summaryrefslogtreecommitdiff
path: root/android-app/app/src/main/assets/docs
diff options
context:
space:
mode:
authorClaude <noreply@anthropic.com>2026-04-23 23:10:11 +0000
committerClaude <noreply@anthropic.com>2026-04-23 23:10:11 +0000
commite1db9200e9d44c10450361cc8984a45b2eda87b7 (patch)
tree21bdfca02491e6ff4cde7a22673c821c0a03e108 /android-app/app/src/main/assets/docs
parent55509f579b4d074f01237dd90791b6d25aaec3cd (diff)
parenteb78d317c722234a7ef2c501c68c9aa730ec2758 (diff)
Merge origin/main — unite all work onto one branch
Brings in dev log (NavLogger), UnitPrefs, MapLayerManager, HUD views, conditions throttling, track save/load pipeline, improved ParticleWindView (antimeridian-aware, dynamic particle count), Snackbar error surfacing, and all other main-branch work from the prior session. Combined with master's hardware source flags, vessel registry, crew management, thermal alarm, CPA collision alerts, and track stats. Also documents primary branch policy in CLAUDE.md and .agent/config.md: all work merges to main, never master. https://claude.ai/code/session_011h2dXbgXg3PesQMmQUNTCW
Diffstat (limited to 'android-app/app/src/main/assets/docs')
-rw-r--r--android-app/app/src/main/assets/docs/colregs_reference.md230
-rw-r--r--android-app/app/src/main/assets/docs/migrate_navionics.md56
-rw-r--r--android-app/app/src/main/assets/docs/migrate_sea_people.md59
-rw-r--r--android-app/app/src/main/assets/docs/sailing_reference.md206
4 files changed, 551 insertions, 0 deletions
diff --git a/android-app/app/src/main/assets/docs/colregs_reference.md b/android-app/app/src/main/assets/docs/colregs_reference.md
new file mode 100644
index 0000000..6e5c39a
--- /dev/null
+++ b/android-app/app/src/main/assets/docs/colregs_reference.md
@@ -0,0 +1,230 @@
+# ColRegs — Rules of the Road
+
+International Regulations for Preventing Collisions at Sea (COLREGS), 1972 with amendments. This is a summary reference; consult the official text for legal purposes.
+
+---
+
+## Part A — General (Rules 1–3)
+
+**Rule 1 — Application**
+Applies to all vessels on the high seas and connected navigable waters.
+
+**Rule 2 — Responsibility**
+Nothing in these rules exonerates a vessel, owner, master, or crew from the consequences of neglect. Good seamanship always applies.
+
+**Rule 3 — Definitions**
+- *Vessel* — any watercraft, including seaplanes and WIG craft
+- *Power-driven vessel* — any vessel propelled by machinery
+- *Sailing vessel* — under sail only; if engine is running, she is power-driven
+- *Vessel engaged in fishing* — using nets, lines, trawls that restrict maneuverability
+- *Underway* — not at anchor, aground, or made fast to shore
+- *Restricted visibility* — fog, mist, falling snow, heavy rain, sandstorm, or similar conditions
+
+---
+
+## Part B — Steering and Sailing Rules
+
+### Section I — Conduct in Any Visibility (Rules 4–10)
+
+**Rule 4** — Applies in any condition of visibility.
+
+**Rule 5 — Look-out**
+Every vessel shall maintain a proper look-out at all times by sight, hearing, and all available means.
+
+**Rule 6 — Safe Speed**
+Every vessel shall proceed at a safe speed. Factors: visibility, traffic density, vessel maneuverability, background lights at night, radar state, sea state.
+
+**Rule 7 — Risk of Collision**
+Risk exists if the compass bearing of an approaching vessel does not appreciably change. When in doubt, assume risk exists.
+
+**Rule 8 — Action to Avoid Collision**
+- Action must be positive, made in ample time, and large enough to be readily apparent
+- Course or speed changes should be large enough to be noticed
+- If necessary, stop or reverse
+
+**Rule 9 — Narrow Channels**
+- Keep to the starboard side of a narrow channel
+- Vessels under 20 m or sailing vessels shall not impede vessels that can safely navigate only in the channel
+- Overtaking only when safe and the overtaken vessel signals agreement
+- Do not cross a narrow channel if it impedes a through-traffic vessel
+
+**Rule 10 — Traffic Separation Schemes**
+- Join/leave at end; if joining from side, at acute angle
+- Keep out of separation zones
+- Crossing traffic does so at right angles where practicable
+- Inshore traffic zones: use only if < 20 m, or sailing, or fishing
+
+---
+
+### Section II — Conduct in Sight of One Another (Rules 11–18)
+
+**Rule 11** — Applies to vessels in sight of one another.
