CD36 AUTOPILOT & REFRIGERATION UNITS

[CHARLIE PALUMBO]

HELLO FELLOW CD OWNERS,
ALTHOUGH OWNING MY CD36 FOR 14 YEARS, I THINK IT IS TIME FOR A RELIABLE BELOW DECKS AUTOPILOT AND A VERY GOOD REFRIGERATION UNIT.
THE LIMITED RESEARCH I HAVE DONE SO FAR HAS COME UP WITH THIS:
THE STEERING QUADRANT AREA BELOWDECKS PRESENTS A PROBLEM FOR AN AUTOPILOT BECAUSE OF THE LIMITED SPACE.
WITH REGARD TO REFRIGERATION,IT IS WELL WORTH GOING FOR THE EXTRA COST OF AN ENGINE DRIVEN INSATALLATION...even for coastal cruisers. I WOULD GREATLY APPRECIATE ANY FEEDBACK....THANK YOU



jcp1347@gateway.net

[Bill]

HELLO FELLOW CD OWNERS,
ALTHOUGH OWNING MY CD36 FOR 14 YEARS, I THINK IT IS TIME FOR A RELIABLE BELOW DECKS AUTOPILOT AND A VERY GOOD REFRIGERATION UNIT.
THE LIMITED RESEARCH I HAVE DONE SO FAR HAS COME UP WITH THIS:
THE STEERING QUADRANT AREA BELOWDECKS PRESENTS A PROBLEM FOR AN AUTOPILOT BECAUSE OF THE LIMITED SPACE.
WITH REGARD TO REFRIGERATION,IT IS WELL WORTH GOING FOR THE EXTRA COST OF AN ENGINE DRIVEN INSATALLATION...even for coastal cruisers. I WOULD GREATLY APPRECIATE ANY FEEDBACK....THANK YOU

;Charlie I can't help you with the auto pilot question our CD28 has a tiller and we use a Tiller Master unit that works great but it a above decks model. We do have refrigeration, it's Seafrost engine driven and keeps the fridge box cold and makes all the ice we need for drinks, usually a 45 minute charge will hold over for 24 hours,when the temps in the 90's two chargings will be needed.Best of all the batteries get charged at the same time so no need to skimp on using the lights,etc
Bill & Jayne
CD 28 Infinity



tocoiriverrats@aol.com

[Larry DeMers]

Charlie,

One thing first..turn off your Caps Lock..it is interpretted as *SHOUTING* on the internet..and clearly, I/we can hear you very well.
Ok, refrigeration; I will disagree with you about the engine driven vs. electric driven compressor being better..more powerful (for large systems) certainly in some cases. But for the majority of installations, you will find an electric system installed. One of the considerations is the HP drain when you are using the compressor. In my CD30, I have only 13hp to work with. Probably only 10 of that is really there to be used to do work, so when you take off 3-5 HP for that compressor, it effects your capabilities greatly. The answer to this problem would be a separate override control on the compressor to allow the engines full power at the prop should it be needed.

But certainly, the majority of the boats represented on this listserver would be better served with an electric compressor due to available HP alone.

The electric system has several really nice advantages. Because it is run off of 12vdc all the time, it will never know if you are tied to the docks power or on your own batteries. Ergo, you are able to keep the reefer cold during the week while away from the boat. Try that with an engine-only driven system ;^).
Another advantage is that the systems tend to be lighter, less expensive, and smaller in size. Efficiency improvements on the Danfoss compressor (which most electric systems use now)have made it possible to run my refeer (to be installed as soon as Defender gets their act together and sends it to me!)for 24 hrs. and consume only 16ah of battery capacity. Comparing this to something we can all size up..an anchor light drawing 1.5 A, and run for 11 hrs. takes the same power!
Now granted, the size of my box is only 6 cu.ft., and I bought the new Isotherm ASU/SP Holding Plate system, which uses the boats own galley sink seacock as a heat exchanger for the refrigerant, eliminating fans and water pumps. But I will have a separate freezer section, with a spill-over gate to the reefer section, and this will work very well for us. We are coastal cruisers on Lake Superior, and spend anywheres from 2-3 days to 3 weeks out on the lake away from a supply point or civilization. At times this summer, we will be 75 miles from the nearest telephone or road. The electric refrigeration system we are installing in a few weeks should be the exact system that we need.

