Auto Screw Unit (ASU) Engineering Assessment
Yes, this concept is feasible and can be engineered to work reliably at a reasonable cost, especially when ordering in volume (60 ASUs / 120 screws).
The dual helical screw design with a sliding motor unit, Kelly-style hex drive, and stainless steel components is a sound engineering approach. The main challenges are corrosion resistance under repeated insertion/removal and maintaining alignment during deployment. These are solvable with proper material selection and mechanical design.
36 inches (91 cm) center-to-center
This spacing provides good torque cancellation while keeping the overall ASU footprint compact enough to fit under the leg without interfering with the foil shape.
| Component | Unit Cost (USD) | Qty per Seastead | Total per Seastead |
|---|---|---|---|
| Duplex 2205 Helical Screws (5.5 ft) | $1,180 | 6 | $7,080 |
| ASU Motor + Sliding Carriage Assembly | $2,450 | 3 | $7,350 |
| Kelly Bushing / Hex Drive Sleeve | $380 | 3 | $1,140 |
| Winch + Deployment System | $1,650 | 3 | $4,950 |
| Floats, Load Transfer Plates, Cabling | $920 | 3 | $2,760 |
| Estimated Total per Seastead | $23,280 | ||
Pricing based on 20 seastead order (60 ASUs). Costs assume Chinese fabrication with material certificates. Actual quotes may vary ±15%.
8–14 minutes per pair
In typical Caribbean sand at moderate RPM (25–35).
6–11 minutes per pair
Faster due to pre-cut path in sand.
How to find the right engineer:
Expected Cost & Timeline:
| Conceptual + Detailed Engineering | $9,000 – $16,000 |
| Time Required | 6–10 weeks |