Your concept of using active paravanes ("gliders") to stabilize a slow-moving, solar-electric family trawler is highly innovative. By swapping traditional "flopper stoppers" (which only provide passive drag) for active hydrodynamic wings, you are entering the realm of advanced ride control. Below is an engineering and physics breakdown of your proposed system.
Are there underwater rated actuators? Yes. The ROV (Remotely Operated Vehicle) industry produces compact, waterproof actuators that are perfect for this.
You will need a specialized ROV tether. These cables feature a Kevlar or liquid-crystal polymer strength member core (capable of holding thousands of pounds of tension), surrounded by twisted copper pairs for power and RS-485/Ethernet data, all encased in a high-vis polyurethane waterproof jacket.
The biggest engineering hurdle for your design is your cruising speed. Hydrodynamic Lift is calculated using the square of the velocity (V2). At 4 knots (~2 m/s), water is passing over the wings quite slowly, meaning you need larger wings to generate significant force.
To stabilize a typical 35-40 ft family trawler weighing roughly 15,000 to 20,000 lbs, an outrigger paravane generally needs to generate vertically directed forces of 500 to 1,500 lbs (2,200 to 6,600 Newtons) to effectively counteract roll moments from waves.
The Math Check:
Lift = 0.5 × Water Density (1025 kg/m³) × Velocity² (4.2 m²/s²) × Area × Lift Coefficient (max ~1.0).
To generate 1,000 lbs (4,448 N) of downward force at 4 knots, each glider needs a wing surface area of approximately 2.0 square meters (21.5 sq ft). This means your "little airplanes" would actually have a wingspan of roughly 6 to 7 feet (2 meters) with a 1-foot chord. They would be relatively large pieces of gear to deploy and retrieve.
Because the gliders generate lift, they also generate induced drag. This is critical for a solar trawler where energy is a precious commodity.
| Component | Estimated Value |
|---|---|
| Speed | 4 Knots (2 m/s) |
| Drag per Glider | ~100 to 150 lbs (450 - 660 N) |
| Total Extra Trawler Power Required | 1.5 to 2.5 kiloWatts (continuous) |
Your proposed control loop is logically sound:
Because the glider is on the end of a rope, there will be a time delay. When the tail fin moves, the glider changes angle, generates lift, moves through the water, pulls the rope tight, and then pulls the boat. If this delay is too long, the boat may have already rolled the other way, meaning the glider might accidentally amplify the roll instead of damping it. The control software (likely a tuned PID controller) will need to be incredibly predictive to solve this phase lag.
Conceptually: Yes. Practically: It requires careful compromises.
The logic is sound, but the physics of 4 knots make the wings large and the energy cost high. However, if the control system acts swiftly, you might not need maximum pull at all times—meaning you can rely on short "bursts" of lift, reducing average drag.
Currently, to get zero-speed or low-speed stabilization, yachts use Gyroscopes (like Seakeeper, which use lots of electricity and are heavy but create zero drag) or Active Hull Fins (which work well at high speed, but poorly at 4 knots). Your system fills a unique gap: a deployable, high-leverage active system for slow speeds.
Your idea to prototype on an existing boat is the absolute right path. Here is how you can do it cheaply:
If you can prove that the active gliders reduce roll by 60-80% while only adding acceptable drag, you will have a highly marketable, patentable marine technology for the solar boating age.