ONBOARD CARD 10 — Tactical Scenarios
Rev: v1.1 · Updated: 2026-06-01 · Change: trimmed to one page (light / heavy / adverse current)
Light Air Shutdown
Trigger: TWS <6 kts sustained, expected to continue · Common: late race near Bermuda; mid-ocean W-PL/W-BS
TL;DR
- Minimize crew movement — foredeck seated and stationary; no movement unless executing a task.
- Pre-stage the transition sail before pressure fills; brief the expected fill direction.
- Steer for the dark patches; ease halyards slightly (draft forward); don't over-trim.
- A1-1 is the workhorse; Code 67 for mid reaching (80–120°), J1 for tight.
- Wake Navigator if pressure fills from a new direction >6 kts.
| TWS | Best sail |
|---|---|
| 3–5 kts, any angle | A1-1 |
| 5–8 kts, reaching | Code 67 / A1-1 |
| <3 kts | Accept drift; A1-1; patient |
Red flags: sister boats catching >1 nm/h → trim/sail problem, not luck · wind filling from a new direction → pre-stage + brief the transition.
Heavy Air Reaching
Trigger: TWS >22 kts reaching/broad (TWA 60–140°) · Common: post-front W-CF/W-PF; strong gradient
TL;DR
- Carbon rig fails without warning — reduce sail earlier than intuition. Reef #1 pre-rigged before 22 kts.
- Main trim: vang hard, traveler to leeward, ease mainsheet — do not luff.
- Wake all watch on spike >30 kts; Skipper on any structural concern.
| TWS / TWA | Preferred sail |
|---|---|
| 22–28 kts, TWA 80–120° | A3 |
| 22–28 kts, TWA 120–160° | A3 or SS (A4 only if ≥140°) |
| 28–35 kts, any reach | J3 (kite down first) |
| >35 kts | J4 + reef #1 |
Kite down if: >26 kts sustained + disorganized seas · helm can't control the boat (immediately) · night + >22 kts + no experienced trimmer.
Red flags: boat speed >12 kts in confused seas → control over speed · shroud/runner vibration → check rig now · night + >25 kts → broach risk high on an unfamiliar boat.
Adverse Current Decision
Trigger: GPS/log delta >1 kt adverse, persistent >30 min · Common: north-wall approach, Stream crossing, WCE south of Stream
TL;DR
- Detour calc is a Navigator task — protect 30–45 min; don't act on <15–20 min of observation.
- Skipper + Navigator disagree → default conservative. Then commit and sail fast.
- Wake Navigator on delta >1 kt persistent >30 min; Skipper on >2 kts adverse with >2 h detour gain.
| Adverse current | VMG at 8 kts STW | Detour rule | |
|---|---|---|---|
| 0.5 kts | −6% | <1 kt → bash through | |
| 1.5 kts | −19% | >2 kts + zone >50 nm → 20–30 nm detour usually faster | |
| 2.5 kts | −31% | >3 kts + zone >80 nm → 40–50 nm detour worth calculating | |
| 3.5 kts | −44% | past halfway through the zone → stay the course |
Red flags: SOG <5 kts while log shows 8 → >3 kts adverse, don't bash · same-direction adverse >4 h → a feature, not a transient · other-class boats making better VMG elsewhere → look at what they're doing.
PRE-RACE RESEARCH — not race-period routing advice