Planning revision: 28 October 2026. Status: preliminary; not a released build specification.
Construction starts only after M2 — Reviewed construction package. Design-stage preparation may cover quotations, workshop measurements, sample joints and supplier availability. Cutting production parts, ordering specification-dependent items and permanent assembly require the relevant released drawings and specifications.
The project wiki currently describes a 6.20 m decked plywood/epoxy cutter, 2.28 m beam, 1.15 m draft, 1,490 kg light displacement, 1,970 kg maximum displacement, 520 kg ballast and 25.5 m² sail area. These are concept inputs, not verified as-built values. This plan was prepared from the wiki and work packages; linked CAD files and calculation reports were not inspected through this connector.
M2 is a technical release gate, not evidence of statutory certification.
All quantities are TBD unless explicitly identified as concept values. Do not interpret an empty quantity as zero. Sheet thicknesses, glass weights, fastener sizes and attachment arrangements must come from reviewed design, not generic boatbuilding practice.
| ID | Material or assembly | Unit | Quantity / basis | Required release information |
|---|---|---|---|---|
| B01 | Hull plywood, separated by panel and thickness | sheets, m² | TBD from approved nesting | Grade, species, thickness, sheet size, grain direction, certificates |
| B02 | Deck, cockpit and cabin plywood | sheets, m² | TBD from drawings | Thickness, openings, local reinforcement, sealing details |
| B03 | Bulkheads, floors, webs and internal plywood | sheets, m² | TBD from parts list | Structural versus furniture parts, cutouts and edge details |
| B04 | Structural timber, cleats, stringers and laminations | m, m³ | TBD from section/length schedule | Species, grade, section, moisture limits and joints |
| B05 | Resin and matching hardener | kg | TBD from bonded/coated areas and trials | Selected system, mix method, working/cure conditions, shelf life |
| B06 | Structural fillers and fairing fillers | kg | TBD from joint volumes and fairing estimate | Approved filler by operation; do not interchange functions |
| B07 | Glass cloth and tapes | m², m | TBD from laminate and seam schedule | Fibre type, weight, orientation, widths, overlaps and layer count |
| B08 | Ballast and attachment assembly | assembly, kg | 520 kg concept target; final TBD | Material, geometry, actual mass/CG, bolts/foundation and corrosion protection |
| B09 | Keel, rudder, stock, bearings and steering hardware | sets | TBD from appendage drawings | Loads, materials, tolerances, attachments and service access |
| B10 | Mast, boom, gaff, bowsprit and fittings as selected | sets | TBD from rig drawings | Sections, material, foundations, tangs and rigging interfaces |
| B11 | Standing and running rigging, blocks and cleats | m, pieces | TBD from rigging schedule | Loads, sizes, terminals, routing, reefing and replacement access |
| B12 | Mainsail, staysail and jib | set | One concept sail set, 25.5 m² total; final TBD | Sailmaker-approved dimensions, cloth, reefs, attachments |
| B13 | Deck hardware, chainplates, backing plates and fasteners | pieces, sets | TBD from hardware schedule | Rated loads, material compatibility, bedding and backing details |
| B14 | Hatches, ports, seals, cockpit drains, pumps and hoses | pieces, m | TBD from opening/system plans | Locations, closures, water exclusion, hose routing and access |
| B15 | Auxiliary propulsion and energy/fuel installation, if selected | set | TBD; option decision outstanding | Mounts, ventilation, isolation, cabling/fuel and mass allowance |
| B16 | Electrical, navigation and lighting equipment, if selected | pieces, m | TBD from system schematics | Circuit protection, cable sizes, mounting and access |
| B17 | Coatings, primers, UV-protective finish and underwater finish | L | TBD from area, product coverage and coats | Compatible coating system and preparation/cure requirements |
| B18 | Accommodation, ventilation, anchoring, mooring and safety equipment | sets | TBD from agreed use | Equipment list, secure stowage, masses and access |
| B19 | Jig, strongback, temporary moulds, cradles and transport supports | set | TBD from build/handling method | Geometry, loads, support points and lifting/turning method |
| B20 | Consumables and PPE | lots | TBD by operation | Abrasives, mixing pots, brushes, rollers, release materials, gloves, extraction supplies |
For each line record drawing/revision, net quantity, separately justified waste allowance, order quantity, supplier, quotation date, unit price, tax, freight, lead time, required-on-site stage, mass and receipt inspection. No current supplier prices or availability have been obtained.