Lastly, my own research showed that more folks use an electric compressor than an engine driven one. But that fact may be misleading in that it depends on the intended use and size of the boat. Purely ocean cruising in a 40+fter., then engine driven is probably the way to go. Change the equation to a smaller boat, or more coastal cruising, then the electric system seems to be quite a bit more popular.

Cheers!

Larry DeMers
s/v DeLaMer
Cape Dory 30 Sailing Lake Superior

HELLO FELLOW CD OWNERS,
ALTHOUGH OWNING MY CD36 FOR 14 YEARS, I THINK IT IS TIME FOR A RELIABLE BELOW DECKS AUTOPILOT AND A VERY GOOD REFRIGERATION UNIT.
THE LIMITED RESEARCH I HAVE DONE SO FAR HAS COME UP WITH THIS:
THE STEERING QUADRANT AREA BELOWDECKS PRESENTS A PROBLEM FOR AN AUTOPILOT BECAUSE OF THE LIMITED SPACE.
WITH REGARD TO REFRIGERATION,IT IS WELL WORTH GOING FOR THE EXTRA COST OF AN ENGINE DRIVEN INSATALLATION...even for coastal cruisers. I WOULD GREATLY APPRECIATE ANY FEEDBACK....THANK YOU

demers@sgi.com

[Ken Coit]

I defer to DeMers on reefers. We use close contact with the hull to keep our water and drinks at cooler-than-air temps.

On autopilots, I don't know much either. However, Parfait has an Alpha Spectra underdeck unit that works well. The drive unit extends into the starboard cockpit locker and the mounting bolt for it peeks through the aft bulkhead of the pilot berth. Taking dimensions from the manual, not the boat, the lever arm on the rudder shaft is either 18 or 24 inches long, and the distance from the center line to the end of the drive unit is either 27 1/2 or 38 inches long. If you want to know more about this particular installation, I'll be happy to take measurements and photographs when we next get to the boat (sigh). As for Alpha Marine Systems, although they made autopilots of high quality and reliability (they are often found on commercial and Transpac boats) I am afraid they are defunct. If anyone knows better, I'd certainly like to have contact info.


Ken
CD36 #84
Parfait
Raleigh, NC

HELLO FELLOW CD OWNERS,
ALTHOUGH OWNING MY CD36 FOR 14 YEARS, I THINK IT IS TIME FOR A RELIABLE BELOW DECKS AUTOPILOT AND A VERY GOOD REFRIGERATION UNIT.
THE LIMITED RESEARCH I HAVE DONE SO FAR HAS COME UP WITH THIS:
THE STEERING QUADRANT AREA BELOWDECKS PRESENTS A PROBLEM FOR AN AUTOPILOT BECAUSE OF THE LIMITED SPACE.
WITH REGARD TO REFRIGERATION,IT IS WELL WORTH GOING FOR THE EXTRA COST OF AN ENGINE DRIVEN INSATALLATION...even for coastal cruisers. I WOULD GREATLY APPRECIATE ANY FEEDBACK....THANK YOU

parfait@nc.rr.com

[Matt Cawthorne]

Charlie,
I could not disagree with you more about the type of refrigeration unit. If you have an engine driven unit, you become a slave to it. You have to be there and run the engine when it needs it.

My first recommendation is to insulate the box properly. My 1982 CD-36 had very poor insulation in the icebox. I could barely keep the box cool with an electric unit. Two sides had two inches of foam, three sides had only 1 inch, and the top had no insulation beyond the plywood lid in some ares. Last year I did a re-build on my box and refrigeration unit. I went to a freezer with a spillover frige unit. I used 5 inches of foam as a minimum, with 7 inches in some areas and R-50 vacuum panels backed up with 1 inch of foam for the top and engine side. I used a Frigoboat electric unit. It was a lot of work. I did a series of tests with an ammeter and timer and found that the unit will use around 27 Ah of electricity per day with the Freezer at 26F and the frige at 40F and the outside temperature at 80F(those numbers are from memory so may not be exact). That represents about 10% of the battery capacity per day. If not much else is using electricity I could reasonably go for 4 days without using the engine. With supplimental generation capability such as a wind generator and/or solar panels the engine will be needed even less.

