Condensation and Insulation

[AlexR]

Hello Fellow boat owners 😂

I am sure this topic is on many a yacht owners topic of discussions..

**INSULATION AND CONDENSATION**

We have a Ferro yacht and busy doing a refit of sorts. I would love to know what everyone does or has used for insulation on the hull, be it above and below the waterline. In cupboards and in the open. We have “bare hull” in all three cabins, previously had carpet glued on with no rubber or foam behind the carpet.
Do i replace with carpet or what else is everyone using.
The boat is currently in Melbourne(cold climate) we will be travelling north to warmer climates in summer.
Thanks

[atoll]

my ferro used to rain inside if any heating was on in cold weather,untill i discovered that leaving the front hatch cracked open to allow a bit of airflow stopped the problem!

no insulation at all as the boat was built and remained most of its life in the tropics,untill i moved it to turkey.

our other aluminium yacht has 2 inch styrofoam throughout to the waterline which works great for heat insulation in hot climates,but not so good for cold climates.
where condensation can be a problem if not ventilated.

our catamaran is fully insulated above and below the waterline with seals on all the doors and windows with an adjustable vent for airflow inside in very cold weather,opening the hatchway door you can feel the vacume when you open the door if the vent is closed,so a high degree of airtight integrity to avoid heat loss.

the insulation is 1" cellotex insulation board and 2" under the floors,plus 1/2"balsa core on the decks.

heater is a sigmar diesel burner 2-4kw with closed system air intake ie it takes combustion air from outside and exhausts out the chimney.

in 0 degree weather we have 20-22C inside with the air circulation vent open about 1 cm and the heater running on its lowest setting~4 liters diesel in 24 hrs
currently i am fitting double glazing on all the fixed windows to eliminate condensation between the cold hot window surfaces.
openable hatches will have removable neopreme insulated sunbrella hatch covers.

if you could i would reccomend PU spray foam insulation of the whole of the interiour and under floor insulation in cellotex with ventilation points at the front and back of the accomodation on the boat to ensure airflow through the boat

[Andreas W]

On my steel boat I used a product called Solarshield. It's an acrylic polymer blended with ceramic microspheres. It is primarily being used on metal roofs. The layer is only 500 micron thick (0,5 mm).

I did not like to use foam for a number of reasons, the main reason being that you can't see what happens behind the foam on a steel hull.