | Priority control and owner |
|---|---|---|
| Diversion below target | Limited protection and failure of commercial expectations | Validate transport and interaction assumptions; oceanography and pilot lead |
| Biomass accumulates locally | Higher loads, poor water quality, interrupted service | Define retention limits and clearing method; operations and environment |
| Downstream or return impacts | Redistribution of exposure to other areas | Model fate and monitor receiving pathways; environmental lead |
| Mooring or foundation failure | Loss of position, drifting assets, navigation hazard | Site investigation, coupled analysis and failure cases; mooring engineer |
| Pipe or connection fatigue | Progressive damage, leakage, loss of availability | Material qualification, fatigue design and inspection; structural engineer |
| Loss of buoyancy | Submergence, changed loads, difficult recovery | Compartment design, damage assessment and alarms; system engineer |
| Extreme weather | Asset damage, long outages, unsafe marine work | Validated survival and recovery plan; marine operations lead |
| Navigation interaction | Collision, entanglement, restricted access | Traffic study, approved gaps and marking; navigation coordinator |
| Permitting delay | Redesign, delayed installation, sunk procurement cost | Early scoping and consent dependency register; approvals lead |
| Supplier failure | Defective components, delay, additional vessel cost | Qualification, first article tests, transport planning; procurement |
| Unclear commercial scope | Budget overrun and disputes over maintenance or performance | Quantity based estimate and explicit scope matrix; commercial lead |
| Insufficient operating resources | Deferred maintenance, lost monitoring, low availability | Funded lifecycle plan and service contracts; sponsor and operator |
| Unreliable data or control | Late response, misleading performance conclusions | Calibration, redundancy, quality flags, audit trail; monitoring lead |
A qualitative starting point. Likelihood, consequence, residual risk and quantitative allowances must be assessed by the responsible team once the design basis and field data exist.
Each material risk needs a named owner, a target date, the evidence required to close it and a closure authority. A mitigation action is not proof that the mitigation worked.
Reported biomass series, 2010–2027
Source reported estimate. Projection from 2027 onward is not validated.
Values reproduced from the source presentation, attributed there to Esteban Jesús Amaro Mauricio, CEMAS. The 2027 value is a projection. These are source reported estimates, not independently validated measurements.
Methodological questions to resolve
- Establish whether each annual number is a peak stock, a mean stock, an integrated production estimate or another statistic. Repeated observations of the same floating material are not additional annual biomass.
- Review cross sensor calibration, detection thresholds, geographic masks, cloud treatment, wet mass conversion and uncertainty between the MODIS series for 2010–2017 and the Sentinel based estimates for 2018–2026.
- Specify the observation window for 2026 and the forecast model, training period and uncertainty range for 2027. No extrapolated growth curve is used here as a structural design load.
Deliverables that would demonstrate maturity
| Deliverable | Minimum content | Acceptance evidence |
|---|---|---|
| Design basis | Requirements, environment, service life, codes, assumptions | Approved inputs, closed critical assumptions |
| Metocean report | Measurements, historical context, variability, design conditions | Quality controlled data, justified statistics |
| Bathymetry and route | Depths, datums, uncertainty, constraints | Checked georeferenced files, coverage |
| Seabed and habitat | Geology, sediment, geotechnics, biological features | Sampling records, suitability for anchor design |
| Water quality baseline | Methods, locations, results, interpretation | Laboratory records, reproducible dataset |
| Remote sensing package | Images, processing, masks, conversion, uncertainty | Field validation, versioned processing |
| Transport model | Hydrodynamics, motion, barrier response, scenarios | Calibration, independent evaluation, sensitivity |
| Structural and mooring | Loads, buoyancy, strength, fatigue, stability, foundations | Checked calculations, independent review |
| Construction drawings | Geometry, materials, interfaces, tolerances | Approved revision, coordinated interfaces |
| Marine procedures | Fabrication, launch, tow, installation, temporary works | Qualified method, vessel capability, weather limits |
| Operations manuals | Operating states, alarms, inspections, repairs, spares | Operator review, training, demonstration |
| Bill of quantities | Measured quantities, rates, scope, exclusions, allowances | Traceability to drawings and quotations |
| Environmental assessment | Alternatives, impacts, mitigation, monitoring | Review decisions, incorporated conditions |
| Handover record | As built, tests, assets, warranties, open items | Complete indexed dossier, accepted handover |
Document delivery is not technical acceptance. Review confirms that calculations, drawings, quantities, procedures and operating limits describe the same configuration.
Glossary and conventions
- GBO 60×60
- Concept with nominal 60 km length and 60 degree orientation.
- Holopelagic sargassum
- Sargassum that spends its life floating in the open ocean.
- Diversion efficiency
- Fraction of eligible incoming biomass guided through a defined exit boundary.
