Boat Security Systems: How to Prevent Marine Theft Before It Happens

From Victim to Innovation

By Tony Cantrill

I did not start out to build a marine security system. I set out to buy one.

I have been a software engineer for 38 years. My background is IT. Systems architecture. Logic. Problem solving. Risk modelling. The sort of work where you identify failure points and design them out. Marine security was never part of the plan.

Then my boat was stolen.

It disappeared in July. Flat calm. High tide at midnight. No moon. No nav lights. No torches. No ignition. They towed it straight off its mooring. CCTV showed nothing more than headlights sweeping the bay before and after. In between, it simply vanished.

The first reaction from people around me was disbelief. “Nobody steals boats.” “It must have drifted.” “How do you know it was stolen?”

The reality was harder. That season alone, between the Isle of Wight and Land’s End, eight boats were taken. Most people never heard about them. They are rarely publicised. The statistics are buried inside broader theft data. Outboards and boats are not always categorised separately. Awareness is low. Complacency is high.

That gap between perception and reality is where SeaSight began.

Searching for a Solution

After the theft, I went looking for a solution. I assumed something comprehensive already existed.

I wanted instant alert if the boat moved. I wanted to know exactly where it went. I wanted to be able to sound a siren. I wanted the option to immobilise the engine. I wanted it to survive power removal. I wanted something designed for marine conditions, not a car tracker bolted into a console.

Nothing ticked all the boxes.

So I built it.

It took over six months of design and testing. We trialled different architectures. We initially pursued a fully integrated patent route but pivoted to a modular system when it became clear that flexibility would deliver better real-world resilience. We tested in storms. We tested in heavy chop. I was out in 26-knot winds in a tender running wave simulations because automotive logic simply does not translate to a boat bouncing on a mooring.

Cars do not move in car parks. Boats move constantly. That difference matters.

SeaSight Secure – The First Layer

The first layer is visible deterrence.

SeaSight Secure is designed to slow down opportunists and signal protection. It is a physical barrier, but it is engineered to work within harbour byelaws. Many harbour authorities incorrectly assume that locking a boat breaches regulations. The rules relate to obstructing navigation channels, not preventing theft.

Our system works like a TSA-style release. Authorised harbourmasters or named keyholders can unlock it if required. It ticks the deterrent box without creating compliance issues.

You cannot measure how many thefts are prevented, but you can increase friction. That matters.

SeaSight Shield – Active Marine Monitoring

Shield is the operational core.

It is hard-wired into the vessel with its own battery backup. It includes:

Real-time movement alertsGeofencingTow detectionBattery monitoringSiren activationEngine immobilisationFull tracking across 135+ countries

It is tuned specifically for marine behaviour. It knows when the boat is on its mooring. It knows when ignition is live. It differentiates between storm movement and unauthorised relocation. Automotive trackers cannot do that reliably because they are not built for wave motion and constant oscillation.

Shield also uses a two-part mooring sensor system. A small floating module — smaller than a tennis ball — sits on the mooring. The boat unit recognises connection status. If separation occurs, you are alerted immediately .

That sensor can also be used creatively. On a quay. On temporary berths. It provides situational flexibility.

SeaSight Stealth – The Hidden Layer

Thieves cut power first. Sometimes they cut engines off entirely.

Stealth is a fully self-contained battery module. No reliance on vessel power. No visible presence. It can sit hidden for over three years on internal battery alone. It is IP68 rated. It pings its position every 24 hours or instantly when movement is detected.

The Stealth unit can be hidden any where on the boat or in the high value assets. eg tender , engine cowl, or water toy.

Stealth is designed for jet skis, wooden sailboats, tenders and any vessel without reliable onboard power. It is the insurance layer when everything else has been compromised.

Global Monitoring

The subscription is not a control centre taking over your boat. Owners access everything through the app.

The cost exists because of global IoT connectivity. The GSM connection links across 135 countries. There is a global communication infrastructure behind it. That ongoing connectivity carries a subscription cost .

You are paying for live communication, encrypted data transmission, firmware updates and system health monitoring. Without that, it is just hardware.

Security is a service, not a one-off device.

Early Days, Real Intent

We officially launched in July — the anniversary of the theft. Although we have not yet completed a full season cycle, the industry is waking up to the reality and cost of boat thefts across the globe as we continue to shine a spotlight on a real problem.

The real challenge is not technology. It is mindset.

I have had conversations where one partner sees the risk clearly and the other says, “Nobody is going to steal this boat.” I have heard yacht club members insist it does not happen. Yet engines are removed overnight. RIBs disappear. Support boats are towed out in darkness without lights.

The problem is not rare. It is under-recognised.  

Continuous Development

We are currently enhancing winter mode functionality. Many owners remove batteries over winter storage. Shield will soon be able to enter deep sleep and behave like Stealth for up to six months, extending resilience when primary power is disconnected.

Layered protection remains the philosophy. Visible deterrence. Immediate alert. Active immobilisation. Independent backup tracking.

I built SeaSight because I experienced what happens when those layers do not exist. My background in software engineering meant I approached the problem systematically. Identify the failure points. Design around real-world behaviour. Build for the environment, not the brochure.

The objective is simple.

Move the moment of awareness forward.Increase friction for thieves.Give owners control before a vessel disappears.

Seasight have a security solution for every boat. See the website for full the full range: https://www.seasight.world