Take-off method:
This is a proposed sequence. The selected build orientation, access, ballast attachment and coating system may change the order. Final work instructions must specify dimensions, tolerances, fastening, layups and curing.
| Stage | Proposed work | Release / inspection before continuing |
|---|---|---|
| C0 | Review released documents; freeze BOM, budget, people and build method | M2 complete; correct revisions at workstation |
| C1 | Prepare workshop, jig/strongback, datums and templates; practise representative joints | Workshop/handling readiness; datum and template scale checked |
| C2 | Receive, identify and store materials; nest, mark and cut first approved parts | Material specification and condition checked; first-off part verified |
| C3 | Prepare joints and dry-assemble hull panels/framing in the approved orientation | Symmetry, fairness, reference dimensions, fit and future access signed off |
| C4 | Bond, fillet and reinforce hull and primary structure per drawings | Joint/laminate records; inspect inaccessible areas before closure |
| C5 | Complete external reinforcement/coating as appropriate, then turn hull when approved | Cure and surface inspection; support and turning plan accepted |
| C6 | Install internal structure, appendage foundations, cockpit and system provisions | Foundations, drainage, backing and service access checked before deck closure |
| C7 | Fit deck/cabin and close structure; fair, seal and finish | Closure inspection; protected edges/penetrations; coating compatibility/cure records |
| C8 | Install ballast/appendages and fit out systems and hardware at the designed stage | Attachment inspection; actual masses; controlled tightening and access records |
| C9 | Install rig and sails; set up steering, reefing and controls | Rig load-path/attachment review and dockside functional checks |
| C10 | Weigh and measure completed boat; verify trim, systems and readiness | Resolve deviation from approved mass/load/stability assumptions |
| C11 | Transport, launch, dockside checks and progressive trials | Launch approval; leak checks and trial plan; close findings before expanded use |
No lifting points, attachment torques, laminate schedules or adhesive recipes are inferred here. The designer, selected product documentation and competent handling contractor must supply them.
| Function | Required capability | Own / hire / outsource decision |
|---|---|---|
| Lofting and measurement | Released CAD/print access, calibrated tape/rules, straightedges, squares, levels or laser, battens, templates and labelled datums | Verify print/DXF scale with reference dimensions |
| Cutting and shaping | Suitable saws, supported cutting bench, router/jigs, planes, drills and bits; CNC cutting if selected | Match equipment and extraction to approved materials |
| Assembly | Rigid strongback/jig, trestles, clamps, temporary fixings, cradles and access platforms | Size and count after build method is chosen |
| Bonding and laminating | Manufacturer-approved metering/mixing equipment, pots, spreaders, filleting tools, brushes/rollers and clean work surfaces | Follow selected system instructions; no generic ratios |
| Finishing | Sanders, longboards, effective dust extraction and compatible coating application equipment | Separate dusty operations from bonding/coating |
| Environment and protection | Temperature/humidity monitoring, suitable ventilation, lighting, clean dry storage, product-specific PPE and waste handling | Use selected product data sheets and workshop assessment |
| Fitting and testing | Appropriate torque tools, basic electrical test equipment if needed, inspection lighting and weighing capability | Calibrate or hire where required |
| Handling and transport | Rated lifting/turning equipment, approved slings/supports, adequate transport and launch service | Use a competent provider with a boat-specific handling plan |
Vacuum bagging, welding, casting and spray finishing are not assumed necessities. Decide whether any are required and outsource specialist work where appropriate.
Keep the original 16-week design sequence as an indicative relative plan, not a calendar commitment. Construction durations and dates remain unestimated until labour availability, workshop, budget, build method and supplier lead times are known.
Before M2: prepare quotations, workshop survey, representative non-production samples and logistics options.
After M2: C0/C1 → C2 → C3/C4 → C5/C6 → C7/C8 → C9 → C10 → C11. Some operations may overlap only after the build method and access sequence are reviewed.
Dependencies are recorded in task descriptions. The current connector cannot set formal predecessor links, task hierarchy, assignees or dates; these must be entered in OpenProject when agreed.
Maintain a revision/drawing index, part labels, material/batch register, bond/laminate and environmental log, inspection photos before closure, actual component mass register, change log and defects list. Reassess mass, trim and stability implications of substitutions or added equipment before accepting them.
Commissioning must cover relevant watertight closures, leaks, cockpit drainage, steering travel, rig attachments, reefing/control operation, anchoring and selected electrical/propulsion systems. Confirm the completed boat matches the approved load model; determine with the reviewer what as-built stability verification is required. Plan progressive dockside and sailing trials with defined conditions, personnel, abort criteria and recorded findings. A successful first launch alone does not close the project.
Cotre Carantec 62 is a preliminary concept for a small decked plywood-and-epoxy cutter inspired by traditional boats from northern Finistère. It is a modern interpretation, not a historical replica and not yet a construction-ready design.
Principal dimensions and design figures:
The preliminary maximum-load model gives KG = 0.324 m, initial GM = 1.34 m and maximum GZ about 0.63 m near 70°. These values must be revalidated after modelling the cockpit, openings, downflooding, final structure, equipment and realistic load cases.
