Inspiration Board · EvoMarine

Why

Horizon

The living world already knows how to move through the ocean. EvoMarine builds from that.

Evolution spent ages refining bodies that travel far on little effort. We take those forms as teachers, and steady them with a control computer, so a craft can stay longer, quieter, and closer to the life it observes.

01

Active stability

Founder note · F-16

The F-16 is built to be agile. It behaves more like a dart than a glider. A human cannot hold a precise path without the flight control computer. The computer makes that open design space flyable.

The move

EvoMarine puts a dedicated control computer on the craft so it can hold still and move slowly near marine life without thrashing the scene.

Stability lives in software. Fast sensing and a dedicated computer free the hull to stay efficient and quiet.

Airframe held by the loop

Relaxed static stability made the airframe agile · the flight control computer made it flyable.

USAF · public domain via Wikimedia Commons

Side-stick

Small stick inputs · the computer scales how hard the surfaces move.

Public domain via Wikimedia Commons

Fly-by-wire path

Sensors and computers close the loop · surfaces follow the computer.

EvoForm diagram

Plan view

Shape for performance · the computer keeps it flying true.

Public domain · Wikimedia Commons

Why the F-16 control system matters

Relaxed static stability	Airframe built to respond fast · the computer steadies it all the time.
Full fly-by-wire	Surfaces driven by the flight computer · pilot sets rate and g demand.
Four-way backup	Four independent channels · still works if one fails.
Fast sensing	Accelerometers, rate gyros, air data · continuous correction.

Air to water

Air · F-16	Water · EvoMarine
Agile airframe · multi-axis rates · fly-by-wire	Hull that is easy to tip at slow hold · computer steadies it
Rate and g demand from the stick	Quiet hover and slow transit as the outer goals
Flight control computer	Underwater control computer · attitude, depth, optional speed-over-ground

How control builds

Hold attitude and depth well with solid sensing of where the vehicle is
Then hold place · stay put quietly before long runs
Smarter control later if the simple loops are not enough · still on the vehicle, still real time

Two computers

A small stability computer · separate from the science payload computer. Lessons from fly-by-wire, drones, and research AUVs.

02

What drones prove

Everyday multirotor · open flight stacks

A typical multirotor is not passively stable. Tip it and it wants to keep tipping. Four independent motors, coupled axes, fast dynamics. No human can juggle thrust on each prop in real time the way the vehicle needs.

Multirotor in flight

Everyday unstable airframe · held by a flight controller.

Wikimedia Commons · public media

Flight controller board

Light stability computer · IMU + high-rate loop · consumer weight.

Pixhawk-class · Wikimedia Commons

Layered stack

Inner: attitude · Middle: velocity/position · Outer: “go there / hold here.”

EvoForm diagram

A multirotor tips and keeps tipping without the loop. The pilot never balances four motors. The pilot commands intent. The same layered idea, tuned for water, is how EvoMarine holds quietly.

Combat fly-by-wire is heavy by design. Drone controllers are light because the job allows it. Open stacks already prove the pattern at everyday weight.

Layer transfer

Layer	Air drone	EvoMarine
Inner	Attitude rate / attitude	Attitude + depth
Middle	Velocity / position	Station-keep / slow track
Outer	Waypoint / “go there”	“Hold here quietly”
Sensors	IMU, baro, GPS	IMU, depth, optional DVL

Why this is buildable now

Drones prove layered control at low weight. Research AUVs prove depth and attitude hold underwater. Leatherback studies give hull and coasting cues with a paper trail. Prototype 1 joins those for quiet observation over hours.

03

Leatherback sea turtle

Evolution already solved long-range efficiency, pressure-tolerant volume, continuous skin, ridge lines, and flipper-style drive at large size. We take those ideas into a made platform. Resemblance follows performance.

Rear shape

Keels, trailing edge, flippers · teachers for control surfaces.

Adult scale

~3 m class animal as a size teacher · re-size for the platform we build.

At the surface

Long body, ridge line, quiet outline in open water.

Footage courtesy David Currie · Instagram @dcurrie_drones

Mass and presence

First builds may be heavy · batteries, insulation, electronics, robotics. Boat or crane is fine. Refine and shrink later.

Ridges and flow

Ridges may help flow when sized to our speed. We test before we claim it.

Speed class

Animal burst is one reference · we aim for survey and hover (~1–2 m/s transit).

Later · deeper work

Shell mosaic and flexible volume are later studies · small material coupons first. The first quiet hull stays a simple continuous skin in upper water.

Study media only · not first-build scope

04

Architecture

Hull	Leatherback proportions · ridge cues with real flow basis
Volume	Room for battery, two computers, buoyancy, insulation, robotics, and sensors · bigger first builds are fine · shrink after we learn
Motion	Short thrust, long coast · turtle pattern in lab work is about 30% effort and 70% glide
How it moves	Buoyancy for depth · trim mass for pitch · light thrust and a few control surfaces
Skin	One continuous outer skin · ridges that do a real job

A craft that stays calm in its shape and spends energy in short, careful bursts.

05

First prototype

Quieter hold. Longer presence. Deploy that matches the real weight.

1 · Control computer · hold attitude and depth · light thruster use · log noise and power in the tank
2 · Leatherback-shaped hull · ridges that do a job · continuous outer skin
3 · Hydrophone first · layout and mounts early
4 · Buoyancy hover · less thruster so listening leads · long coast in transit
5 · Clean exit · leave the scene cleanly when it is time

Quiet first Heavy first build Boat or crane 0–50 m first Sensors over speed Computer holds stability Hydrophone + camera

Sequence

Now · Quiet upper water · continuous skin · light thrust and buoyancy hover · hydrophone first · tank baselines
Next · Better efficiency only if sized right · catch-up transit · camera that turns while the body holds
Later · Deeper work · flexible volume under continuous skin · study toward 200 m+

06

Prior work

Ridges · lift and drag

Published glider studies · ridges can improve lift-to-drag at a low angle of attack.

Paper class · redrawn chart · size ridges to our speed before claiming a drag win

Stroke and glide

Lab animal work · effort in a smaller part of the cycle · mass and low drag carry the coast.

Lab biomechanics · long coast means less thruster wash while we watch

Hold by buoyancy and control

Pitch and depth held with buoyancy, moving mass, and an onboard computer.

NOAA SeaBED AUV Popoki · public domain

Hull sized for real energy and payload · buoyancy and light thrust · sensors first.

Trial one · what success looks like

Multi-hour smooth depth and attitude hold · calm transit with long coast · sensors usable the whole time. Exact depth band and hours lock with scale.

07

Open

Still open

Length and weight for prototype 1. How many fins. Which sensors for the stability loop. Shallow-trial depth and hours. Shape stays open until scale and fins lock.