Burglar alarm

[Bradley]

Does anybody have information about a good burglar alarm for my boat.. I had an old alarm system built into the fog alarm, but it seems to have gone on the blink. A web search for the mfr. did not yield any results.

I don't need anything fancy. Just a good dependable system with a loud siren.

[Southern Star]

Bradley, I too am interested in installing one on my boat. The marine systems are incredibly expensive, so I have been thinking of creating my own using automotive door light switches connected to a horn/the deck floods, with a hidden activation switch. Obviously corrosion could be an issue, but there are some covered with rubber boots.

Brad

Brad

[Hud3]

Some cruisers use those motion detectors that Radio Shack sells. $30 bucks or so, if I remember correctly. Some have even talked about hooking them up to a tape player with a tape of a viscious dog barking!

[Southern Star]

The problem with motion detectors is that they are constantly using current and, from what I have seen, are typically 120 volt. I am principly interested in protecting the companionway door and any hatches large enough to permit human entry.

Brad

[Hud3]

Brad,

This one's battery operated. $26.99. It would be useful if someone tries to get in while you're on the boat, but not loud enough to attract a crowd.

RadioShack.com - Home & Office: Home security & safety: Personal safety: Portable Motion Detector Alarm/Chime

[GordMay]

12 VDC Motion Detectors (Passive InfraRed) are available, which use between 100mA to 400mA (0.1Amp to 0.4 A, standby) current.

Infrared Motion Sensor - 12 volt 10 amp
10-14V PIR Motion Detector Module (3133)

MOTION DETECTOR ACTIVATED LIGHT

[Holding Pattern]

The PO's put a switch-type alarm system onboard for their circumnavigation (never had to use it but that is beside the point.) The switch is connected to both the onboard alarm (red fire bell that tells us of any low levels, etc.) and to the deck lights, main and mizzen spreaders. We have accidentaly hit it while goofing off and brought several boats from the anchorage to see if everything was okay.

I have talked to a few who have the motion sensor type alarms and have complained of birds, debris, and sometimes phantoms setting off the sensor and a very rude awakening to shoo away a sparrow.

We've also heard other things...we have lifeline netting up for the cats' sake...but those in the know have told us that potential burgulars assume dogs or children and wanting to encounter neither, you become a less likely target... now, that may be a tiger charm, but...

[EatDrinkHealthy]

You can use a magnetic reed switch for house hold alarms. One side is a small magnet and the other side is an enclosed reed switch. When the magnet is very close the reed switch is open thus draws no current. You can sound any alarm you like. I found one that you can drill a small hole and epoxy inside the companionway board. The reed switch is glued to the side and hook up to a switch and 12V horn. Normally draws no current.

[Southern Star]

Thanks Hud, I checked out these units but they are simply not loud enough (and indeed, the one review refers to the chime setting as being louder than the alarm). And Gord, thanks - the unit in your posted link may be worth checking out. On the other hand, I still think that automotive door jamb courtesy light switches with rubber boots would be easy to install and less likely to send off false alarms. The parts are pretty cheap, so unless anything else comes up, I may just experiment when I get the time.

And Holding Pattern, the netting idea is interesting (assuming the thieves in cruising destinations know enough to realize what they are for).

Brad

Brad

[donradcliffe]

If you are living aboard, a simple self-contained IR alarm/chime is enough to make sure that no one gets aboard or takes your dinghy undetected. They are battery operated and the batteries last at least half a year. I wandered thru Radio Shack the other day, and now see that they have wireless remote sensors, so you can monitor more than one area.

I get the occasional false alarm, especially when the sun hits them in the morning, but they have also gone off for real, like at 0130 in the Solomon Islands.

I also installed a switch operated system (12v, designed for motorhomes) which flashes the spreader lights and has a siren through the cockpit speakers, but its been a lot of trouble to maintain.--its easier to get acquainted with your neighbors, and let them watch the boat.

[Southern Star]

Eatdrinkhealthy, do you have a source for the magnetic reed switches? I had assumed that ones designed for 120 volt household systems would not work on 12 volt systems, especially with some exposure to the elements. And Donrad, what were the specific maintenance problems with the switch operated system (and what type of switches were utilized)?

Brad

[dacust]

Originally Posted by Southern Star

Eatdrinkhealthy, do you have a source for the magnetic reed switches? I had assumed that ones designed for 120 volt household systems would not work on 12 volt systems, especially with some exposure to the elements. And Donrad, what were the specific maintenance problems with the switch operated system (and what type of switches were utilized)?

Brad

The 110v systems don't run 110v through the switches. They run something like 6v or 9v? Don't remember. I'd double check the requirements for whatever system you get, but I bet the standard switches will work with any system.

Note: most alarms use normally closed switches that are open with the magnet, which draw no current when the door is closed. But they also sell identical looking normally closed switches that are the opposite. If you want a system to draw minimal current, make sure your alarm system will handle the normally closed ones before you buy. However, the small amount of current that the loop takes may not be the deciding factor. You should look at the operating current the system specifies. I'm sure there are some normally open systems that take much more than some normally closed ones.

Note the confusing mis-match of how I use "normally open/closed". I think I have it right, but someone please correct me if I am wrong. A normally open system is at it's normal operating state when the circuit is open (in this case, when the magnet is holding the switch open), but a normally closed switch is one that is closed when no outside force is acting upon it. So, a normally open alarm system would use normally closed switches.

Oh, and the switches are sealed. You just need to take care to protect the connections.

-dan

[Southern Star]

Thanks Dan - Flagship Marine sells a 12 volt security system with magnetic door switches but has optional 'exterior' wide gap switches (@ 19.95 each) that are recommended for exterior locations. This leads me to believe that the standard magnetic reed switches aren't really waterproof. The standard ones do appear identical to the ones used in house alarms, however, so I suspect that the voltage won't be a problem.

Brad

[Therapy]

The ones I see are about 5 bucks.

Lots of choices. Reed Switch Magnetic On GlobalSpec


Could one simply take a household one and cover with shrink wrap?

[Roy M]

Radio Shack used to sell some home security systems, but have switched away from these units to another type. These were 12 volt units, with an AC charger/supply. I used to install them in beach houses in Mexico, so I became quite familiar with them. It's possible a few may be available on E-bay. I'll try to find the model number in my records. Modern security systems often operate the same, on 12 volt DC.

Without revealing too much of my own security systems, I can say the following:

Most systems have programmable, multi-zone alarm setups. This allows you to go to bed, setting the "HOME" mode. If someone boards your boat silently, opens a locker, or attempts to remove something on deck, the act triggers a sequence of events. At night, the deck lights come on, along with an ear-shattering alarm from the spreaders. It can also trigger a video recorder to gather evidence. You are still free to get up in the middle of the night, open your hatch and wander about the deck, unless you have previously installed local pressure sensor mats or short range motion detectors. When you leave the boat, secured, all of the above, plus opening of hatches sets off the same sequences. In addition, you can have certain zones that are armed 24/7, so if a curious crew or workman wants to explore, they will inadvertently notify the universe of their adventure.

These can be wired into the boat's main bank, or have a covert power supply, since they use milliamps when in the monitoring mode. It's only when the alarms go off that any appreciable drain occurs. Further, by the use of simple Radio Shack relays, you can power more current to auxiliary devices during an intrusion incident.

Arming of the system can be done with a key, a hidden switch, or a keypad, or any of the above. You can mount "panic" switches next to the bunk to turn on the deck lights, or announce the second coming, should you hear a strange bump in the night.

This stuff is really simple to install, uses virtually no juice, costs very little in comparison to the investment that is being secured, and it makes you feel better at night or leaving the boat.