Keeping it warm, cool, dry, quiet - The benefits of insulation

No one wants to be cold and wet on a boat. I mean the whole idea is to go somewhere warm and wonderful, right? And if it's not warm outside, then the boat should be a cozy and welcoming retreat.

But boats get wet inside.  Clearly water can come in from bad weather and waves. But damp air also condenses on the cooler hull and deck.  And when things don't dry out it leads to mold and "boat smell" not to mention related health implications. 

This post is about how we are insulating the boat to mitigate these problems.  Another benefit is.....it's quieter.  :-)

Most production boats aren't insulated or the insulation is minimal.  The cabins are often built with a core construction - that's balsa wood with fiberglass on both sides. The insulating value is modest and when the fiberglass cracks (from some unanticipated impact) then water can get it.  It probably won't dry out and then the balsa wood rots and potentially molds.  Even without cracks and penetrating water, non-insulated walls are vulnerable to condensation and the resulting dampness.

AtLast won't have any core construction.  AtLast is solid fiberglass construction with wood framing.  The wood is sealed with penetrating epoxy or painted with anti-mold bilge coat.  And in many cases we are using black locust wood, a hard wood that is rot resistant. 

The fiberglass and wood structure doesn't insulate so we are insulating the hull and cabin. This should produce a strong boat that is warm, drier, and resistant to rot and mold.  Once we are in the tropics, the insulation will help keep the cabin cooler.

So what are we using for insulation? 

It's Armaflex, a dense rubber elastomer based material with special qualities:

• it's closed cell foam, so it doesn't absorb water
• it's anti-mold
• it's non-toxic if burned
• it dampens noise
• it doesn't break down over time
• it's easy to cut and flexible so if fits easily into odd spaces.
• it's light weight
• it's not cheap at $5 per square foot.

We are insulating all around the boat above water line.   Anything below waterline, however, will not be insulated.  The reason is that it is important to be able to inspect for damage that could affect the integrity of the hull.  All of the below-water surfaces are painted with bilge coat and should be relatively easy to clean.

Before and after:  Adding insulation to the forepeak. 
The vertical rails are hull stiffeners.

The insulation can be cut by scissors or I use a band saw. 
It conforms into spaces under the deck as well as on the sides of the hull.

Here, insulation is being installed above the starboard settee onto the hull side. 

After installing the insulation, I attach varnished slats over it.  This protects the insulation and it will look great! There will be little gaps between the slats for air circulation.  You can see here that I painted the stiffeners black.  I did this so they will be less visible through the air gaps.

Here are some varnished slats ready for installation in another cabinet. 

The varnished slats are ready to be installed in the picture above.  They will be installed like "paneling" on the back wall, which is, of course, the hull.  In boat language, the hull sides are called the "ceiling".  How's that for confusing?

The stiffeners give me something to attach the slats to.  I drill holes into the stiffeners and screw the slats into place.

We glued and stapled roughly 200 ft of little 1/2x1/2 ribs onto the deck beams.  The ribs have two purposes.  One is to hold up the insulation so it doesn't fall out and secondly, they provide a surface to which we can attach wooden paneling.  The paneling will be white and it will brighten up the cabin.

We are about 70% done installing insulation. There are storage areas in the bow and stern of the boat that are still bare.  Getting to these areas will require crawling into tight spaces.  That will be a little more challenging!