The cost of running the engine turns out to be fairly high. The fuel is minimal, but when you add the wear and tear and it's associated maintenance and the fact that the engine will need to be replaced sooner it really adds up. I think I remember that the cost of running a small boat diesel is around 2.65/hour. I think that they were under-estimating the cost. The other issue that is far larger for me is that when sitting in a quiet anchorage, tied up to a dock or sailing the last thing that I want to hear is an engine running. If you use an electric unit you can charge the batteries while motoring in and out of anchorages or when at a dock. Some engine driven frige units can be harmed by running them too fast. For that reason you have to be careful if you are using the frige when you might need a burst of power, such as setting an anchor or maneuvering around docks.

Good luck. I remember that while crossing the Atlantic about 10 years ago with no refrigeration, I would have give $50 for a glass of ice water.

Matt




mcawthor@bellatlantic.net

[Tom]

Charlie,
I could not disagree with you more about the type of refrigeration unit. If you have an engine driven unit, you become a slave to it. You have to be there and run the engine when it needs it.

My first recommendation is to insulate the box properly. My 1982 CD-36 had very poor insulation in the icebox. I could barely keep the box cool with an electric unit. Two sides had two inches of foam, three sides had only 1 inch, and the top had no insulation beyond the plywood lid in some ares. Last year I did a re-build on my box and refrigeration unit. I went to a freezer with a spillover frige unit. I used 5 inches of foam as a minimum, with 7 inches in some areas and R-50 vacuum panels backed up with 1 inch of foam for the top and engine side. I used a Frigoboat electric unit. It was a lot of work. I did a series of tests with an ammeter and timer and found that the unit will use around 27 Ah of electricity per day with the Freezer at 26F and the frige at 40F and the outside temperature at 80F(those numbers are from memory so may not be exact). That represents about 10% of the battery capacity per day. If not much else is using electricity I could reasonably go for 4 days without using the engine. With supplimental generation capability such as a wind generator and/or solar panels the engine will be needed even less.

The cost of running the engine turns out to be fairly high. The fuel is minimal, but when you add the wear and tear and it's associated maintenance and the fact that the engine will need to be replaced sooner it really adds up. I think I remember that the cost of running a small boat diesel is around 2.65/hour. I think that they were under-estimating the cost. The other issue that is far larger for me is that when sitting in a quiet anchorage, tied up to a dock or sailing the last thing that I want to hear is an engine running. If you use an electric unit you can charge the batteries while motoring in and out of anchorages or when at a dock. Some engine driven frige units can be harmed by running them too fast. For that reason you have to be careful if you are using the frige when you might need a burst of power, such as setting an anchor or maneuvering around docks.

Good luck. I remember that while crossing the Atlantic about 10 years ago with no refrigeration, I would have give $50 for a glass of ice water.

Matt

I have an engine driven refrigeration unit and have never experienced the things you mention here. With an engine driven unit you have a cold plate that stores the cold so that you don't have to run the engine everytime the box needs it. After the initial pull I run the compressor about half an hour per day to keep it frozen solid. It has to be run at the idle so you never run it when you are running at cruising speed or pulling into a harbor ar anyplace where you will need engine power. If you don't fun it "when it needs it" the box will last three days before the plate loses it's cooling completely.

Thus my pattern is first thing in the morning after you've had the running lights on all night and have maybe run the autopilot, I start the engine and run it at slightly above idle for about half an hour. This puts the charge back in the batteries and while you're at it refreezes the cold plate. Now you shut it off and don't run it again at least until the next morning and if you want to wait for the next three days. It's never been a bother and I certainly never feel like a slave to the unit. You've only got to run it for a half an hour a day so there would never be a reason to run it just as you're entering a harbor or when you're pushing into a head sea and need engine power. If you're entering a harbor you'd just wait until you're inside and anchored down and then click it on for a half hour while you're getting things put away.

People with electrical refrigeration found that in the warm climates like Mexico the motor was running almost constantly even at night and the motor kicking on would keep you up at night worrying about electric drain. Not only that, if you're not water cooled you're pumping hot air into the boat as it blows across the radiator what you don't need when you're already toasty.