The CAD design is full-size at 1:1 scale. Main model coordinates are in metres. The developed-panel DXF is expressed in millimetres. PNG and SVG exports are presentation drawings and must not be used directly as cutting templates.
Preliminary cutter sail plan:
This balance is an initial geometric estimate. The sailmaker and naval architect must refine sail shape, reefing arrangements, mast and rig loads, weather helm, keel and rudder geometry.
| Phase | Target period | Main outcome |
|---|---|---|
| WP1 — Design basis | Weeks 1–2 | Requirements and assumptions frozen |
| WP2 — Stability and flooding | Weeks 2–5 | Validated hydrostatics, openings and downflooding model |
| WP3 — Rig, appendages and mass | Weeks 4–7 | Refined sail balance, appendages and weight model |
| WP4 — Structure and drawings | Weeks 7–12 | Preliminary scantlings and coordinated construction package |
| WP5 — Review and release | Weeks 12–16 | External technical review and controlled design release |
Added 28 October 2026. The figures above remain preliminary. This review covered the project wiki and work packages, not the linked calculation reports, CAD assemblies or DXF files. A task marked New is not proof that no work has occurred; it means completion evidence has not been recorded here. The explanations below interpret the recorded concept and identify what must be demonstrated.
The documented concept combines a small decked hull, plywood/epoxy construction and a traditional cutter appearance. The deck/cockpit arrangement, panel shapes, ballast and rig must be developed together: moving a bulkhead or opening can alter structural support, access, weight and flooding behaviour.
Developed plywood panels are intended to translate the three-dimensional hull into cuttable flat shapes. A DXF export alone does not demonstrate that the panels will form the intended hull without unacceptable distortion. Fairness, developability, grain direction, joint positions, assembly tolerances and a representative fit check remain part of #52. The final drawings must state whether and where glass reinforcement is structural, protective or both.
The structure must provide continuous load paths: mast compression and rig tension into suitable foundations and hull structure; ballast/keel loads into floors and adjacent structure; rudder loads through stock/bearings and attachments; deck fitting loads through backing and supports. Plywood thickness alone cannot define these load paths. Member sizes, spans, joints, laminates, fastening and local reinforcement remain design outputs of #51.
Displacement is the mass of water displaced by the floating boat, equal to total boat mass in equilibrium. The proposed light and maximum displacements differ by 480 kg (1,970 − 1,490 kg). This is a provisional loading allowance, not a demonstrated passenger capacity. The definition of light condition must first establish what fixed equipment, rig, ballast, propulsion and fluids are already included. People, stores and loose equipment must then be added without double counting.
The 520 kg ballast figure is a target. Its final mass, vertical/longitudinal position and attachment influence stability, trim, structural loads and handling. The mass model must include resin, glass, coatings, hardware, rig, sails, systems and realistic uncertainty as well as plywood and timber. Added equipment high in the boat can raise the centre of gravity; component weights must be reconciled with the material take-off.
KG is the height of the centre of gravity above the model's vertical reference. Its reported 0.324 m is only interpretable once that datum is documented. GM describes initial stability near upright. A preliminary GM of 1.34 m does not establish safety at larger heel angles or in waves.
GZ is the horizontal righting lever at a given heel angle. The reported maximum of about 0.63 m near 70° is one point on a preliminary curve; assessment requires the complete curve, load condition and flooding limits. A positive calculated lever is useful only while the assumed watertight boundary remains valid. Openings, cockpit water, crew movement and actual equipment/ballast positions can change the result.
The remaining stability study must therefore model openings and downflooding, cockpit drainage, relevant load cases and sensitivities, and the applicable buoyancy/recovery criteria. Intended design category and operating limits remain unvalidated until the reviewer accepts the relevant evidence. Nominal overall length is not automatically the hull-length measurement used to choose a standard.
A cutter divides the headsail area between the staysail and jib; together with the gaff mainsail this gives several possible sail combinations. The proposed areas total 25.5 m², but the final reefing and sail-handling arrangements remain to be designed.
The centre of effort (CE) is an estimated resultant location for sail forces; the centre of lateral resistance (CLR) is an estimate for the underwater lateral plane. The recorded longitudinal separation is 0.552 m, or about 9.94% of the 5.55 m waterline length. Its meaning depends on the CAD axis and sign convention, which must be stated before calling it forward or aft.
Geometric separation alone cannot establish helm balance. Sail shape, heel, reefed combinations, hull form and keel/rudder behaviour affect the actual forces. The sailmaker/reviewer must coordinate mast position, sail geometry, appendages, steering and rig attachment loads, then define what commissioning trials will verify.
The day-sailing and two-person overnight intentions need dimensioned cockpit, accommodation, ventilation, stowage, movement and maintenance-access checks. Auxiliary propulsion and its energy/fuel system, electrics, pumping/drainage and navigation equipment are not specified in this wiki. Decisions are required before freezing weights, openings, reinforcement and the BOM.
