Navigator Walkthrough - How to Use This Site
Rev: v3.0 · Updated: 2026-05-29
Navigator of Lupo Di Mare — what to read, when, and what to do with it, from T-10 to the finish.
TL;DR
- The spine is one command:
.venv/bin/python scripts/daily_brief.pyruns fetch → classify → match → brief and writes a dated brief todata/daily-brief/. Run it daily from T-10. It automates the GFS/ECMWF/ICON pull, the W-* pattern call, and the analog ranking — see Pre-Race Data Workflow. - What stays manual is the judgement layer: Gulf Stream imagery (RTOFS/SST/AVISO), Expedition routing runs, and the per-gate decisions below.
- Protect the three gates (Stream-entry sail, current confirmation, model agreement) and pull the right onboard card for each phase.
- Rule line: all AI/analog analysis is pre-race only — no shore routing advice once the gun fires (RRS 41 modification).
Quick reference — what to open when
| Situation | Open this |
|---|---|
| Just assigned as navigator | Crew Orientation, then Navigator Playbook |
| Daily forecast pull (T-10 on) | Run daily_brief.py; method in Forecast Analog Matcher |
| Classifying the pattern by hand | Weather Analog Framework |
| Pattern → tactic shortlist | Model → Tactic Synthesis |
| Detailed tactic profiles | Routing Tactic Catalog |
| Stream analysis (T-7→T-5) | Gulf Stream Framework + Crossing Strategies |
| Cold-core ring confirmation | CCR Guide |
| Warm-core eddy concern | WCE Guide |
| Pre-race crew brief | Crew Orientation + all 10 onboard cards |
| Approaching the Stream | Card 03, then Card 04 |
| Squall developing | Card 09 |
| Something unexpected | Navigator Playbook → Failure modes |
Three gates to protect
| Gate | Where | Rule |
|---|---|---|
| 1 — Stream-entry sail | Card 03, T-2h before north wall | Entry sail locked 2 h before the SST gradient — fix it in the 50-nm approach window. A peel inside the Stream is skipper-cleared, not a watch default. |
| 2 — Current confirmation | Card 04, at the north wall | Do not commit T-CCR or T-ME on RTOFS-only data. SST + altimetry must confirm. If not: default T-RH, brief Skipper. |
| 3 — Model agreement | Before any major routing call | GFS vs ECMWF arrival Δ >6 h → HIGH UNCERTAINTY. No high-commitment call (meander entry, ring exploit) until they converge. |
The one-command spine
.venv/bin/python scripts/daily_brief.py # fetch → classify → match → brief
Writes a dated brief to data/daily-brief/. The steps below that used to say "pull GFS/ECMWF/ICON, classify the pattern, rank the analog" are now this command — the brief's trend block tracks model agreement day-over-day (it replaced the old hand-kept comparison log). Read the Pre-Race Data Workflow for the full day-by-day procedure; this page is the navigator's reading/decision overlay on top of it.
Pre-Race: T-10 (Jun 9) → T-0 (Jun 19)
| Gate | Run / read | Decision output |
|---|---|---|
| T-14 (Jun 5) — foundation | Crew Orientation, Navigator Playbook, Polars (plan at S3 / 10% degradation), Sail Inventory | Solution space defined before Expedition opens |
| T-10 (Jun 9) — baseline | daily_brief.py; cross-read Weather Analog Framework |
Pattern classified; 2–3 analog years; long-range signal only — do not commit |
| T-7 (Jun 12) — hypotheses | Re-run brief; Model → Tactic Synthesis (Pattern Matrix → Model filter → Stream filter → Expedition). Base meta-tactic is T-CL. | 3–5 routing hypotheses; preferred strategy at S3 |
| T-5 (Jun 14) — Stream lock | Gulf Stream Framework + Crossing Strategies; RTOFS+SST+AVISO | North wall, CCR/WCE, entry latitude + crossing-sail commit |
| T-3 (Jun 16) — critical gate | Re-run brief; compute GFS vs ECMWF arrival Δ | Δ ≤6h → proceed; Δ >6h → HIGH UNCERTAINTY, brief Skipper, dual contingencies. Crossing window locked |
| T-48 (Jun 17) — crew brief | Everyone present | Pattern, first 24 h, Stream plan, 30/20/10 nm squall protocol, sail plan; hand out all 10 cards |
| T-24 (Jun 18) — final | Last cycle; finalize Expedition waypoints | Waypoints to St. David's Head locked; nav-computer checklist (nav/PRE_RACE_CHECKLIST.md); watch/sleep plan set |
| T-0 (Jun 19) — start | Card 01 | Crew briefed on first 12 h; routing in Expedition; navigator rested |
Stream-lock detail (T-5)
- North wall: SST + RTOFS together. Agree → plan entry directly. Disagree → note uncertain, plan a conservative default.