+
+**Rule 12 — Sailing Vessels**
+- Vessel on port tack gives way to vessel on starboard tack
+- Both on same tack: windward vessel gives way to leeward vessel
+- Port tack vessel cannot determine which tack the other is on: gives way
+
+**Rule 13 — Overtaking**
+Any vessel overtaking gives way. Overtaking means coming up from more than 22.5° abaft the other's beam. Overtaking status persists until clear and past.
+
+**Rule 14 — Head-on Situation**
+Both vessels altering course to starboard so each passes on the port side of the other. Applies when risk of collision exists and vessels are nearly end-on.
+
+**Rule 15 — Crossing Situation**
+The vessel that has the other on its own starboard side gives way (the "burdened" or give-way vessel). The stand-on vessel is on the right.
+
+**Rule 16 — Action by Give-way Vessel**
+Take early and substantial action to keep well clear.
+
+**Rule 17 — Action by Stand-on Vessel**
+- May take action to avoid collision by own maneuver alone when it becomes apparent the give-way vessel is not taking sufficient action
+- Must take action when collision cannot be avoided by give-way vessel alone
+- Course change to port for a vessel on your port side is avoided if possible
+
+**Rule 18 — Responsibilities Between Vessels**
+
+Hierarchy (higher number gives way to all above):
+1. Vessel not under command (NUC)
+2. Vessel restricted in ability to maneuver (RAM)
+3. Vessel constrained by draft
+4. Vessel engaged in fishing
+5. Sailing vessel
+6. Power-driven vessel underway
+
+*Note:* Sailing and power vessels give way to NUC, RAM, constrained, and fishing vessels. A power vessel gives way to a sailing vessel.
+
+---
+
+### Section III — Conduct in Restricted Visibility (Rule 19)
+
+**Rule 19 — Restricted Visibility**
+- Proceed at safe speed adapted to conditions
+- Have engines ready for immediate maneuver
+- On hearing fog signal apparently forward of beam: reduce to bare steerage or stop
+- Avoid alteration of course to port for a vessel forward of beam (except overtaking)
+- Avoid alteration toward a vessel abeam or abaft beam
+
+---
+
+## Part C — Lights and Shapes (Rules 20–31)
+
+### Lights (Rules 20–22)
+
+**Rule 20 — Application**
+Lights required from sunset to sunrise and in restricted visibility.
+
+**Rule 21 — Definitions**
+- *Masthead light* — white forward light, 225° arc
+- *Side lights* — red (port) and green (starboard), 112.5° each
+- *Stern light* — white aft, 135° arc
+- *Towing light* — yellow, same arc as stern light
+- *All-round light* — 360° arc
+- *Flashing light* — 120+ flashes/minute
+
+**Rule 22 — Visibility of Lights**
+
+| Vessel size | Masthead | Side | Stern | All-round |
+|---|---|---|---|---|
+| ≥ 50 m | 6 nm | 3 nm | 3 nm | 3 nm |
+| 12–50 m | 5 nm | 2 nm | 2 nm | 2 nm |
+| 7–12 m | 3 nm | 1 nm | 2 nm | 2 nm |
+| < 7 m | — | — | — | 2 nm |
+
+---
+
+### Light Combinations to Know
+
+**Under power (≥ 50 m):** Two masthead lights (forward lower, aft higher) + sidelights + stern light
+
+**Under power (< 50 m):** One masthead light + sidelights + stern light
+
+**Under sail (underway):** Sidelights + stern light only. *No masthead light when under sail.*
+
+**Sail + engine:** Power-driven vessel rules apply — show cone (point down) by day.
+
+**At anchor (< 50 m):** One white all-round light forward.
+**At anchor (≥ 50 m):** White all-round forward + aft.
+
+**Not under command:** Two red all-round lights (vertical). If making way: add sidelights + stern light.
+
+**Restricted in ability to maneuver:** Red-white-red all-round lights (vertical). If making way: add masthead + sidelights + stern.
+
+**Vessel aground:** Anchor lights + two red all-round lights (vertical).
