Ask The Experts

Solutions from the BoatUS Tech Team

The Burning Question

I have flares that expired in 1997, but still appear to be in good condition and undamaged. What should I do with them?

Don Casey: There's no universal answer. You can just keep them aboard — separately packaged and marked EXPIRED — where they could be useful in a real emergency. Most flares function perfectly years beyond the expiration date. In some places, the local fire department will welcome them for training or just disposal. Some public-sanitation departments will accept flares during special "hazardous materials" pickups or drop-offs. Some boaters fire off old flares on the Fourth of July or some other fireworks holiday, but while you might get away with this, I am confident that it remains illegal. I've always been able to convince my local firefighters to take them.

Hot Water Smell

What's the best way to clean a hot-water heater and get rid of the odor?

Tom Neale: Your water heater probably has an anode that helps to protect metal parts of the tank exposed to water. If you haven't changed your anode annually, some of its sacrificed material may be at the bottom of the tank contributing to the odor. Also, boat water tanks, lines, and hot-water heaters sometimes grow organic material over time, even if you have a good source of potable water. This can cause odor, particularly at the bottom of the hot-water tank. Check the filter protecting your fresh-water pump. If you see "stuff" in it that looks vegetative, you can be fairly sure that this is part of the problem. Try the following:

1. Completely depower the unit at the circuit panel to be safe. Make sure there are no hot wires, AC or DC, near your working area. Turn on the hot water and let run until no more hot water comes out of your tank. Let the tank cool. Turn off your fresh-water pump or disconnect pressure from shore water. Open the hot-water spigot again to be sure there's no tank pressure remaining. Be prepared to dump a lot of water into your bilge.

2. Disconnect the external fitting(s) that is connected to the hot-water (out) nipple and the cold-water inlet. This is a good time to add a T and valve in your cold-water line, with a drain line to the bilge, so you can drain the tank in the future without making a mess.

3. Remove the hot-water fitting at the top; this has the anode connected.

4. Using a garden hose connected to the hot-water nipple, apply water pressure directly into the tank and let it drain out of the bottom cold-water fitting until the solid anode material and all the other junk that's settled to the bottom are rinsed out of the tank.

5. Replace anode and reconnect the other fittings.

Follow the same procedure if you don't have an anode. If you don't, and particularly if your tank is metal, check carefully for signs of leakage. Even stainless tanks can have a problem because of the welding and composition of the welding material. Pinholes and leaks can develop here.

Many companies, such as Star brite (, offer products designed to remove odors in boat tanks, and you might check out these after you've done the cleaning. If you still experience smell from the hot water, it may be coming from other stuff in your main tank and plumbing, which may need to be cleaned.

How Smart?

I'd like to replace the alternator on our Yanmar 3GMD with an externally regulated alternator and a multi-stage regulator. The rule of thumb says an alternator should be hot-rated for 25 percent of your battery bank size, plus any loads that run while the engine is running. But if the alternator's hot-rating is twice the battery bank's maximum charge acceptance rate, can the battery bank be damaged when using either a single-stage or multi-stage regulator? We have a relatively small battery bank (130 Ah), and many of the popular externally regulated alternators seem to have a greater output.

Don Casey: The reason to abandon the Yanmar alternator is to gain the benefit of a smarter regulator. A three-stage regulator is going to deliver maximum output current until it drives the battery voltage up to a predetermined level — typically around 14.4 volts for a wet-cell battery. After that, it switches into an "absorption" stage, holding the output voltage constant. This stage is more or less identical to what a single-stage regulator like the one integral to the existing alternator does. The third stage of the smart regulator comes into play when the battery is fully charged. In this final stage, the regulator limits the charge voltage to something that will not subject the battery to overcharging.

A single-stage regulator with the correct set point will not damage the battery no matter how large the alternator unless you run the engine continuously for many, many hours. Likewise, if a smart regulator functions correctly, it should protect the battery from the potential damage from a high-output alternator, with the added plus of eventually cutting the charge voltage back to a safer "float" level.

