Quiet energy

[rodtennyson]

For several years now I have heard the debate among sailors about using generators on their boats, especially the Honda 2000 generator which is affordable and can drive most of your boats energy needs like air conditioners, battery chargers and hot water. Many argue about gasoline storage, noise and the dangers of Carbon Monoxide (CO). Others like the convenience of energy on their boat beyond solar and wind especially in hot climates and lack of utilities for mooring and anchoring. I have never bought the "danger" issue of gasoline storage and CO because CO meters are readily available at low cost and we have been using gasoline on boats for a hundred years. We heard much of the same "safety" arguments many years ago about propane but we now use propane on our boats on a regular basis with little safety concerns. Solar and wind generators are expensive and you will never get these energy sources to run your A/C. A 3.5 to 4.2 KW diesel generator installed is always over $10,000 and takes up a lot of room and they do not guarantee the sound level when they run at 3000 RPM.

The real issue is noise both to your boat and to your neighbor's boat.

I wanted to use my Honda 2000 on my Catalina 375 sailboat to run its air conditioner, charge the house batteries, and make hot water but not all at the same time. The Honda 2000 has sufficient power to do these individual functions one at a time. The Honda 2000 is quiet but it is still too noisy for most people when running at full load sitting on your boat’s swim platform or fore deck. I designed an enclosed sound proof box for the Honda which used a specially designed wet exhaust system to dampen the exhaust noise and direct the wet exhaust to outside the hull just above the water line. The sound box was custom built into the starboard stern lazarette just above the diesel fuel tank, see attached picture. In addition to the wet exhaust cooling I installed two 3" inline blowers that were powered from the Honda 12V output plug. These blowers sucked hot air from the sound box out through the stern vents and to the open air.

The sound reduction was substantial producing the following sound tests. At anchor with no generator running the cockpit area showed general ambient background noise at 47db. Start the Honda, put under full A/C load, and leave the sound box lid off (Honda exposed to open air, with the meter next to the sound box) showed a reading of 68 db. Place the sound lid on the box and place the meter on the hatch lid, the reading was 53 db. Walk around the cockpit and the reading was 51-52 db. Sit out on the foredeck, and the reading was 48 db. Below decks in the salon with full A/C load the reading was 51 db, in the aft cabin 52 db and in the V-berth 49 db.

How you cool the Honda 2000 in its sound box is complicated engineering and the specs are are attached in a PDF format.
You can have quiet energy on your boat for reasonable cost and be safe.

Rod Tennyson
C-375 #16

[FlyingCloud1937]

What was the humidity in the gen enclosure, during extended run times?

Are you proposing to use fresh water from the tanks for the misting system, or sea water?

Have yo contemplated using heat recovery for the domestic hot water?

Lloyd

[rodtennyson]

Lloyd, All my tests were conducted in late June in Palm Beach County FL when the typical day time temperature is about 90F and about 85-90% humidity. Since the sound box cooling air takes in ambient outside air the humidity in the sound box is also 85-90%.

The cooling water for the Honda wet exhaust (all copper) muffler with the A/C running is sea water taken from a T joint on the A/C raw water output and partially diverted to the Honda wet exhaust. When charging batteries or making hot water I run a small (2.9 amp) centrifugal pump off a T joint from the engine shaft water bearing (sea water) to the Honda wet exhaust.

The mist cooling system is more a backup cooling for especially hot and humid days when the Honda and A/C compressor are running full bore for long periods of time. Once the A/C begins to cycle on and off I turn the mist off. I have a dedicated 5 gallon fresh water tank for the mist system.

Rod Tennyson
Lila Jean C-375

[zeehag]

adding mist here in 100percent humidityville could be an issue....how do you keep the humidity reduced in boat while this is ongoing on anchor situation.....

[Cotemar]

Can you post pictures of your Honda wet exhaust ?

[rodtennyson]

The mist cooling operates by mist spaying fresh water directly into the 150F hot air coming from the built in Honda cooling fan all inside the sound box. The mist immediately vaporizes in the hot air which is then sucked out by the inline blowers through the stern vent. The water vapor never gets inside the A/C or cabin but rather simply helps cool the inside of the sound box. The vaporization is complete because no fresh water accumulates inside the sound box where the mist is spayed regardless of the outside humidity.