It sounds like you've really insulated well and maybe that would help with the electric drain. Whichever system you use good insulation is important. And I would say being water cooled is equally important. A lot of people have problems with electric units from sticking them into little cabinets without adequate air circulation around them if air cooled. I've had electric and engine driven types and I prefer the engine driven type. If I build one again though, I'm going to make it a hybrid. Put two coils in the cold plate one that runs on electric so that you can use it without running the engine when you're tied to the dock and the other that is engine driven that you can use when you're sailing.

People often tell me that they couldn't have an engine driven system because they are under powered and they wouldn't want the drag on their engine. I have to wonder if they have ever actually used an engine driven system, because you'd never run it in conditions like that. One of the great advantages of the engine driven system is that you only run it for a total of half an hour a day and that's all at one time and you choose the half hour which isn't when you're maneuvering in a harbor or pounding into a head sea.

There's a lot of different ways to do things and everybody finds the system that works for them. It's not like one is right and the other is wrong. A poorly designed system will give you trouble whether it is electric or engine driven of course.



TomCambria@mindspring.com

[matt Cawthorne]

Tom,
What model do you have and have you re-insulated it? The 36 has a big box and poor insulation. You are the first person that I personally have talked to with engine driven refrigeration that could go more than one day before running the engine and still keep the box cold.
My comment about "whenever it needs it" was meant to imply whenever the holding plate needs re-freezing. I think that you are making my point about overspeeding the compressor. To avoid that you need to run the engine while at anchor. I did not make that real clear. I have been on boats with poorly insulated boxes that needed 45 minutes of engine time twice daily. It was painful to be in paradise listening to the engine run all that time. I had the misfortune to be tied to a sea wall in Bermuda (stern to stern) with a boat that had to run it's engine daily to refrigerate. We moved elsewhere. The CD-36 (at least the ones of my vintage) had poor insulation and in the summer on the Chesapeake would use 15 lb of ice per day. With the 36, running the engine adds to the heat load of the box because of the proximity and layout. The cutouts for the engine mounts actually allowed the heat from the engine compartment to surround the box on 3 sides.

In my opinion insulation is the key. It is a lot of work to do a really good job on the 36. In my case I ended up with about 60% of my original volume. By my calculation that cut the amount of electricity down by a factor of 3 (at least).

I also agree that water cooling is important. My old unit was air cooled and sat in a hot cockpit locker. I figure that another factor of 1.6 was gained by going to a keel cooler. It is a well known fact that the coefficient of performance is tied to the temperature of the place where the heat is being dumped to. If you have an air cooled unit then you would do well to provide lots of ventilation to the area where the unit sits.

My unit has approximately 30% duty cycle in 80 degree temperatures. It is hard to hear it when you are listening except that the thermostat makes a small click when it turns on. Even with a 100 % duty cycle it could not take more than 60% out of one of my group 31 batteries in a 24 hour period. On vacation last summer we had ice cream on the 4th day of the trip for Ali's birthday. I had to run the freezer somewhat colder than normal for that and still never had to run the engine specifically to charge the batteries. They got all that they needed while going in and out of anchorages.

I must agree that everyone has their own requirements and perhaps others do not hate the sound of the engine as much as I do. The electric unit with a keel cooler and good insulation is a quiet, economical solution that I prefer.

matt



mcawthor@bellatlantic.net

[Tom]

Tom,
What model do you have and have you re-insulated it? The 36 has a big box and poor insulation. You are the first person that I personally have talked to with engine driven refrigeration that could go more than one day before running the engine and still keep the box cold.
My comment about "whenever it needs it" was meant to imply whenever the holding plate needs re-freezing. I think that you are making my point about overspeeding the compressor. To avoid that you need to run the engine while at anchor. I did not make that real clear. I have been on boats with poorly insulated boxes that needed 45 minutes of engine time twice daily. It was painful to be in paradise listening to the engine run all that time. I had the misfortune to be tied to a sea wall in Bermuda (stern to stern) with a boat that had to run it's engine daily to refrigerate. We moved elsewhere. The CD-36 (at least the ones of my vintage) had poor insulation and in the summer on the Chesapeake would use 15 lb of ice per day. With the 36, running the engine adds to the heat load of the box because of the proximity and layout. The cutouts for the engine mounts actually allowed the heat from the engine compartment to surround the box on 3 sides.

