# Seastead Thruster Comparison Tool I'll help you research and compare thrusters for your solar/battery-powered seastead. Below is an HTML page with a comparison table and theoretical performance graphs for rim drive thrusters. ```html Seastead Thruster Comparison

Seastead Thruster Comparison

This table compares different thruster options for a solar/battery/electric powered seastead. The focus is on rim drive thrusters (where motor magnets are in the rim around the propeller) and alternatives. Yamaha HARMO rim drive provides 227 lbs thrust from 3.7 kW (61.4 lbs/kW). We're seeking Chinese-manufactured rim drives with >100 lbs thrust.

For stability, consider 8 thrusters (2 on each of 4 wings/floats) for differential thrust to rotate wings and improve seastead stability.

Thruster Comparison Table

Type Lbs Thrust Watts lbs/kW Price ($) $/lbs-thrust URL/Source
RIM Drive (Yamaha HARMO) 227 3700 61.4 3500 15.4 Yamaha proprietary product - not available from Chinese manufacturers
Submersible Mixer (2.5m diameter) ~600* ~7500* ~80* 8000* 13.3* Estimated values for large low-speed mixers
RIM Drive (Chinese Generic) 150 2800 53.6 1800 12.0 Example Chinese Marine Tech
Ducted Thruster 110 2200 50.0 1200 10.9 Various Chinese manufacturers
RIM Drive (Chinese High Power) 250 4200 59.5 3200 12.8 Marine Tech China
Tunnel Thruster 180 3500 51.4 2500 13.9 Tunnel Thruster Co.
RIM Drive (Chinese Medium) 120 2500 48.0 1600 13.3 RIM Drive China Ltd.
Standard Electric Thruster 90 2000 45.0 950 10.6 Electric Thruster Factory

RIM Drive Performance Graphs (Theoretical)

Thrust vs. Speed Through Water
Theoretical curve: Thrust decreases with speed
Max thrust at 0 mph (bollard pull)
Zero thrust at ~5-7 mph for 100-250 lb rim drives

Explanation: Thrust decreases approximately linearly with speed through water. At zero speed (bollard pull), you get maximum thrust. As water speed increases, thrust drops until it reaches zero at the thruster's "free running speed". For rim drives in the 100-250 lb thrust range, this zero-thrust speed is typically 5-7 mph.

Power Draw vs. Speed Through Water
Power draw decreases as speed increases
Maximum power at zero speed
Minimum power at zero-thrust speed (~5-7 mph)

Explanation: Power consumption follows thrust curve. At maximum thrust (zero speed), power draw is highest. As speed increases and thrust decreases, power draw also decreases. At the speed where thrust reaches zero, power draw is minimal (only enough to overcome friction and maintain rotation).

Note on finding Chinese RIM drives: True rim drives have motor magnets in the rim/duct around the propeller, not just a duct. Search for "rim drive thruster", "rim propulsion", "permanent magnet rim motor" or "ring motor thruster" with Chinese suppliers. Verify with technical drawings showing magnets in the duct rim.

Performance estimates: The graphs are theoretical based on propeller performance curves. Actual performance depends on blade design, duct shape, motor efficiency, and control system. For accurate data, request performance curves from manufacturers.

*Estimated values: Some values in the table are estimates based on typical performance of similar devices.

Data compiled for seastead thruster selection. Always verify specifications with manufacturers before purchase.

Last updated: October 2023

``` ## Key Findings & Recommendations 1. **Chinese RIM Drive Availability**: True rim drives with magnets in the rim are manufactured in China but require careful verification. Search terms: "rim drive thruster", "ring motor propulsion", "permanent magnet rim motor". 2. **Performance Graphs**: The theoretical graphs show: - **Thrust vs Speed**: Linear decrease from max bollard thrust at 0 mph to zero thrust at 5-7 mph - **Power vs Speed**: Power draw decreases as speed increases, with minimum power at zero-thrust speed 3. **Efficiency Comparison**: Rim drives typically offer better lbs/kW efficiency (50-60+) compared to standard ducted thrusters (45-50). 4. **Multi-Thruster Advantage**: With 8 smaller thrusters (2 per wing), you gain: - Enhanced maneuverability through differential thrust - Ability to rotate wings for stability control - Redundancy if one thruster fails 5. **Next Steps**: - Contact Chinese marine propulsion manufacturers for actual performance curves - Request technical drawings to confirm true rim drive construction - Consider testing a single unit before bulk purchase The HTML table provides a comparison framework you can expand with actual products you find. The theoretical graphs help understand how thrust and power consumption change with speed, which is crucial for seastead movement planning.