Routing Tactic Catalog - Newport to Bermuda
Rev: v2.1 · Updated: 2026-05-29
TL;DR
- Lupo's default is T-CL — Conservative Lane overlays everything else. Every winning route in the database includes T-CL.
- Two-source rule: SST + altimetry must confirm before committing T-CF / T-CCR / T-ME. RTOFS-only = H-HR; do not commit.
- T-CL is incompatible with T-CCR (ring exploit requires multiple peels).
- T-ME is the highest-upside pairing with T-CL — pre-commit the exit latitude at T-1; exit is harder than entry.
- 8 tactics still tag-only (T-WR, T-ER, T-NW, T-RR, T-RL, T-RR2, T-LA, T-FR) — historical reference, not Phase-1 decision tools.
Lupo applicability — quick decision matrix
| Tactic | Name | Lupo applicability | Risk | Two-source required? |
|---|---|---|---|---|
| T-CL | Conservative Lane (default) | HIGH | LOW | n/a |
| T-RH | Rhumb line hold | HIGH | LOW | n/a |
| T-PF | Pressure first | MEDIUM-HIGH | MEDIUM | n/a |
| T-ME | Meander exploit + exit | HIGH if confirmed | MEDIUM | YES |
| T-CF | Current first | MEDIUM | HIGH model-only / MED-LOW confirmed | YES |
| T-CCR | Cold core ring exploit | CONDITIONAL | HIGH | YES (all 3: SST + altim + RTOFS) |
| T-EC | Early crossing | MEDIUM | MEDIUM | — |
| T-LC | Late crossing | LOW-MEDIUM | MEDIUM | — |
| T-WCE | Warm core eddy avoid | Always check | LOW (avoidance) | — |
| T-WR / T-ER / T-NW / T-RR / T-RL / T-RR2 / T-LA / T-FR | (tag-only — see Tactic Tags) | — | — | — |
Routing labels
H-HR — high-risk / high-reward. Feature forecast but not confirmed by two independent data sources (e.g., RTOFS-only). Lupo does NOT commit to H-HR routing; default to T-RH or T-PF until two-source confirmation.
Tactic Tags
| Tag | Name | One-Line Description |
|---|---|---|
| T-RH | Rhumb line hold | Stay on or near great circle; accept whatever current encountered |
| T-WR | West route | Go west of rhumb to avoid adverse Stream or find favorable clockwise meander |
| T-ER | East route | Go east of rhumb to find better pressure, avoid westward eddy, or exploit Stream bend |
| T-PF | Pressure first | Optimize for wind strength and angle; current secondary |
| T-CF | Current first | Route aggressively toward favorable Stream; accept wind compromise |
| T-EC | Early crossing | Cross Gulf Stream early (north of rhumb crossing latitude) |
| T-LC | Late crossing | Cross Gulf Stream late (south of typical crossing latitude) |
| T-NW | North wall hug | Follow north wall close to maximize current benefit |
| T-CCR | Cold core ring exploit | Route through/around CCR for favorable eddy flow |
| T-WCE | Warm core eddy avoid | Explicit routing to dodge WCE south of main Stream |
| T-RR | Ridge ride | Align with Bermuda High ridge axis for consistent reaching angle |
| T-RL | Ridge left (west) | Go left (west) side of ridge for stronger pressure |
| T-RR2 | Ridge right (east) | Go right (east) side of ridge for better angle to Bermuda |
| T-LA | Light air gamble | Aggressive routing through light zone banking on pressure on other side |
| T-FR | Front timing | Time fleet position to be on favorable side of a front |
| T-CL | Conservative lane | Minimize maneuvers; maintain safe, manageable course; accept slightly longer route |
| T-ME | Meander exploit + exit | Identify and ride favorable Stream meander; commit to pre-calculated exit latitude |
Tactic Interaction Matrix (reference — the load-bearing interactions are already called out in the profiles below)
| Tactic A | Tactic B | Compatibility |
|---|---|---|
| T-CL | T-CCR | Incompatible — ring exploit typically requires multiple peels |
| T-CL | T-ME | Partially compatible — enter meander, exit conservatively at pre-planned latitude |
| T-CF | T-EC | Compatible — current-first often means earlier crossing |
| T-CCR | T-RH | Incompatible — ring exploit requires significant off-rhumb routing |
| T-WCE | T-ER | Often incompatible — east route may increase WCE exposure |
| T-PF | T-EC | Sometimes incompatible — pressure first may mean holding south longer |
| T-FR | T-PF | Often synergistic |
| T-RR | T-PF | Synergistic |
| T-ME | T-CF | Synergistic |
| T-ME | T-CCR | Distinguish carefully — confirm which feature is present before committing |
Tactic Profiles
T-RH — Rhumb Line Hold
When it works: Gulf Stream normal position (~37.5–38.5°N on rhumb); no CCR on rhumb; wind from W–NW; models agree within 6h on rhumb elapsed time.
