Air/Heat Duct Work ???

[Scott]

As most of you know we are installing a heating and cooling system in our Columbia 34. I have having a hard time on how to run the duct work I am considering using the wall cavity (like used in houses) as my duct run since it will be difficult to run any ducts or flex pipe to this location. I my picture below you can see a hatch pattern the represents a board that I would like to install to make the air run in the wall cavity, and how the air will be let out of the space through some custom window boxes in the areas the previous owner made to install some port windows. The unit is gettting installed in a locker fwd (to the right in these pictures) of the couch, there is no problem running the duct work fwd into the v-berth.

Is this a bad plan, anyone see a better way to to this? I want to do it the best way possible.

 

[Ross]

Why mess around with duct work?

This is just one little room that you are dealing with. A couple of small fans will distribute the chilled air/heat through-out the entire space.

 

[Scott]

Not Needed?

I would think some sort of duct would would be required? If not your going to end up with one are being really cold and other areas like the v-berth not getting much air, plus now you have to run fans to move the air around.Scott

 

[Tom Spohn]

Cold Feet

On my boat the heater puts out plenty of heat but it is at shoulder level. If I understand the pictures in the post the ducts would exit just below the windows (ports) at about shoulder level. This makes my boat toasty warm but with cold feet at floor level. Placing extra fans about helps somewhat but the sole is still not very even in my 35 ft boat. I am planning to run ducts under the settees to blow warm air just above floor level.

 

[Scott]

What do you thin?

So are you saying that I can use the wall cavity as duct work?

 

[Ross]

The air isn't going to walk through those ducts

by it's self you will still need a blower. Since warm air rises a fan mounted at the high point in the space will blow it towards the floor, mix it with the cold air and if you don't like the results you can move/angle the fan to blow in another direction. In your house on land you have a warm air supply duct for each room(if you have forced air heat) and a cold air return either in each room or centrally located for the house. On the boat you could easily direct the air from the floor to flow past the heater and circulate through the cabin. The only place that I could mount my Force 10 heater in Bietzpadlin was about four feet above the floor A 1 watt 30 Cuft/min fan blowing up towards the fan keeps the cold off the floor and the cabin comfortable.

 

[Len]

Be careful

Most of these little units that I have seen have very small, weak fans in them and can not handle the friction loss or static pressure of a lot of ductwork. If you reduce the air flow across the heating/ cooling coils too much you will have all kinds of problems with the cooling coil icing up or the electric heaters tripping on thermal overload. Keep your ductwork to a very minimal amount. Keep your return air intake low and your discharge air high.

 

[Scott]

Maybe I am lost

We are installing a Mermaid Air 16.5k btu unit in the bottom of a locker the unit has a 6" dischage and fan on it. I need to run the 6" discharage to the salon area and 4" to the v-berth. There will be a cold air return cut in below the locker door for the unit to suck air in.Scott

 

[Steve Dion]

high heat loss thru the hull

Scott:You are probably going to loose a lot of heat thru the hull. This heat is going to disperse through out the entire cavity. Even if you place fans around the boat I think that much of the heat is going to be gone by the time you blow it out of the cavity area. I would suggest that you consult with a professional that does this and see if they can give you any pointers. I know that some of the systems have smaller ducting to make it easier to run around the boat.