What the 25-percent rule is really about is wasting money. A wet-cell battery shouldn't be charged at more than around 25 percent of its amp-hour capacity, so for your 130-Ah battery, a 35- to 50-amp alternator delivers all of the power the battery can accept. If you fit a 130-amp alternator, the smart regulator may allow overcharging for a short period of time (not particularly good for the battery) and the high amperage is going to drive the voltage up more quickly so that the regulator switches into absorption at a lower actual charge level — sort of a double whammy. Once the regulator switches out of the bulk charge stage, you are getting exactly the same charge profile that you got before spending the money on fast-charging equipment. The float feature is worthwhile if you motor a lot, but otherwise it, too, is a waste. Big alternators and smart regulators are great when paired with a big battery bank and typical cruising boat power consumption, but this "upgrade" really isn't if your electrical system cannot take full advantage of the extra capacity.

Keeping Ahead Of The Hose

We just changed the line going from our head to the holding tank. It was totally built up. Is there anything we can put down the toilet to keep this from happening again?

Tom Neale: There are several products like Raritan's CH. (CH stands for Cleans Hoses.) It's made specifically for this problem and is a relatively new product. It's not cheap, but in my opinion, it's worth it. See my discussion on:

Hardware Store GFCI?

I need to replace the Ground Fault Circuit Interrupter (GFCI) on my cruiser. Will a hardware store GFCI be ok, or are there special marine models of GFCIs?

John Adey: Good news. A household GFCI is fine as long as you consider ignition protection. The GFCI off the shelf is not ignition-protected, meaning it's capable of producing a spark that may ignite gasoline fumes. So if the GFCI is in a gasoline engine space or a space with fuel lines, tanks, or fuel line fittings, install the GFCI outside the space and "daisy chain" it to a standard outlet downstream in the space. If you're using an inverter with the GFCI outlet, check the owner's manual. Many inverters have specific manufacturer part numbers for the GFCI due to the sine-wave produced; not using a specified unit may result in nuisance tripping.

Other considerations are the connections. Don't use the push-in connector on the outlet! Use a captive terminal (such as a ring terminal) on the screws on the side of the outlet. Stranded wire isn't made for those push-in connections.

Photo of replacing the Ground Fault Circuit Interrupter (GFCI)

Emergency Pump

I'm getting ready to install a 3-way valve between the strainer and raw-water pump on the engine. I've seen this before as a secondary bilge pump when in an emergency situation. Can you offer guidance on what, if any, particular valve to use? Should any other changes be made to the cooling system and/or exhaust?

Don Casey: I'm not a fan of this idea. A typical raw-water pump can push about 10 gallons per hour, per horsepower. If you have a 50-hp engine, the cheapest ($20) electric bilge pump can match this capacity. Using the raw-water pump as an emergency pump exposes it to unnecessary and ill-timed risk. Anything that stops the flow of water to this sensitive pump will destroy it, shutting down the engine just when you may be in greatest need. Things that will ruin the pump are: closing the thru-hull before opening the bilge intake, sucking up debris from the bilge, or just sucking air via the bilge pickup. Also, if your plumbing to the bilge pickup, including the valve, isn't 100-percent airtight, it can cause the pump to lose prime at any time, potentially causing expensive engine damage.

A better strategy is to install an additional electric pump as large as you can find room for. You can activate this pump with the flip of a switch, not by crawling into the engine space to throw the handles on (probably underwater) plumbing valves. As long as the engine runs — more assured with an unaltered connection to the seacock — and as long as your batteries remain above water, this pump will expel water at a rate many times higher than the cooling pump could have. If you want the added capacity of an engine-driven emergency pump, it should be a belt-driven add-on with a clutch, not the small-capacity pump your engine depends on to keep running.

Tripping Question

I know of two different boats where leaving the blower on for long periods (20 minutes) will blow a breaker or a fuse. Is it normal for the fuse to blow, or breaker to trip when used for more than just startup?

John Adey: No, it's not normal. The breaker or fuse will trip with excessive amperage draw, so we need to find the source. Assuming there's no junk (bird nest perhaps) in the blower system, let's first look at the wire. Is it appropriately sized for the draw? A 5-amp motor, for instance, sized for a 3-percent voltage drop (required for blowers) at 7.5 feet from the switch requires a 16-AWG wire. How about the connections and the integrity of the wire? Are the connections clean and properly crimped?

Is the blower in a very hot area too close to the engine perhaps? Could the heat cause parts to expand and create friction, causing resistance and the breaker to blow? Perhaps move it farther out of the engine space along the hose run.

Another possibility is that some blower motors aren't designed to run for long periods of time and will heat and develop resistance, thus causing a circuit-breaker trip. Also, as they age, bearings or bushings may wear, resulting in increasing resistance and circuit breaker tripping.