+
+**Towing vessel:** Extra masthead light(s) + yellow towing light instead of (or in addition to) stern light.
+
+**Fishing (trawling):** Green over white all-round (vertical) + sidelights + stern if making way.
+**Fishing (other):** Red over white all-round (vertical) + sidelights + stern if making way + white toward gear if gear > 150 m.
+
+**Pilot vessel on duty:** White over red all-round lights.
+
+---
+
+### Day Shapes (Rule 28)
+
+| Shape | Vessel Type |
+|---|---|
+| Black ball | At anchor |
+| Black cone (apex down) | Sailing vessel with engine |
+| Two black balls (vertical) | Not under command |
+| Ball-diamond-ball (vertical) | Restricted in ability to maneuver |
+| Black cylinder | Constrained by draft |
+| Basket | Engaged in fishing |
+| Cone (apex up) | Vessel being towed (if requested) |
+
+---
+
+## Part D — Sound and Light Signals (Rules 32–37)
+
+**Rule 32 — Definitions**
+- *Short blast* — about 1 second
+- *Prolonged blast* — 4–6 seconds
+
+**Rule 33 — Equipment**
+- ≥ 12 m: whistle + bell
+- ≥ 100 m: also gong
+
+**Rule 34 — Maneuvering and Warning Signals**
+
+| Signal | Meaning |
+|---|---|
+| 1 short | I am altering course to starboard |
+| 2 shorts | I am altering course to port |
+| 3 shorts | I am operating astern propulsion |
+| 5+ shorts (rapid) | Danger / doubt signal |
+| 1 prolonged | Vessel leaving berth |
+
+**Rule 35 — Sound Signals in Restricted Visibility**
+
+| Signal | Vessel |
+|---|---|
+| 1 prolonged (≤ 2 min) | Power-driven vessel making way |
+| 2 prolonged (≤ 2 min) | Power-driven vessel underway but stopped |
+| 1 long + 2 short (≤ 2 min) | NUC, RAM, sailing, fishing, towing |
+| 1 long + 3 short | Vessel being towed (last vessel) |
+| Rapid bell (5 sec, ≤ 1 min) | At anchor (< 100 m) |
+| Bell + gong (≤ 1 min) | At anchor (≥ 100 m) |
+| 3 strokes + rapid bell + 3 strokes | Vessel aground |
+
+**Rule 36 — Attention Signal**
+Five or more short and rapid blasts. Also a light signal of the same pattern.
+
+**Rule 37 — Distress Signals**
+Gun fired at ~1 min intervals; continuous foghorn; SOS (···−−−···); MAYDAY by voice; orange smoke; flames; parachute flare; dye; square flag + ball; high-intensity white light flashing; radio alarm signal.
+
+---
+
+## Part E — Exemptions (Rule 38)
+
+Older vessels may be exempt from some lighting requirements for a period of years after the rules came into force.
+
+---
+
+## Quick Memory Aids
+
+**Starboard right-of-way:** When another vessel is on your starboard side in a crossing situation, YOU give way.
+
+**Lights mnemonic — red over green, sailing machine:** A sailing vessel shows red (port side) and green (starboard) sidelights plus a white stern light. No masthead light while under sail alone.
+
+**The hierarchy:** NUC → RAM → Constrained → Fishing → Sail → Power
diff --git a/android-app/app/src/main/assets/docs/migrate_navionics.md b/android-app/app/src/main/assets/docs/migrate_navionics.md
new file mode 100644
index 0000000..83b28fa
--- /dev/null
+++ b/android-app/app/src/main/assets/docs/migrate_navionics.md
@@ -0,0 +1,56 @@
+# Migrating from Navionics
+
+Welcome to Nav. This guide covers the key differences and how to move your data over.
+
+---
+
+## What's Different
+
+| Feature | Navionics | Nav |
+|---|---|---|
+| Charts | Navionics SonarChart + Raster | OpenFreeMap vector tiles |
+| Track recording | In-app GPX | GPX saved to Documents/Nav/ |
+| Trip log | Voyage log | Voice log (transcribed) |
+| Departure planning | None | Pre-trip briefing with sail plan |
+| Wind overlay | Basic | Wind particles + hourly forecast |
+
+---
+
+## Exporting Your Tracks from Navionics
+
+1. Open Navionics on your phone or tablet
+2. Go to **My Charts → Tracks**
+3. Tap a track → **Share → Export GPX**
+4. Save or AirDrop the `.gpx` file to your device
+
+---
+
+## Importing Tracks into Nav
+
+Nav automatically reads GPX files from the **Documents/Nav/** folder on your device.
