Don't forget to turn that fire extinguisher upside down every now and then shake it and bang on the side of it with your hand. This loosens the powder so that it will flow properly when needed.
I know this is an older thread but I've been searching on some old posts and ran across this thread.
I don't really recommend people use Dry Chemical fire extinguishers on their boat (or aircraft) unless you're going to use it in an area that does not contain any electronics, as Dry Chemical is corrosive. I'm a product design engineer for
Amerex, we are one of the top global leaders in fire extinguisher manufacturing industry, and I've been in this industry for over a decade and I've seen some nasty fires in jets, offshore rigs, boats, houses, buildings, you name it. Many people choose dry chem because its cheap and its often what comes supplied with boats, jet skis, etc. The problem is its a royal pain in the butt to clean up as it's finer than baby powder and it gets airborne even in areas you didn't directly spray the agent. The rate of corrosion depends on many factors but if it were my property and boat, I'd rather fork out more money and carry a USCG Approved Halotron or Halon extinguisher. Yea they're more expensive but it's Clean Agent which means no residue and it's safe for use around electronics. This is what all people in the aviation industry use inside aircraft as they know that if you put out the fire, the last thing you want to do is to have some sort of corrosion issue on your electronics thousands of feet in the air months down the road that could have been overlooked on safety checks. Same for boats as you don't want something to go wrong tens, hundreds or even thousands of miles from help if you're offshore.
Not to mention, there's no need to bang or shake the Clean Agent extinguisher if it has sat to make sure you've "fluffed" the powder. Honestly you shouldn't need to fluff the powder if you have a quality dry chem extinguisher. We use a dry nitrogen and helium mix to fill most of our units as this ensures we don't have any moisture content from pressurized filling but unfortunately not all manufacturers fill extinguishers the same way. Also those who service their extinguishers may not be able to fill in a dry nitrogen application, so if that's the case they would bring in some level of moisture while filling. Most units I've seen in boats and jet skis are cheap units with plastic valve components and most are not refillable, let alone have any pressure gauge to indicate if you have a leaker or not. Never use an extinguisher with plastic parts and always try to use one with a gauge, if at all possible. Having one that is refillable like a true industrial level extinguisher is your best bet for ensuring you have a quality unit, that's serviceable and has a gauge for reading pressure.
If anyone has any questions about extinguishers or fire suppression systems, shoot me a PM and I'll be glad to help answer them. Just last week I had to help an older lady who was cutting grass on her riding lawnmower but as I drove past in my truck I saw the front of it blowing flames out. Normally I have extinguishers in my truck for emergencies like this but I had cleaned out my truck a week earlier and forgot to load them back in, otherwise I could have possibly saved her ole John Deere.
Here's an image of the Hand Portable Halotron I extinguishers we manufacture...