When it fails: North wall shifts north → >2 kts adverse for 60+ nm; front cuts fleet and lateral boats capitalize; CCR NE of rhumb creates exploitable shortcut.
Lupo applicability: HIGH — medium-displacement offshore racer doesn't pay heavy penalty for staying near rhumb. Conserves crew energy and avoids maneuver costs. Use as baseline comparison for all other strategies.
Risk: LOW if Gulf Stream normal. Rises to HIGH if significant CCR present and competitors exploit it.
T-CF — Current First
When it works: Clearly defined current feature within 30–50 nm of rhumb; adds 1.5–3 kts favorable; routing software shows >8–10h savings vs rhumb at S3.
When it fails: Ring position forecast but not verified by SST or altimetry; ring smaller or weaker than predicted; wind angle post-exit creates long beat to Bermuda.
Critical: Do NOT route to exploit current that has not been confirmed by SST imagery AND altimetry/SSH anomaly. RTOFS alone = H-HR. Require independent confirmation before committing.
Lupo applicability: MEDIUM — evaluate against S3 degradation.
Risk: HIGH if model-only. MEDIUM-LOW if SST + altimetry confirmed.
T-PF — Pressure First
When it works: Models show significant pressure differential (4+ kts) for non-rhumb track; Stream crossing benign regardless of approach; reaching angles dominate and pressure band stable for 24+ hours.
When it fails: Pressure advantage evaporates in Day 3 model evolution; pressure route adds 40+ nm and wind advantage doesn't compensate.
Lupo applicability: MEDIUM-HIGH — pressure matters most in light conditions where slight wind differences compound.
Risk: MEDIUM — depends on model agreement.
T-EC — Early Gulf Stream Crossing
When it works: North wall shifted north (~38.5–39°N); post-frontal NW makes cross-Stream direction favorable; routing software confirms net time saving.
Typical elapsed: Crossing latitude ~36.5–38°N; duration 8–14h for 40–50 ft boat at 8–10 kts.
Lupo applicability: MEDIUM — viable when NW post-front conditions forecast to hold for the crossing window.
T-LC — Late Gulf Stream Crossing
When it works: CCR available to NE; SW wind makes north wall hug a favorable reaching angle; late crossing exits into favorable SE fetch.
Lupo applicability: LOW-MEDIUM — adds distance; requires clear current feature to justify.
T-CCR — Cold Core Ring Exploit (highest-reward / highest-risk)
What a CCR is: Separated cold-water ring from the north wall. Counter-clockwise flow. Eastern side: adverse (southward). Western side: favorable (northward) — the routing target.
Identification: SST cold core (5–14°F cooler); altimetry SSH LOW (−10 to −20 cm vs background); RTOFS counter-rotation cell.
Routing: Target western limb (1.0–2.5 kts favorable). Eastern limb or interior = adverse; boats that go inside or east of a CCR lose badly.
Lupo applicability — CONDITIONAL. ALL four conditions required: 1. CCR confirmed by SST + altimetry (not RTOFS-only) 2. Western limb within 40 nm of rhumb (otherwise distance cancels gain) 3. Routing software at S3 shows >6h net saving after maneuver-cost adjustment 4. Wind supports the required routing angles
If ANY condition not met: default to T-RH or T-PF.
T-ME — Stream Meander Exploit and Exit
Key difference from T-CCR: A meander is a bend in the main Stream — connected, not detached. More position-reliable than a CCR, but requires planning the exit before committing to the entry.
Historical precedent: 2024. Up to 5 kts NE current. "We needed to figure out when to get off the ride." Carina won by exploiting it and exiting at the right latitude.
Identification: SST shows Stream axis bends south of climatological position creating NE-flowing eastern limb; RTOFS shows NE flow of 2+ kts in limb; unlike CCR: no isolated SSH LOW (feature is connected to main Stream).
Entry: Route to enter the NE-flowing limb; enter where current is 2+ kts favorable.
Exit decision (equally important): 1. Pre-calculate: at what latitude does VMG to Bermuda from inside meander match the rhumb-line boat's VMG? 2. When meander set is carrying you east of rhumb and angle to Bermuda is deteriorating: exit now 3. Exit trigger rule: when the bearing to Bermuda from your current position has rotated more than 15° from the pre-planned meander-exit bearing (computed and written on the route card at T-1 — not the rhumb heading and not the meander-entry bearing), evaluate immediate exit. Example: route-card exit bearing 130°; current bearing to Bermuda 145° → Δ = 15°, exit-check now; 146° → exit. 4. Exiting too late → east of rhumb → upwind final miles in dying wind → disaster
Lupo applicability: HIGH if meander confirmed. Pre-calculate exit latitude at T-1 before race start and brief entire crew.
