Headliner Insulation to Keep Heat OUT (hot climates)

[Danibug]

Does insulating a 2" thick plywood cored cabin top really cut down on the heat from the sun or is it just fooey?

I have read through many of the threads on CF today on this topic and most seem to deal with how to keep the heat in as if from a heater so I wanted to start a new thread on this topic.

I just removed the gross headliner in the vberth and head in our Westsail 32 and am wondering what I should put back up. I have read many good things about "Eco foils Double Bubble" insulation wrap but if I understand the installation correctly you need to have a 1/2" air space between the cabin top and the bubble wrap for it to work.

But in leaving an air space you are opening yourself up to a mold issue.

What should be used on the overhead to keep your boat cool in the tropics (NO air conditioning) and how should it be installed?

I was thinking that maybe the thick plywood core deck would provide enough insulation where it wouldn't matter.

Thanks so much!!

[jgbrown]

Armaflex, Volara or other similar closed cell foam are much better than the darn foil in my opinion. I'd actually really like to see somebody try the new Volara foam that is laminated at the factory to a top layer of HDPE plastic or similar, it would save a lot of labor!
I plan to try that new version out in lockers on my next boat.

[Ocean Girl]

I put reflectex in my Geminii cat before redoing the headliner. I did not do a gap,didn't know about that, thought the bubbles were the gap.
Anyways, was a big improvement for summer heat. Not sure about Keeping interior heat in.
Erika

[Sailmonkey]

The best thing we found for tropical heat was an awning.....well worth the material cost!!

[FSMike]

Originally Posted by Sailmonkey

The best thing we found for tropical heat was an awning.....well worth the material cost!!

What he said.

[thinwater]

Originally Posted by FSMike

What he said.

What he said.

Plus window covers. White is MUCH cooler than a dark tarp, even if you need to paint the top surface.

[Ocean Girl]

But...since Danibug has the headliner off it would be good to add insulation of some type.
Here is another thread on it to add to the confusion
http://www.cruisersforum.com/forums/...ior-66124.html

[bobconnie]

Used the bubble insulation on a steel boat, put it up with 5200on walls and overhead, 2 layers on both! worked well. No space and never any mold ! Kept heat in and cold or heat out ! Just sayin I got it at ace hardware! LOL And by the way, we coverd it with dyed jute material! sorta looked nice if I say so myself!!

[Adelie]

Originally Posted by Danibug

Does insulating a 2" thick plywood cored cabin top really cut down on the heat from the sun or is it just fooey?

I have read through many of the threads on CF today on this topic and most seem to deal with how to keep the heat in as if from a heater so I wanted to start a new thread on this topic.

I just removed the gross headliner in the vberth and head in our Westsail 32 and am wondering what I should put back up. I have read many good things about "Eco foils Double Bubble" insulation wrap but if I understand the installation correctly you need to have a 1/2" air space between the cabin top and the bubble wrap for it to work.

But in leaving an air space you are opening yourself up to a mold issue.

What should be used on the overhead to keep your boat cool in the tropics (NO air conditioning) and how should it be installed?

I was thinking that maybe the thick plywood core deck would provide enough insulation where it wouldn't matter.

Thanks so much!!

Do you know that it was 2" thick by measuring through a hole in the deck or is this a guess. I would expect your deck to be 1 to 1-1/2" thick with coring. Could be wrong, it is a W32.
Plywood is about 1.25/inch
Solid fiberglass is about 2.5/inch although I am not certain and am investigating further.

I would expect your deck to have an R value of 1.5 to 2.5.

Foam insulation gives 3.5-6.5 per inch depending on the material.
I have found a few different values for bubble wrap, varying from 2/inch to 1.3 per 3/8".

Using 2 layers of bubble wrap I would count on about doubling your insulation value.

Keeping the heat off in the first place using an awning would probably work just as well expect underway.

Personally I would do both.

I've always wondered what the temp of seawater is 10-20' down. Drop a hose overboard with the end weighted, pump the cold water up and through an old car radiator and then back overboard. Run a fan over the radiator and see what happens.

