“Onboard Security Systems”

By Frank Lanier
Chesapeake Bay Magazine 2003

While most folks envision Black Beard or Captain Kid when marina bar talk turns to piracy and other such acts of waterborne skullduggery, I think of Sissaro Phillips. Boogerman (as he was affectionately known) was experiencing a rash of break-ins at the store of his small marina / bait shack when I lived aboard there back in 1983. Best I remember the worst they did was steal beer and eat all the moon pies and microwave burritos, nonetheless they were a source of great botheration to ol’ Boogerman, who hit on a plan and after the fifth break-in. He put a hand written, cardboard sign in the window stating four nights out of the week he was waiting in the store with a shotgun full of rock salt and it was up the burglars to guess which nights they were.

Incidents of marina theft are is on the rise and while most of us can’t keep a shotgun-toting vigilante onboard, there are ways to make your vessel and its contents less tempting to thieves. Not too worried because you don’t own a multi-million dollar mega yacht? Think again. Professional thieves know these are most likely protected by sophisticated security systems – one reason boats in the 18 to 26 foot range are prime targets. They’re easier to steal, easier to disguise, and because there are literally thousands of them around, easier to dispose of without drawing attention. It isn’t just the professionals you have to worry about either, as large percentage of thefts are crimes of opportunity carried out by amateurs who just couldn’t pass up an easy mark. The good news is there are simple, commonsense precautions every boat owner can take to reduce their chances of becoming a victim.

To start with, never leave your keys onboard with the vessel unattended or worse yet, leave the engine running at the dock while making that quick run to the marina store. Why turn an “impulse shopping” incident into a potentially costly joy ride or worse. Contrary to what many boaters believe, simply removing the keys from the ignition and hiding them in the live bait well or hanging on the battery switch is not a viable anti-theft measure.

Avoid leaving your boat unlocked and open when unattended. If you have to make it accessible for maintenance or repair personnel, use a combination padlock that day. Give them the combination and change it afterwards. You should also change the combination every couple of months (if you use one full time) and always use case-hardened locks with a shield or some other form of protect against hacksaws and bolt cutters.

Lock ignition switches and consider installing a well hidden “kill switch” and fuel shut off or possibly remove critical parts such as the coil wire. If you rely solely on a fuel cut off, make sure it’s well hidden and as close to the engine as possible to reduce run time before shutting down (to keep a thief from abandoning your boat on the water because there was enough fuel in the lines to crank the engine and get away from the slip). When leaving small boats unattended for any length of time, consider removing the fuel line, portable fuel tank, or even the battery.

Take a walk in a thief’s shoes and case your own boat during the day and at night. Is it in dark section of the pier? If so, you may want to relocate to another slip or ask the marina manager about additional lighting. Close all curtains and keep equipment stored out of sight below decks, in locked compartments, or better yet in your garage or other secure area.

How hard would it be to break in to your boat? Can all doors and hatches be secured? Inspect securing hardware, as well as the hatches and doors themselves. Are they robust or flimsy to the point of absurdity, with shiny brass hardware secured by a few tiny wood screws. Now’s the time to replace broken hardware, beef things up, and replace screws with through-bolts and metal backing plates where possible, especially where hinge or hasp screws are exposed to the outside.

Are hatch hinge pins able to be removed from the outside? If so, make sure there’s a sufficient number of dogs to firmly secure it (at least two and preferably four). Sliding glass windows have a wimpy latch of some sort, but the best method of securing them is to place a wooden dowel in the channel behind the glass. Never leave hatches partially open with the boat unattended – you may let in more than a little air. If you’re not getting sufficient airflow with everything secured, install more vents.

It’s a good idea to record the HIN (Hull Identification Number) of your vessel and to engrave it on gear, electronics, or personal items you regularly carry onboard. For vessels without a HIN (they weren’t required prior to 1972) use your driver’s license or social security number. Make photos or videos of each item and create a master list of everything marked that includes make, model, and serial numbers where given. Keep a copy at home and on the vessel itself for quick reference.

Making sure you have adequate Insurance coverage is essential as well, however don’t view it as a substitute for proper security measures. You might get some new gear out of the deal, but considering the downsides (higher premiums, increased deductibles, down time, and aggravating paperwork) it’s best to prevent theft in the first place, especially considering that underwriters may cancel policies with a loss history.

Security System Basics

While commonsense anti-theft precautions can often be implemented at little or no expense, that new security system may also be less financially painful than you think. Many underwriters offer sizable discounts to boaters having acceptable systems installed, particularly when combined with fire and high bilge water alarms.