- Coastal arrival reduction
- Change in biomass reaching a destination over a defined period.
- HDPE
- High density polyethylene, the proposed pipe material family.
- SDR
- Standard dimension ratio: nominal outside diameter divided by nominal wall thickness.
- Freeboard and draft
- Height above the water surface and depth below it.
- Reserve buoyancy
- Buoyant capacity available beyond the specified loaded condition.
- Metocean
- Combined meteorological and oceanographic design conditions.
- Bathymetry
- Measurement and mapping of underwater depth and seabed form.
- Mooring excursion
- Movement of a restrained component away from its reference position.
- Station keeping
- Maintaining position and orientation using moorings, propulsion or both.
- RTK and GPS
- Real time kinematic positioning and the Global Positioning System.
- ROV and USV
- Remotely operated underwater vehicle and uncrewed surface vessel.
- MIA
- Manifestación de Impacto Ambiental, an environmental impact submission in Mexico.
- FAT and commissioning
- Factory acceptance testing and verification of installed functions.
- CAPEX and OPEX
- Capital expenditure and recurring operating expenditure.
- Mtm and wet mass
- Million metric tonnes and mass under a defined drainage convention.
Unit conventions
One metric tonne equals 1,000 kg. One kilometre equals 1,000 m. One inch equals 0.0254 m: 32 inches = 0.8128 m, 40 inches = 1.016 m, 52 inches = 1.3208 m, 60 inches = 1.524 m. The letter M after a currency denotes millions. Bearings are true north with a stated coordinate reference system once confirmed. Preserve whether a biomass value is wet or dry, stock or rate, and the area and period it applies to. Proposed, estimated, target and measured are different evidence states.
Source reconciliation
The conference, planning meeting and presentation describe successive or alternative versions. The explicit 60 km presentation configuration is the reference here; differences are retained until closed by an engineering or commercial decision.
| Topic | Source history | Treatment in this dossier |
|---|---|---|
| Total length | Conference 60 km; meeting other lengths including about 70 km; presentation 60 km | Use 60 km; other lengths excluded from base investment |
| Segment arrangement | Meeting contains an ambiguous spoken unit; presentation states six 10 km segments | Use six 10 km segments; obtain a coordinated layout drawing |
| Orientation | Conference 60 degrees from north; presentation toward the northeast | Nominal 60 degrees; confirm true north and operating range |
| Pipe and float diameter | Conference 32–52 inch pipe; illustration 40 inch; text 60 inch floats | Treat as distinct components or alternatives; no final pipe diameter |
| Fabrication length | Conference about 150 m; meeting proposes 120 m | Use 120 m for illustrative logistics only; module length open |
| Mooring architecture | Earlier deadweights and deep water lines; meeting adds cylindrical support | Select one integrated architecture after survey and analysis |
| Unit cost | Meeting about USD 1.5444 M/km; presentation USD 1.5244 M/km | Use presentation value; reconcile the USD 1.2 M difference |
| Operating cost coverage | Meeting mentions operation and maintenance; presentation describes installed cost | Do not assume service duration or lifecycle coverage |
| Delivery timing | Meeting roughly 3 months technical and 5 months commercial; presentation about 17 months | Separate engineering objectives from physical delivery |
| Diversion and benefit | Channel share above 90 percent and diversion target above 90 percent both reported | Keep as separate metrics; neither sets beach protection |
| Design maturity | Meeting describes earlier engineering as 80–90 percent complete | Require documents and reassessment; no completion percentage adopted |
| Biomass series | Annual values through 2027 with a fitted growth curve | Preserve values, identify forecast, require methodological review |
Source record
Project specific facts are attributed to the supplied presentation, planning discussion and conference. Publications provide technical or regulatory background only.
- [1] GBO 60×60 presentation 2026. User supplied PDF, 12 pages. Configuration pp. 5–6; studies pp. 7–8; programme p. 9; investment p. 11; biomass series p. 4.
- [2] Project barrier planning meeting. Plaud record, 4 November 2026, approximately 39 minutes. Technical references use elapsed recording time.
- [3] First Sargassum Forum conference, Dr. Esteban Jesús Amaro Mauricio. Supplied audio with a reviewed working transcript.
- [4] Plastics Pipe Institute, Handbook of PE Pipe, chapter 10, Marine Installations. Background only.
- [5] Copernicus Sentinel 2 mission documentation. Spectral bands at 10, 20 and 60 m.
- [6] Copernicus Sentinel 3 OLCI instrument documentation. Approximately 300 m full resolution sampling.
- [7] SEMARNAT environmental impact assessment content requirements.
- [8] United States Coast Guard floating offshore facility types. Terminology only.
- [9] IALA Recommendation R0139, marking of man made offshore structures.
Dossier dated 6 November 2026
Source links are provided for traceability. Project approvals and contractual commitments require their own records.