Cuddly Cuddy Cabin

I have a 1987 Spacecraft cuddy cabin. The carpeting on the ceiling in the cabin is coming down. What type of glue or cement do you recommend to reattach it?

Tom Neale: If your carpeting is in good shape, there are two methods that may work. One is spray adhesive, the other is a hot-glue gun. I have used the spray adhesive for the same purpose in cars, and found that it works for a while, then usually falls down. The trick is to coat both surfaces entirely, and then hold the carpet in place while it sets. You'll need help. I personally haven't used a hot-glue gun, but the principle seems good, and people with lots of experience in boat work have reported using it for a number of similar applications.

If there's a lot of sticky glue on both surfaces now, you may want to replace the carpet and remove the glue from the underside of the cabin top before you proceed. What you'd use to remove it would depend on what the glue is. Things to try are alcohol or acetone, but always with plenty of ventilation. These also are often flammable and/or explosive, so heed the warnings.

The best solution may be to remove the carpet altogether, clean up the ceiling, and simply paint it. There are also other materials that you may wish to investigate. For example, we recently covered part of the interior of our boat with sheets of Komatex. See my article at Information on sprays and hot glues can be found, for example, at:, and


I have a 1987 Bayliner with a halon fire suppression system. I don't want to change over to the new system. What can I do to keep from installing a new replacement system?

John Adey: The EPA has banned the manufacture of halon but not the use of it. If the cylinder weight is correct and an inspection shows the hardware to be in good condition, then you're fine keeping it on your boat. The USCG has pulled approval on new systems with recycled halon, but since they don't require an automatic, clean-agent system on recreational boats, you can satisfy USCG requirements by having aboard the required portable extinguishers. Most manufacturers will suggest that you switch to a new FM200 system, as the halon system is probably 20 years old, but it remains legal with the halon cylinder(s). I've also heard of halon recyclers. Check out My understanding is that there is halon available, and if you can find a dealer to do it, it's perfectly legal to get your system recharged. 

— Published: February/March 2012

Meet The Experts

Photo of Don Casey

Don Casey
He's been one of the most consulted experts on boat care and upgrades for 30 years, and a panelist on our "Ask The Experts" website for a decade. He and his wife cruise aboard their 30-footer part of the year in the eastern Caribbean. His books include Don Casey's Complete Illustrated Sailboat Maintenance Manual, and the recently updated This Old Boat, the bible for do-it-yourself boaters.

Photo of John Adely

John Adey
The VP/Technical Director for the American Boat & Yacht Council (ABYC ), John grew up boating. He's been in the industry since 1990, with experience from a yacht brokerage and boatyard to owning a marine supply store. He and his family sail their classic 1976 Irwin ketch, a boat he completely restored. John is a trusted source for technical information for industry professionals.

Photo of Tom neale

Tom Neale
He's maintained, lived aboard, and cruised long distance on boats with his wife and family for most of his adult life. He can take apart and fix almost every system aboard a boat, has written two books, filmed a two-set DVD on East Coast cruising, written for top marine magazines, and has won seven first-place awards from Boating Writers International and many awards for his technical writing.

Photo of Bob Andriance

Bob Adriance
The editor of Seaworthy, the damage avoidance newsletter of BoatUS Marine Insurance, Bob has written hundreds of articles on safety, loss prevention and causes of boating accidents. His 2006 book, Seaworthy, Essential Lessons of Things Gone Wrong, is based on 20 years of real claims files. He's owned Folkboats to J-Boats and currently sails a 36-foot sloop.

Photo of Lenny Rudow

Lenny Rudow
One of the most experienced technical writers in the marine business, and an accomplished fisherman, Lenny has a thorough understanding of modern marine electronics on both technical and end-user's levels. He's written five books, and won 18 Boating Writers awards and two awards for excellence from the Outdoor Writers Association. For several years running, he's also been selected as a judge for the NMMA Innovation Awards.


BoatUS Magazine Is A Benefit Of BoatUS Membership

Membership Also Provides:

  • Subscription to the print version of BoatUS Magazine
  • 4% back on purchases from West Marine stores or online at
  • Discounts on fuel, transient slips, repairs and more at over 1,000 businesses
  • Deals on cruises, charters, car rentals, hotel stays and more ...
  • All For Only $24 A Year!

Join Today!