+
+1. Move your exported `.gpx` files to `Documents/Nav/` using the Files app
+2. Re-open Nav — tracks are loaded on startup
+3. Similar-conditions trip comparison in the Pre-Trip Briefing will use these tracks
+
+---
+
+## Waypoints
+
+Nav does not currently manage waypoints. Use Navionics or a dedicated chart plotter for waypoint routing. Nav focuses on departure briefing, track recording, and the sail log.
+
+---
+
+## Charts
+
+Nav uses **OpenFreeMap** vector tiles. These are free, fast, and work well for coastal cruising. They do not include depth contours or hazard overlays — continue using Navionics or a NOAA chart app for navigation in unfamiliar waters.
+
+---
+
+## Daily Workflow
+
+**Before you sail:** Open the **Safety → Plan Trip** screen for your departure briefing — sail plan, heading recommendation, watch items, and a look at how conditions will change over your trip window.
+
+**On the water:** Tap **Log** to dictate voice notes. The GPS track records automatically when you tap the record button.
+
+**After you return:** The post-trip report summarises distance, duration, and max SOG.
diff --git a/android-app/app/src/main/assets/docs/migrate_sea_people.md b/android-app/app/src/main/assets/docs/migrate_sea_people.md
new file mode 100644
index 0000000..b1920b4
--- /dev/null
+++ b/android-app/app/src/main/assets/docs/migrate_sea_people.md
@@ -0,0 +1,59 @@
+# Migrating from Sea People
+
+Welcome to Nav. This guide covers what transfers over and what works differently.
+
+---
+
+## What's Different
+
+| Feature | Sea People | Nav |
+|---|---|---|
+| Social feed | Community posts | Not applicable — Nav is single-user |
+| Trip log | Text entries + photos | Voice log (transcribed audio) |
+| Boat profiles | Basic boat card | Detailed sail inventory with reef points |
+| Weather | Integrated forecast | Open-Meteo hourly + NOAA marine |
+| Departure planning | Manual notes | Pre-trip briefing with sail plan & route |
+
+---
+
+## Exporting Your Log from Sea People
+
+1. Open Sea People → **Profile → My Logs**
+2. Use the **Export** option (CSV or PDF depending on your version)
+3. Save entries you want to keep for reference
+
+Nav's voice log works differently — entries are dictated on the water and transcribed. You won't be able to import Sea People entries directly, but you can review them alongside Nav going forward.
+
+---
+
+## Boat Profiles
+
+Nav stores a detailed boat profile with your sail inventory:
+
+- **Headsails** with wind range for each (e.g. 155% Genoa ≤ 13 kt, 100% Jib 10–21 kt, 65% Blade 18+ kt)
+- **Main reef points**
+- **Hull length** (used for hull-speed estimates in the departure briefing)
+
+Your boats are pre-seeded on first launch. Profiles are stored locally and used in the **Pre-Trip Briefing** to give sail recommendations specific to your boat.
+
+---
+
+## Trip Log Workflow
+
+**On the water:** Tap the **Log** tab and use the microphone button to dictate a note. Notes are timestamped with your GPS position.
+
+**Voice notes work well for:**
+- Sea state observations ("1.5m swell, 10s period, comfortable")
+- Traffic ("fishing vessel on starboard, gave way")
+- Sail changes ("reefed main at 18 kt")
+- Time stamps ("rounded the point, heading west")
+
+---
+
+## Daily Workflow
+
+**Before you sail:** Safety → Plan Trip for your departure briefing.
+
+**On the water:** Log tab for voice notes; tap the record FAB to start the GPS track.
+
+**After you return:** The post-trip report generates a narrative summary you can save or share.
diff --git a/android-app/app/src/main/assets/docs/sailing_reference.md b/android-app/app/src/main/assets/docs/sailing_reference.md
new file mode 100644
index 0000000..7fc7bdb
--- /dev/null
+++ b/android-app/app/src/main/assets/docs/sailing_reference.md
@@ -0,0 +1,206 @@
+# Sailing Quick Reference
+
+---
+
+## Points of Sail
+
+The point of sail describes the angle between the boat's heading and the true wind direction.