[HopCar]

I wanted to insulate my garage so I could work in it in the summer. I bought a cheap infrared thermometer, you know those things with a laser in them. I could measure the temperature of the ceiling with and without a piece of insulation so I knew if it was worth doing. Besides which, those things are fun.

[I.Grind]

I had to replace the insulation on the ducts in my house. I hired this guy to do it, he recommended his "special technique" which was basically to first put strips of the bubble wrap around the ducts, then wrap the bubble wrap around it (its what's in your link). It really works! Not even warm on the outside when the furnace is blasting. Maybe if you toss a couple desiccant packs in the airspace to keep it dry? As far as insulating value, I am impressed. You'd probably be fine just glueing it up with no airspace if you are really worried about the mold.

[Danibug]

Originally Posted by Adelie

Do you know that it was 2" thick by measuring through a hole in the deck or is this a guess. I would expect your deck to be 1 to 1-1/2" thick with coring. Could be wrong, it is a W32.
Plywood is about 1.25/inch

...
I've always wondered what the temp of seawater is 10-20' down. Drop a hose overboard with the end weighted, pump the cold water up and through an old car radiator and then back overboard. Run a fan over the radiator and see what happens.

From the internet oracle "The deck and cabin trunk is fiberglass cored with two layers of half inch plywood"

So you are correct it's probably not 2 inches. In the anchor locker there is a board underneath the fiberglass cored deck that adds another inch or so. The deck (overhead) in the vberth doesn't have that and is probably around 1 1/2" thick.

Since I have the headliner down I'm thinking I should do something and it's really really great to hear how many people have good luck with 2 layers of the bubble stuff.

I wonder if it's best to use the double foil on the layer closest to the cabin top and then use the "directional layer" with the white facing down as the second layer.

This part doesn't have to be fancy and I'm thinking of just leaving the white side be the finish. It's really cheap too.

I will look into the HDPE faced Volara foam as well although It's probably not as cheap or easy to work with.

An awning is of course the best thing but we had discussed only shading the salon and back of the boat (aft of the mast) while at anchor to lessen complications and gear storage. We plan to "keep on the move" during our hopeful trip around, not staying in one place longer than a few months at the most so storage is at a premium!

That last idea of yours is super awesome! I'm assuming after you hand pump the water into the car radiator it will create suction and pull the water continously through and back overboard? I suppose another option is to jump down yourself with your end weighted 10'-20' and cool off .

[Danibug]

Originally Posted by HopCar

I wanted to insulate my garage so I could work in it in the summer. I bought a cheap infrared thermometer, you know those things with a laser in them. I could measure the temperature of the ceiling with and without a piece of insulation so I knew if it was worth doing. Besides which, those things are fun.

What a great idea! I may actually do this while the headliner is down and summer is in effect. One benefit we have to living in the awful humid and hot weather of New Orleans is we know exactly how our boat will feel in the worst of conditions.

We (I) are somewhat desensitized to heat. I hear complaints about hot weather in the tropics but I wonder how much of that comes from people who spent their lives more north. I checked the temps in the carib on average and it seems they stay between 80-90 year round, with a breeze. That's not that bad...

[Danibug]

Originally Posted by bobconnie

Used the bubble insulation on a steel boat, put it up with 5200on walls and overhead, 2 layers on both! worked well. No space and never any mold ! Kept heat in and cold or heat out ! Just sayin I got it at ace hardware! LOL And by the way, we coverd it with dyed jute material! sorta looked nice if I say so myself!!

This is great. Was the steel boat in Louisiana? Any pics of your jute creation? I'm always looking to steal a good idea.

[Adelie]

Originally Posted by Danibug

That last idea of yours is super awesome! I'm assuming after you hand pump the water into the car radiator it will create suction and pull the water continously through and back overboard? I suppose another option is to jump down yourself with your end weighted 10'-20' and cool off .

So sorry that would be getting something for nothing, doesn't happen in physics (Except at the the quantum Level).

If the exit hose for the radiator is below the waterline, then there will be no net head to pump against, but there will be drag in the system so you will have to expend energy. I would use a cheap 12v pump drawing from a 3/4" garden hose and a 12v fan blowing across the radiator. The bigger the hose you can make work the smaller the drag loads and the smaller the pump draw on the battery.