The documented rationale is still incomplete: record why the selected hull dimensions, draft, ballast, rig and layout best meet the agreed use, along with alternatives considered and their cost, transport, handling and sailing tradeoffs. Do not present a plausible rationale as an established design decision without owner/designer confirmation.
All entries below remain open in project tracking at this review. Existing task descriptions have been expanded rather than duplicated.
| Task | Remaining output / completion evidence |
|---|---|
| WP1.1 — Requirements | Approved use/load assumptions, coordinate/unit conventions, standards route and versioned baseline |
| WP1.2 — Layout and access | Dimensioned general arrangement and ergonomics/maintenance-access checks |
| WP2.1 — Stability | Reproducible hydrostatics/GZ, openings/drainage/downflooding assessment and accepted load limits |
| WP3.1 — Rig and appendages | Coordinated rig/sail/reefing, keel/rudder and load/interface drawings |
| WP3.2 — Mass and trim | Traceable mass/CG register, load cases, uncertainty and BOM reconciliation |
| WP4.1 — Structure | Reviewed scantlings, load paths and joint/laminate/fastener details |
| WP4.2 — Panels and drawings | Checked CAD/DXF revisions, developed panels, nesting, datums/tolerances and coordinated assembly package |
| WP4.3 — Systems | Equipment decisions, schematics, routing, penetrations and installation/test criteria |
| WP5.2 — Mock-ups and joints | Representative fit/access/joint evidence with findings resolved in drawings |
| WP5.1 — Technical review | Closed review findings and controlled construction release |
| M2 — Reviewed construction package | Accepted design evidence and consistent released calculations, drawings, specifications and build/inspection instructions |
Suggested progression: requirements/layout → stability/mass/rig iterations → structure/systems → coordinated drawings and mock-ups → review → M2. Revisit earlier calculations whenever an interface or mass changes.
The construction preparation and build plan now contains:
Trackable preparation and construction work:
Quotations and workshop planning can be prepared during design. Production cutting and permanent construction require accepted M2 and construction readiness. Quantities, prices, labour estimates and calendar dates remain TBD, pending released design, supplier quotations and owner resource decisions. Dependencies are described in the tasks; formal predecessor links, hierarchy, assignees and dates could not be set through this connector.
On 28 October 2026, ISO's catalogue lists ISO 12217-2:2022 as published with a revision under development, and ISO 12215-5:2019 with a March 2024 corrected version. Reconfirm applicable editions with the reviewer at release. Catalogue summaries establish scope, not compliance or a substitute for the full standards.
The current files are suitable for concept development and technical review. Panel patterns, plywood thicknesses, structural details and stability results must be checked against the applicable standards and approved by a qualified naval architect before material is cut or construction begins.
The parametric hull design notebook is now available with an attached, executed .ipynb file. It explains input selection and hypotheses, generates an editable educational hard-chine candidate, calculates upright flotation/initial stability, compares load cases and shape variants, and includes optional online data imports with provenance. Numerical checks passed. Live imports remain untested and disabled by default. The model is independent of the existing FreeCAD hull and does not validate its GM/GZ figures, develop panels or release construction. See the notebook page for reconciliation steps against #47, #48, #50 and #52.
Revision 0.1 — 31 October 2026.
A runnable Python Jupyter notebook accompanies this page. It explains the recorded Carantec targets, how to choose inputs, which hypotheses are provisional, and how to iterate a candidate hull. Download the attached .ipynb, open it in JupyterLab/Notebook, edit the parameter cells and run all cells. Dependencies: Python 3.10+, numpy, pandas, scipy, matplotlib.
The core offline calculation cells were executed successfully before upload. The maximum-load candidate waterline is about 0.4704 m above this notebook's hull-bottom datum; BM changes by less than 0.01% between 201 and 401 stations. These are results for an educational candidate, not verified results for the existing FreeCAD hull. Optional live data imports were not executed in this environment and are disabled by default; no downloaded dataset or live-weather results are claimed.
The linked CAD, original reports and DXF were not read through this connector. Shape controls and component CG allocations are clearly labelled hypotheses. Hull buoyancy excludes appendages; upright hydrostatics assume zero trim. The trim calculation is only a linear indication. No full GZ/downflooding analysis, scantlings, panel development or speed prediction is supplied. Existing wiki GM/GZ figures are not validated by this independent model. The notebook frame must be reconciled with CAD before comparing CG values.
Confirm inputs in #47, replace the mass placeholders in #50, reconcile geometry in #52, and extend validated stability in #48. The notebook supports investigation; it does not close these tasks or release construction at M2.
Use model/provider attribution and current source terms. Reanalysis and forecasts do not establish design extremes, navigation advice or structural loads.