+
+| Point of Sail | True Wind Angle | Description |
+|---|---|---|
+| In irons | 0–30° | Head-to-wind, sails luffing, no drive |
+| Close hauled | ~30–45° | Sailing as close to the wind as possible |
+| Close reach | ~45–60° | Between close hauled and beam reach |
+| Beam reach | ~90° | Wind directly abeam — often fastest point |
+| Broad reach | ~120–150° | Wind on the quarter — comfortable, fast |
+| Run | ~150–180° | Wind from directly behind |
+
+**No-go zone:** ~0–30° on either side of the wind — the boat cannot make progress sailing directly into the wind.
+
+---
+
+## Tacking vs. Gybing
+
+**Tacking** — turning the bow through the wind (bow crosses the wind). The boom swings across from one side to the other. Used to head upwind.
+
+**Gybing** — turning the stern through the wind (stern crosses the wind). The boom can swing violently — always control the mainsheet. Used to change direction downwind.
+
+---
+
+## Sail Trim Basics
+
+**Telltales** — strips of yarn or fabric on the sail.
+- Both telltales streaming aft → sail trimmed correctly
+- Windward telltale lifting → sheet in (trim), or bear away
+- Leeward telltale lifting → sheet out (ease), or head up
+
+**In irons fix:** Let sails luff, push boom to one side, fall off onto a tack.
+
+**Reef** — reducing sail area by partially lowering the mainsail and tying off the excess. Reef before you think you need to. Typical thresholds: first reef ~15–18 kt, second reef ~21–25 kt.
+
+---
+
+## Hull Speed
+
+The theoretical maximum displacement hull speed:
+
+**Hull speed (kt) ≈ 1.34 × √(waterline length in feet)**
+
+| LOA | Hull Speed |
+|---|---|
+| 20 ft | ~6.0 kt |
+| 23 ft | ~6.4 kt |
+| 30 ft | ~7.3 kt |
+| 40 ft | ~8.5 kt |
+
+A modern fin-keel boat can exceed hull speed in planing conditions (surfing downwind in big waves).
+
+---
+
+## Navigation Lights — Quick Reference
+
+| Situation | What You See | What It Is |
+|---|---|---|
+| Red + green + white | Two side lights + stern | Head-on approach |
+| Red only | Port sidelight | Vessel crossing left-to-right in front of you |
+| Green only | Starboard sidelight | Vessel crossing right-to-left — you are give-way |
+| White only (masthead) + green | Overtaking from starboard | Vessel overtaking you on starboard |
+| Two white (stacked) + red/green | Two masthead lights | Large ship (≥50 m) underway under power |
+| Red + white (all-round, vertical) | Not under command | Give way — vessel cannot maneuver |
+| Green + white (all-round, vertical) | Trawler | Give way — engaged in fishing |
+| White all-round only | At anchor | Avoid — vessel at anchor |
+| White + red all-round (vertical) | Pilot vessel | Pilot boat on duty |
+
+---
+
+## Day Shapes
+
+| Shape | Meaning |
+|---|---|
+| ⚫ Black ball | Vessel at anchor |
+| 🔻 Black cone (apex down) | Sailing vessel motorsailing |
+| ⚫ ⚫ Two balls (vertical) | Not under command |
+| ⚫ ◆ ⚫ Ball-diamond-ball | Restricted in ability to maneuver |
+| ▬ Black cylinder | Constrained by draft |
+
+---
+
+## Beaufort Wind Scale
+
+| Force | kt | Description | Sea State |
+|---|---|---|---|
+| 0 | < 1 | Calm | Mirror smooth |
+| 1 | 1–3 | Light air | Ripples |
+| 2 | 4–6 | Light breeze | Small wavelets |
+| 3 | 7–10 | Gentle breeze | Scattered whitecaps |
+| 4 | 11–16 | Moderate breeze | Moderate waves, frequent whitecaps |
+| 5 | 17–21 | Fresh breeze | Long waves, many whitecaps, spray |
+| 6 | 22–27 | Strong breeze | Large waves, spray, whitecaps everywhere |
+| 7 | 28–33 | Near gale | Sea heaping up, foam streaks |
+| 8 | 34–40 | Gale | Moderately high waves, edges blowing |
+| 9 | 41–47 | Strong gale | High waves, dense foam, visibility affected |
+| 10 | 48–55 | Storm | Very high waves, sea white, heavy sea roll |
+| 11 | 56–63 | Violent storm | Exceptionally high waves |
+| 12 | 64+ | Hurricane force | Air filled with foam, visibility nil |
+
+---
+
+## Common Knots
+
+**Bowline** — fixed loop that won't slip. The classic sailing knot. "The rabbit comes out of the hole, round the tree, and back down the hole."