[rodtennyson]

The Honda wet exhaust muffler was the most difficult part of this project due to the special brazing rods needed to fabricate the copper tubes to the Honda steel muffler at just the right hot spots on the Honda exhaust system. See attached pictures of Honda stock muffler and the modified wet exhaust. The large hose is the wet exhaust which connects to an exhaust hose leading outside the hull exiting about 8" above the waterline. The smaller hose is the intake raw water.

[onestepcsy37]

fwiw, we were once moored next to a big beneteau that had two honda 2000's on it's swim ladder, running all night to power it's air conditioner. we were maybe 80 feet from it and could not hear them running as we slept in our boat.

[FlyingCloud1937]

Originally Posted by rodtennyson

The Honda wet exhaust muffler was the most difficult part of this project due to the special brazing rods needed to fabricate the copper tubes to the Honda steel muffler at just the right hot spots on the Honda exhaust system. See attached pictures of Honda stock muffler and the modified wet exhaust. The large hose is the wet exhaust which connects to an exhaust hose leading outside the hull exiting about 8" above the waterline. The smaller hose is the intake raw water.

Now that is a future fire trap. The Steele muffler will rot out in short order from the salt water, and it will be double time do to the dissimilar metals. And if the generator ever back fires on shut down, it will most likely hydrological the motor.

You better keep vigilant eyes on the Hodge, before/after and during run times.

Lloyd

[colemj]

What I see is that he has coiled copper cooling tubes around the hot spots - not running water through the muffler itself. There should be no rot from sea water and no hydrolock from back siphoning.

Mark

[FlyingCloud1937]

Originally Posted by colemj

What I see is that he has coiled copper cooling tubes around the hot spots - not running water through the muffler itself. There should be no rot from sea water and no hydrolock from back siphoning.

Mark

You have to inject water into the the exhaust stream to cool it enough to send it overboard through a rubber hose.

It appears the injection is in the muffler. And the tubing is trying to cool the hot exhaust pipe prior to the muffler.

Maybe I need to see more pictures, but in any event I don't see this as being safe.

I also don't like to see the original gas tank in the same space. I would remove the tank and mount another tank outside the space.

Lloyd

Lloyd

[Cotemar]

Originally Posted by rodtennyson

The Honda wet exhaust muffler was the most difficult part of this project due to the special brazing rods needed to fabricate the copper tubes to the Honda steel muffler at just the right hot spots on the Honda exhaust system. See attached pictures of Honda stock muffler and the modified wet exhaust. The large hose is the wet exhaust which connects to an exhaust hose leading outside the hull exiting about 8" above the waterline. The smaller hose is the intake raw water.

Nice bit of engineering on that muffler. Is that silver brazing rod to take the higher heat.
I have seen cruisers rap copper tubing around motors on water makers also to remove heat. Works we'll and stands up to salt water well also.

[Cotemar]

Lloyd,
It's a heat exchanger. No salt water is leaving the copper tubing.
It's a very simple concept and most boat engines use it

[rodtennyson]

Lloyd, the wet muffler is a "simple" heat exchanger in which salt water never comes in contact with the steel muffler. The salt water never leaves the copper tubing and the salt water exits deep down into the lower end of the large rubber exhaust hose to prevent and back suction into the muffler. I installed a mixer at this point in the hose to mix up both water and exhaust for cooling and lower sound. The trick was the high content silver brazing (1000F melt) to make sure I had good metal to metal contact between steel and copper for good heat transfer.

As to the steel/copper dissimilar metals I have attached zincs to the muffler to protect for corrosion (not shown on the picture). I have been using this Honda on my boat for 3 years, 2 as stock and 1 year with the wet muffler with no signs of corrosion.

Unlike built in diesel generators at the end of the sailing season I just pull out the Honda (while by boat is in storage) re-install the stock muffler, do a thorough inspection and use the Honda for camping or power outages. If it needs repairs that I cannot do I just take it to the Honda dealer, much cheaper than marine diesel mechanics that have to come to your boat.

Rod

[Cotemar]

Rod,

I really like your Honda 2000 modification. The Honda 2000 is really only quiet when running a low wattage load. A full RPM load gets loud.

Thanks for sharing your idea. I hope others running high loads on a Honda 2000 follow your lead and make a modification like yours.