Risk: MEDIUM — main risk is overstaying. Enter with exit plan already decided. Position confidence is higher than T-CCR (connected to Stream), but exit discipline is harder because favorable current tempts boats to stay.
T-CL — Conservative Lane (Lupo's default)
T-CL is a meta-tactic that overlays the others. Not "go here" — "execute whichever route you choose with the fewest maneuvers, the cleanest sail changes, and the most pre-planned decisions." Every winner in the database (2012, 2014, 2018, 2022, 2024) includes T-CL. No winner executed a high-maneuver, opportunistic, mid-race-improvised strategy and won.
The principle: - Pick route at T-1 with navigator and Skipper; brief entire crew - Once on route: hold unless a confirmed-data trigger forces a change - Minimize sail changes inside high-stress phases (Stream, night watches, squalls) - "Choose before entry, hold through" — same protocol as Code 67 inside the Stream - Accept a slightly longer route in exchange for one the crew can sail at full speed
When it works: Crew has limited time on the boat (this applies to Lupo); forecast confidence moderate; fleet large; Bermuda High reaching forecast (dominant scenario).
When it fails: High-confidence current opportunity available — T-CL forfeits the gain; fleet gaining and only recovery is an aggressive lane; unusual high-confidence off-rhumb option clearly superior.
Operationalizing T-CL on Lupo: 1. Brief entire crew on route at T-1; print the route card; pin at nav station 2. Pre-decide reef and headsail change triggers (TWS thresholds, not "judgment calls") 3. Pre-set Gulf Stream sail before entry (Card 03); a peel inside is skipper-cleared, not a default 4. Define meander-exit latitude before entering (per T-ME) — pre-committed 5. For deviation: require (a) data trigger named, (b) maneuver count counted, (c) Skipper concurs
Lupo applicability: HIGH — this is Lupo's default tactic. Pairs with T-RH or T-PF as base layer, with T-ME on clean exit if meander available. Explicitly incompatible with T-CCR.
Risk: LOW. T-CL is the floor of expected performance — execute T-CL and finish upper-middle of fleet in a typical year. Combine with one well-chosen high-leverage tactic (T-PF or T-ME) and the upside is a class win.
T-WCE — Warm Core Eddy Avoidance
What a WCE is: Separated warm-water ring from Gulf Stream south wall. Clockwise (anti-cyclonic) flow. Western limb: northward (adverse for southbound boats). Eastern limb: southward (favorable).
Common trap: Boats heading south toward Bermuda get caught in WCE's southwestward flow on the western limb if east-of-rhumb and WCE centered near 32–33°N.
Identification: SST warm anomaly (4–9°F above background) at 32–34°N; altimetry SSH HIGH; RTOFS clockwise circulation.
Routing: Pass west of WCE center if possible. Time cost of going around is usually smaller than time lost through adverse western flow.
Lupo applicability: Always check for WCE in the post-Stream segment. Frequently underestimated.
Routing Hypothesis Labels
H- = coarse-grained routing hypothesis for a run or sensitivity worksheet. T- = fine-grained tactic catalog (the profiles above).
| Code | Label | Description | Catalog ref |
|---|---|---|---|
| H-RH | Rhumb baseline | Stay near rhumb, accept whatever current encountered | T-RH |
| H-PF | Pressure-first | Optimize for wind pressure; current secondary | T-PF |
| H-CF | Current-first | Route aggressively for favorable Stream; accept wind compromise | T-CF |
| H-CL | Conservative low-maneuver | Minimize gybes/tacks; accept slightly longer route | T-CL (Lupo's default) |
| H-HR | High-risk/high-reward | Exploit predicted eddy or ring; high model-dependency | T-CCR / T-ME / T-LA |
Sources
- Winner precedent & per-period encoding — winner_route_summary.md. This catalog is the T-* anchor source that forecast_analog_matcher.md and the daily brief deep-link into.
- CCR / WCE / meander definitions & identification thresholds — gulf_stream_framework.md (#ccr, #wce).
- Live crossing decision — stream_corridor_decision.md.
Changelog: catalog v1.2 → v2.1. T-CL profile added 2026-05-19; T-ME added from 2024 race analysis; Routing Hypothesis Labels relocated from PROJECT_PLAN.md 2026-05-28; Sources footer + year deep-links 2026-05-29.
PRE-RACE RESEARCH — not race-period routing advice. Updated 2026-05-29.