```html Seastead Safety • Man Overboard Prevention System
Open Source Safety Initiative

Making
Man Overboard
Events Survivable

A smartphone-based detection system for the next generation of seasteads and family yachts.

The Seastead Platform

A stable, low-drag trimaran-style seastead designed for long-term living with exceptional safety features.

Superstructure

70ft × 35ft triangular truss structure, 7ft ceiling height, fully enclosed with extensive glass for visibility. Low waterline area design.

Buoyancy System

Three 19ft NACA 0030 foil legs (10ft chord), 50% submerged. RIM drive thrusters on each leg for propulsion and maneuverability.

Stabilization

Three small airplane-style stabilizers with active elevator control. 5° sloped leg bottoms for high-speed lift.

The Human Cost of Man Overboard

Falls overboard remain one of the most dangerous incidents at sea, even on modern vessels.

~120 deaths/year
United States (USCG data)
Falls overboard account for approximately 18-22% of all recreational boating fatalities. The actual number of MOB events is significantly higher, as many are successfully recovered.
Source: U.S. Coast Guard Recreational Boating Statistics (2022-2023)
Global Impact
Estimated worldwide recreational MOB fatalities 400–800
Survival rate after 15 minutes in water (avg temp) ~50%
Time for most yachts to complete a MOB turn 2–8 minutes
Key insight: Most fatalities occur because the vessel cannot return to the person quickly enough or cannot locate them in waves.

Proposed Smartphone-Based MOB System

Leveraging devices people already carry to create an instant, automatic response.

How It Works

1
Continuous Check-in
Phone pings base station every 1–3 seconds via Bluetooth (preferred) or Wi-Fi. Location recorded at base.
2
Zero-G Detection
Accelerometer detects free-fall before water impact. Triggers immediate alert with precise timestamp and last known position.
3
Automatic Response
After configurable timeout (e.g., 6 seconds), the seastead executes fast stop, reverses to last known position, and sounds alarm.

Key Advantages

Instant Water Detection
2.4 GHz signals (Wi-Fi/Bluetooth) are blocked instantly by water — no need to wait for GPS drift.
Zero Hardware Cost
Uses phones people already carry. Open-source software only.
Perfect for Solo Sailors
Seastead can return to the exact location autonomously. Built-in ladders allow self-rescue.

Technical Feasibility

This system is realistic to build today using modern AI-assisted development tools.

Battery Impact

Optimized (BLE every 5s + Wi-Fi fallback) 12-20% extra drain
Most modern phones can still last a full day. The app should be designed with aggressive power management:
  • Bluetooth Low Energy (BLE) for primary communication
  • Background location updates only when moving
  • "Never sleep" setting guidance for users

Development with AI

Recommended Stack
Flutter Cross-platform mobile
Node.js / Python Server on seastead
React Native Alternative
AI Tools
Cursor (VS Code + Claude)
Claude Projects / Claude Code
GitHub Copilot
A functional prototype (phone app + simple server) can be built in 1–2 weeks by an experienced developer with AI assistance.
Open Source Potential
This is an excellent candidate for an open-source project. Existing family yachts with Starlink/Wi-Fi could install the server software on a Raspberry Pi or existing onboard computer and immediately improve safety at zero hardware cost.

Existing Solutions & Lessons Learned

Current Commercial Options

Dedicated MOB Beacons
AIS MOB devices (e.g., Ocean Signal, ACR) — very reliable but cost $300–$600 per unit.
Wearable Systems
CrewWatcher, SeaTag, and some Garmin systems use Bluetooth beacons or dedicated watches.

Critical Issues to Address

OS Background Restrictions
iOS aggressively kills background apps. Solution: Use location services + background fetch + "Always" location permission.
False Alarms
Must use multi-factor confirmation (e.g., 3 missed pings + motion analysis) before triggering full MOB response.
Privacy & Liability
Clear consent required. Open source code helps with transparency and reduces liability concerns.
Phone Death / Forgotten Device
Add door sensor (optional) and require users to charge phone before going on deck.

Let's Build This Together

This system could save lives on existing yachts today while we develop the next generation of seasteads.

The code can be written primarily by AI tools like Cursor and Claude, dramatically reducing development time.
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