+
+**Cleat hitch** — securing a line to a cleat. Take a round turn around the base, then two figure-8 turns, then one locking hitch over the horn.
+
+**Clove hitch** — temporary attachment to a post or rail. Two half hitches; easy to adjust and release.
+
+**Figure-eight** — stopper knot. Prevents a line from running through a block or fairlead.
+
+**Round turn and two half hitches** — secure, adjustable attachment to a ring or rail.
+
+**Reef knot** — joining two lines of similar diameter. Right over left, left over right. Not for critical loads — use a sheet bend for mismatched diameters.
+
+**Sheet bend** — joining two lines of different diameter. The thicker line forms the loop.
+
+**Rolling hitch** — attaching to another line or spar under load. Grips when pulled along the spar.
+
+**Anchor hitch (fisherman's bend)** — the correct knot for attaching a line to an anchor.
+
+---
+
+## Buoyage — IALA System B (Americas, Japan, Philippines, Korea)
+
+**Red right returning** — red buoys on the starboard side when returning from sea.
+
+| Mark | Shape | Color | Top Mark | Meaning |
+|---|---|---|---|---|
+| Port lateral | Can / pillar | Red | None | Keep to starboard (IALA-B: keep red to starboard) |
+| Starboard lateral | Nun / cone | Green | Cone | Keep to port |
+| Safe water | Sphere | Red + white vertical stripes | Sphere | Safe water on all sides |
+| Isolated danger | Pillar / spar | Black + red bands | Two black balls | Isolated danger, safe water around it |
+| Special mark | Any | Yellow | Yellow X | Special purpose (mooring, racing, TSS) |
+| Cardinal (N) | Pillar / spar | Black over yellow | Two cones pointing up | Pass to the north |
+| Cardinal (S) | Pillar / spar | Yellow over black | Two cones pointing down | Pass to the south |
+| Cardinal (E) | Pillar / spar | Black-yellow-black bands | Cones base-to-base | Pass to the east |
+| Cardinal (W) | Pillar / spar | Yellow-black-yellow bands | Cones point-to-point | Pass to the west |
+
+*IALA-A (Europe, Africa, most of Asia):* Red/green assignments are reversed — "red left returning."
+
+---
+
+## VHF Radio Channels
+
+| Channel | Use |
+|---|---|
+| 16 | **International distress, safety, and calling** — always monitor |
+| 22A | US Coast Guard working channel |
+| 9 | Boater calling channel (US) |
+| 6 | Ship-to-ship safety communications |
+| 13 | Bridge-to-bridge (1 watt) |
+| 70 | DSC digital selective calling — do not use for voice |
+| 24, 25, 26, 27, 28 | Public correspondence (marine operator) |
+
+**MAYDAY procedure:**
+1. MAYDAY MAYDAY MAYDAY
+2. This is [vessel name × 3]
+3. MAYDAY [vessel name]
+4. Position
+5. Nature of distress
+6. Number of persons aboard
+7. Any other information
+8. Over
+
+---
+
+## Tide and Current Basics
+
+**Flood** — tide coming in (rising sea level).
+**Ebb** — tide going out (falling sea level).
+**Slack** — the period of minimal current around high and low water.
+
+Rule of twelfths — tide rises/falls unevenly:
+- Hour 1: 1/12 of range
+- Hour 2: 2/12 of range
+- Hour 3: 3/12 of range ← fastest
+- Hour 4: 3/12 of range ← fastest
+- Hour 5: 2/12 of range
+- Hour 6: 1/12 of range
+
+**Spring tides** — larger range; occur near new and full moon.
+**Neap tides** — smaller range; occur near quarter moons.
+
+---
+
+## Distress Signals (Rule 37 / SOLAS)
+
+Any of these signals indicate distress and request assistance:
+- Red parachute flare or red hand flare
+- Orange smoke signal
+- MAYDAY spoken over radio (Ch 16)
+- SOS (···−−−···) by any signaling method
+- Continuous foghorn sound
+- Gun fired at approximately 1-minute intervals
+- Flames on the vessel
+- Slowly and repeatedly raising and lowering both arms
+- Square flag with ball above or below it
+- Orange dye in water
+- Satellite EPIRB signal