Inflatable Kayak Hydrodynamics — Drag, Stability, and Tracking Performance
Comparative hydrodynamic analysis of inflatable kayak hull forms including V-hull, flat-bottom, and tunnel-hull designs across speed, tracking, and stability metrics.
Abstract
Three inflatable kayak hull designs were tested in a tow-tank facility to measure hydrodynamic drag, tracking accuracy, and stability across a range of speeds (2-8 km/h). The study provides quantitative data for optimizing inflatable kayak hull form for recreational, touring, and fishing applications.
Test Configurations
- Flat-bottom: Single-chamber inflated floor, 32 cm beam
- V-hull: Inflatable V-shaped keel, 30 cm beam at waterline
- Tunnel-hull: Twin-tube configuration with central channel, 34 cm overall beam
Results
Drag at Cruising Speed (5 km/h)
| Hull Type | Total Drag (N) | Wave-Making Drag | Skin Friction | Best Use Case |
|---|---|---|---|---|
| Flat-bottom | 38.2 N | 12.1 N | 26.1 N | Recreational |
| V-hull | 32.5 N | 9.4 N | 23.1 N | Touring |
| Tunnel-hull | 35.8 N | 10.8 N | 25.0 N | Fishing |
Tracking (degrees deviation per 100 m)
| Hull Type | 3 km/h | 5 km/h | 7 km/h |
|---|---|---|---|
| Flat-bottom | 4.2° | 3.8° | 5.1° |
| V-hull | 2.1° | 1.8° | 2.5° |
| Tunnel-hull | 3.5° | 3.0° | 3.8° |
Conclusions
The V-hull design offers the best overall hydrodynamic efficiency with 15% less drag than flat-bottom designs at cruising speed. Tracking accuracy is significantly better (1.8° vs 3.8° deviation at 5 km/h). However, the V-hull requires more complex manufacturing with a dedicated inflatable keel chamber. For recreational use where speed is secondary to stability, the flat-bottom design remains viable.