There’s a wide variety of security systems available, however many are simply repackaged home or auto alarms and generally inadequate for marine use. Marine units have to be more robust to survive not only the increased vibration inherent in boat installations, but the corrosive effects of a saltwater environment as well. Choosing one my seem a bit overwhelming, however the following basics will help.

A basis security system contains a control panel, a keypad, sensors, and some type of alarm (siren, strobe, etc.). Each component, in the right combination, works together to provide a comprehensive security and safety system for your vessel.


The brains of any security system is the control panel, which is comprised of one or more circuit boards housed within a single box normally large enough to accommodate a back-up battery, as well as wires for system input and output devices (sensors and alarms respectively). Control panels are required not only for arming and disarming the system, but to control and monitor all system security devices (motion sensors, glassbreak detectors, hatch contacts). When "armed," they help track events such as hatch openings and closing, movement within the protected spaces, power failures, and low battery conditions. They come in various zone configurations, usually 6, 8, or more depending on the number of sensors (each sensor should have its own zone if possible).

The keypad is how you communicate with the system, allowing you to arm or disarm it by entering a numeric code, check zone status, or add new users (some keypads allow multiple numeric codes to accommodate several users). It can also provide keyless entry, which not only eliminates the hassle of forgotten or misplaced keys, but also protects the vessel while providing limited access for maintenance or repair personnel (a hi-tech version of the combination lock method mentioned earlier).

Connectivity between control panel and components will be either a hardwire installation or through use of a wireless unit. Wireless systems are handy where wire installation would be a problem, however even these units require some wire runs (power, sirens, etc). Other disadvantages would be higher priced control panels and remote sensors, as well as the reoccurring cost of replacement batteries.


All systems have some form of sensors to detect an “event” (intrusion, fire, etc) ranging from motion detectors and magnetic switches, to a combination of different types. Some sensors detect specific sounds (glass breaking), while others detect movement or heat. As no one sensor works best in all situations, knowing the pros and cons of each will help tailor your security system for maximum effectiveness.

Motion detectors are highly effective and can simplify security system installation considerably, such as when one strategically placed motion detector protects an entire cabin (eliminating the need for sensors at each individual hatch or access). The best are “dual-tec” sensors, which typically combine infrared (passive heat detection) and microwave (active motion detection) technology into one unit. The infrared sensor detects radiant body heat and when triggered activates the microwave sensor, which then scans the space for motion. This two-pronged approach is not only highly reliable, but reduces false alarms, as both must concur before an alarm is generated.

If you have the option, stick with motion sensors that use K-band rather than X-band (the bandwidth frequency most dual sensors utilize). As K-band microwaves have higher frequencies and shorter wavelengths, they can’t easily penetrate bulkheads or glass, meaning the microwave is contained within the cabin, thereby reducing false alarms.

Magnetic switches consist of two parts, a magnet proximity switch and a magnet. An alarm is generated when the two halves are separated, meaning they can be used for hatches, doors, windows – pretty much anything that opens. An advantage of magnetic switches detection of intruders before they actually enter the vessel, however the down side is they can be circumvented if the thief breaks the glass of a hatch or door and gains entrance without opening them.

Photoelectric beams consist of a pair of “photo eyes” that emit a narrow, invisible beam between them that, when interrupted, generates an alarm. They’re easily hidden and can be installed to cover decks, access ways, bridges, and areas where installation of pressure mats or deck movement sensors wouldn’t be feasible. Disadvantages include significant power consumption and installation expense.

Glassbreak detectors come in two types – those that react to the frequency of breaking glass, and “shock sensor” types that attach to the glass itself. Of the first, the better ones actually listen for the flexing sound glass makes just before breaking and the audible sound during breakage (matching both helps to eliminate false alarms).

Deck sensors mount under a boat’s deck, while pressure mats are normally mounted above deck – both are triggered when an intruder steps on the protected portion of the deck. They’re highly effective when properly installed and maintained (pressure mats have the added benefit of no internal power consumption), however deck sensors are unfortunately difficult to install and maintain, while pressure mats are easily damaged by improper storage or sharp objects being dropped on them.

Finally, if despite the above precautions you become a victim of marine theft, report it to local law enforcement agencies, your insurance company, the marina manager, and the US Coast Guard (if the loss takes place on federal waters). I’ve also seen boaters post a list of stolen items at marina bulletin boards, marine chandleries, and local pawnshops (that’s were that master list comes in handy). Getting the word out and being able to positively identify your gear is crucial in not only recovery of your property, but the apprehension of the thief or thieves themselves.

As you can never make any vessel totally theft-proof, there is some truth to the old axiom about locks only keeping an honest man out. That being said, you can hopefully make it so difficult that the opportunity crook stays honest and the professional passes you by for easier pickings. So when you head down to buy those new locks, tell them Boogerman sent you.