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Routing Ducting for a Reverse Cycle AC Upgrade

Technical Articles

Tag: upgrades interior

There are no pre-engineered duct paths built into the C-320 contrary to some widely held beliefs. Some HVAC upgrades are very simple and minimize ducting and attendant carpentry associated with concealing the ducting. Others like the ones pictured here are more complex and involve a great deal of carpentry.



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Adding a Dedicated Starting Battery to the C-320

Technical Articles

My dedicated starting battery is sitting on a shelf that I added in the space just forward of the forward 4D in the starboard side settee. As a slight port list is typical for many C-320 owners and the space is ample for the purpose, this is a favorite location for many later model C-320 owners where the batteries are located under the middle of the starboard settee. This location is also desirable in keeping the new jumper wires short which reduces resistance and voltage losses.


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Flushing the Holding Tank

Technical Articles

Tag: head

For what it's worth, here is the recipe we've been using for flushing the holding tank for winter lay-up. We think it is very effective as the last flush is quite clear.

Holding Tank Recipe Ingredients: 
  2 c. Calgon Water Softener (liquid) 
  1 c. liquid laundry detergent 

Add two cups water softener in 1 gal. hot water. Pour/pump mixture into tank. Add one cup detergent to 1 gal. hot water. Pour/pump mixture into tank. Let sit for several hours then top off tank with fresh (hot if possible,) water and let sit for a few more hours. Even better is to sail with the tank full to thoroughly agitate the mixture in the tank. Pump out and rinse/pump with fresh water. 

Tip: Many RV stores carry a wand that attaches to a hose to provide a high pressure spray. Use this in the inspection port of the tank (if you have one) then rinse/pump again with fresh water. You may also be able to go in by removing the vent fitting on the top of the tank.

- Warren & Pattie Updike, Warr De Mar, #62

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Clogged Exhaust Elbow on Perkins M30

Technical Articles

If you happen to have a Perkins M30 diesel in your 320 and you idle the engine to charge your batteries, you risk building up carbon deposits in the cast iron exhaust elbow at the rear of the engine where the raw water mixes with the engine exhaust on its way to the water lift muffler. When this occurs, the symptoms typically include loss of engine rpm coupled with excessive amounts of thick black smoke caused by incomplete combustion of fuel since the engine can’t “breathe”. Removal of the elbow is pretty straight forward although the four nuts that secure it to the exhaust manifold can be a bit of a challenge. 

You could opt to clean and reinstall the elbow if it’s in otherwise good shape, however if it looks like the one pictured here you’ll have to spend the $350 or so for a new one. Either way after tackling this job you will probably find fewer reasons to idle your engine in the future.  

John Dean, Midnight Run, #227  


Yanmar Shifting Problems

Technical Articles

Tag: yanmar diagnostics transmission

Several C-320 IA members have been experiencing shifting difficulties with the KM2 transmission on the Yanmar 3GM engine. A marina neighbor experienced the same problem with the same engine in his Hunter 34, so we did some research on the problem. It didn’t take long to find numerous references on the internet including, sadly, some real horror stories about low time failures and expensive, non-warranty, repair bills.  This article steps through diagnosing and correcting these problems.


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What Color Is Your Exhaust?

Technical Articles


The color and quantity of exhaust smoke tells a great deal about the condition of a marine diesel engine. All marine engines create smoke to some extent, but if the diesel engine is in good condition, the quantity will almost be invisible. Defects that affect the fuel, breathing or compression will prevent correct combustion and lead to excessive exhaust smoke.

The following analysis comes from U.S. Master Marine Surveyor Rob Scanlan and is presented courtesy of RCR Yachts.

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Steering Cable Failure

A failure of the steering cable was reported by Ken Danko on hull 802 on 12 October 2008. Conditions at the time were choppy seas and 25 kt winds. Ken's assessment and photos are captured below, along with responses by Gerry Douglas (Catalina Yachts) and Ed Siess (Edson).

At the end is additional thoughts and learnings from Ken and a reaction to the information provided by Edson.

My suggestion would be immediate inspection of your steering cable and rudder stops, looking especially for wear in the same area as Ken's failure (recognize that cable wear has also been reported at the chain link end inside the pedestal). Follow up with annual cable and stop inspections.

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