- CCR: SST + RTOFS + altimetry — all three must agree before routing through it. RTOFS-only is not actionable (CCR Guide).
- WCE in path (31–34°N): default avoid; an adverse limb can cost 20+ nm (WCE Guide).
- Meander exploit (T-ME): SST + RTOFS together, with a pre-calculated exit latitude. Never enter without knowing where to exit.
Crew-brief detail (T-48)
Cover: analog + fleet-typical behavior + Lupo's strategy; first-night conditions; Stream position and plan; squall protocol (each crew member states the action at every threshold without looking); sail plan; and confirm every crew member has read all 10 onboard cards before departure.
Onboard: Start to Finish
| Card | Phase | Elapsed (typ.) | Key navigator decision |
|---|---|---|---|
| 01 | Start to Block Island | 0–12h | First-night conditions, tidal current, first decision point |
| 02 | Offshore approach | 12–30h | Second night, offshore wind trend, sleep schedule |
| 03 | Pre-Gulf Stream | 20–35h | Stream-entry sail commit, crew brief, role assignments |
| 04 | Gulf Stream entry | ~35–40h | Current confirmation, routing commit, squall protocol active |
| 05 | Inside Gulf Stream | 35–50h | Radar cadence, sail freeze, current observation |
| 06 | Gulf Stream exit | 45–55h | Exit confirmation, post-Stream wind transition |
| 07 | Mid-ocean transition | 55–70h | Tactical reset, model update, crew rest |
| 08 | Bermuda approach | 70–85h | Final 150 nm, approach angle, WCE avoidance |
| 09 | Squall & frontal response | Any | 30/20/10 nm thresholds, all-hands protocol |
| 10 | Tactical scenarios | Any | Sail selection, reef timing, bash-vs-deflect |
Cards 03 and 04 are the highest-stakes. If anything from the pre-race plan changed, work through their contingency sections before crossing the north wall.
Navigator's continuous loop (watch-on)
- GRIB/RTOFS update on the briefed schedule — not "when interesting."
- Current cross-check: GPS SOG − boat log = experienced current; compare to RTOFS; flag persistent divergence to Skipper.
- Wind cross-check: instrument TWS/TWD vs forecast; flag persistent divergence.
- T-CL gate check: any deviation needs a named data trigger, a counted maneuver cost, and Skipper concurrence.
- Watch Captain at handoff: route, next decision point, current trend, forecast change.
- Before sleeping: brief Skipper on the next forecast inflection so the watch can act without waking you.
Post-Race: Debrief
After finish, complete the Debrief Template — actual vs pre-race route, which analog held, Stream-feature accuracy (SST/altimetry), and what to do differently.
Sources
- Pipeline —
scripts/daily_brief.py(fetch → classify → match → brief); day-by-day procedure in Pre-Race Data Workflow; method in Forecast Analog Matcher. - Pattern → tactic — Weather Analog Framework, Model → Tactic Synthesis, Routing Tactic Catalog.
- Stream analysis — Gulf Stream Framework (refreshed by
scripts/gulfstream_monitor/). - Onboard execution — Onboard Cards 01–10; roles in the Navigator Playbook.
PRE-RACE RESEARCH — not race-period routing advice. Updated 2026-05-29.