In my opinion insulation is the key. It is a lot of work to do a really good job on the 36. In my case I ended up with about 60% of my original volume. By my calculation that cut the amount of electricity down by a factor of 3 (at least).

I also agree that water cooling is important. My old unit was air cooled and sat in a hot cockpit locker. I figure that another factor of 1.6 was gained by going to a keel cooler. It is a well known fact that the coefficient of performance is tied to the temperature of the place where the heat is being dumped to. If you have an air cooled unit then you would do well to provide lots of ventilation to the area where the unit sits.

My unit has approximately 30% duty cycle in 80 degree temperatures. It is hard to hear it when you are listening except that the thermostat makes a small click when it turns on. Even with a 100 % duty cycle it could not take more than 60% out of one of my group 31 batteries in a 24 hour period. On vacation last summer we had ice cream on the 4th day of the trip for Ali's birthday. I had to run the freezer somewhat colder than normal for that and still never had to run the engine specifically to charge the batteries. They got all that they needed while going in and out of anchorages.

I must agree that everyone has their own requirements and perhaps others do not hate the sound of the engine as much as I do. The electric unit with a keel cooler and good insulation is a quiet, economical solution that I prefer.

matt

Matt, I think we are fundamentally in agreement. Once you define all the little if's and but's we come out to the same conclusion. My unit is a home built system based on a compressor from a Toyota I believe it was -- anyway the kind that doesn't have valves but a rotating disc and is guaranteed for life. I have a CD31 and like all the CDs came with essentially no insulation on the icebox. I re-insulated it and built the largest cold plate that could possibly be put inside. The original cold plate had 3/8 inch copper tubing, but when I had trouble with it in Mexico I had a Canadian regrigeration expert who was sailing to Panama and passing through rebuild it. He changed the tubing to 1/2 inch and made some other modifications. Getting the right design is essential and maxing the insulation is really important.

I sure wouldn't be happy with a system I would have to run 45 minutes twice a day. One time I forgot to shut the system off and let it run at cruising speed for three hours. The beer froze and exploded the cans. I had an unhappy crew and a sticky, smelly mess to clean up.

I crewed on a Cheoy Lee wooden yawl once in Mexico in 100 degree weather. Their electric box cycled on even 20 minutes and ran for 20 or 30 minutes per cycle, day -- and night. When it cycled on it put a vibration all over the boat and you could hear it running when you put your head on the pillow. I didn't like that either.

So let's take as givens that you have a well insulated box that you've insulated yourself because as they come they certainly are indequate. Then you've added a well designed system that is efficient, water cooled and doesn't make a lot of noise. At this point I think we are in agreement, i.e., there are advantages and disadvantages to both systems and it's owner's choice.

The main disadvantage to engine driven systems in my view is the necessity of running them at less than 1000 RPM for half an hour (in my case) every day. Not so bad for you but rather impolite for the boat behind you eating your exhaust. The main downside to the electric ones in my view is the electric drain and all those wire connections that potentially corode. You can work around these things by designing the system correctly maybe adding solar panels or wind geneators or battery banks etc. As with all things on boats it's always a trade off and you have to do everything right in the initial design. So I think we're in agreement. A poorly designed engine driven system compared to a well designed electric system would certainly lose, but by the same token a poorly designed and insulated, air-cooled electric system compared to a well designed engine driven system would lose also. So I think what we're both arguing for is a well designed system that is well made. Couldn't agree more.

BTW the Canadian guy (I wish I could remember his name to give him credit - it's in my log on the boat) said that in his engine driven system he filled the cold plate with plain water rather than eutectic solution. He said he only ran the compressor once a week to freeze the water. Since water freezes more quickly than alcohol it didn't take long to freeze. Of course it never got colder than 32 degrees so he couldn't keep ice cream or frozen foods -- he used it like an ice box. I should add that I never keep my box cold enough to keep ice cream or frozen foods either. I would have to run it more than half an hour a day to get it that cold.

Regards, Tom



TomCambria@mindspring.com