Do-It-Yourself insulating your boat with pressurized bottles of foam BEWARE!

From what I see on the pictures, you have insulated the hull by spraying polyurethane foam from InstaFoam or similar (2 pressurized small tanks, with a light spray gun). Or maybe from some professional having similar or slightly more sophisticated equipment. I assume this from the granular aspect of the final surface. Only top specialists, with years of rigorous activity and manual practice and top equipment can provide constant, regular, smooth finish.

Please note that you need to respect a few conditions for success:

1- underlaying surfaces must be thoroughly protected in terms of anti-corrosion: one or 2 layers of top-quality zinc based paint (or equivalent anti-corrosion primer system), and 3 to 8 coats of epoxy-based or polyurethanne-based (better: tar-epoxy based or tar-PU based) 2-component, preferably solventless paints.

2 - The steel must be protected from general corrosion, but also from the free chemicals that are always present in incompletely mixed polyurethane foam, specially when the foam has been produced (chemically in fact) by a rather less reliable process like these small outfits. Compare the instafoam pistol with a state-of-the-art pistol, whose smaller models cost 2000 pounds, and are linked to a 20 to 40-thousand pound processing equipment: instafoam will at best mix 95% of the one component with 95% of the other, and the rest is free chemicals imbedded in the final foam product.

3 - The foam from such process is limited to specific densities, fire resistance, chemical and physical resistances that are far from ideal specs for a boat, more even for a boat in extreme climates. Ie. that foam is probably around 30- 35 Kg per cubic meter (2 lbs per cubic feet), we recommend nothing less than the double density, avoiding issues as irregular cell structure, bigger cells size, micro cracks in the structure, retraction, lower impact resistance, lower adhesion, etc. Whith lower densities and physical specs, when extreme temperatures and extreme temperature differences hit the foam, the problems start to appear, or worse.. don't show but still exist.

4 - Fire resistance. We recommend nothing lower than the top specs, wich is so good that we use it officially as fire barriers in public spaces. Some lower specs are acceptable and will resist some time to some extend to participate in external source of fire, but most are qualified as some of the "auto-extinguishing" arguments that are a shame in practical terms: it will only autoextinguish if the source of fire it totally withdrawn, and the burning surface is smaller than my hand, without wind, etc... Fire is a main cause of boat major accidents ! Most materials in boat construction are dramatically helping a small incident in becoming a totally destructive fire in less that a minute.

5 - Vapour migration. You *must* cover your insulation with a near-perfect vapour barrier on the "warm side". Water vapour is everywhere in the air, more of it in warmer air. Is is physically a gas, and it permanently tries to migrate from the warm, vapour containing air, to the other side of the wall/ insulation where the colder air contains less water vapour. It migrates through almost all materials: water being one of the smallest molecules, it passes through the molecular structure of most materials, excepted: metal and glass thicker than 1/100th of millimeter, tar, some very specific and expensive plastics and paints, and a few others. Almost all other materials, however compact, let the water vapour pass through them. That is what people wrongly name "breathing materials" when they refer to house building.
In the case of a boat in colder weather, and much more in arctic environment, the water vapour contained in the air inside the boat, augmented by the water vapour you add by breathing and expelling body water, plus the vapour from the heads, kitchen, etc, .. all that vapour penetrates slowly in all materials in the boat. Now think about the hull: the vapour passes behind or through the finishings, through the foam, until it reaches a point near the hull where the temperature is much lower than in the place it comes from, because the temperature outside the boat is lower than inside. At that point, the vapour condensates, becomes liquid water, and still tries to migrate to the exterior... somewhere further deep in the foam, nearer to the hull, maybe the temperature is under zero degrees celsius ( = centrigrades = -32 degrees fahrenheit) because it is "freezing cold" outside. And there, the liquid water becomes solid, it freezes. Water freezes by expanding its volume, breaking everything constraining it: the foam cells will slowly be destroyed, fill up with water or ice, dramatically augmenting the the vapour permeability and lowering the insulating ability of the foam, therefore increasing the speed of migration of vapour and letting the dew point and the freezing point moving progressively through the insulation layer towoards the inside of the boat.
Resulting in dew, mildew, all sorts of parasite forms of life, bad insulation, and so on.
If the hull is of metal, the water on its inside surface, combined with the free chemicals in the foam, can lead to total disaster if the metal is not very strongly protected by the above-mentionned paint system.
You can also see that this phenomenon is dramatically increased on "thermic bridges" where more conductive materials are not covered by the insulation, like the hull's reinforcement ribs protuding form the insulation layer.

6 - The only way to avoid this is to encapsulate the warm side of your insulation with a strong and near to perfect "vapour barrier". That could be 1- 2 millimeters thick sheet of bitumen material, but very impractical to apply. Alternatively, some bitumen / tar based thick coatings could be appropriate, if you lay a few coats of it, making shure the uncovered spots of each coat are covered by the other coats, same for the "pinholes" left open by any paint / coating drying by evaporating its solvent medium.
That product needs to be adhesive to foam, not to sensitive to fire, odourless (most tar products are for outside usage and smell strongly), and sufficiently flexible to follow the surface slight movements of the foam. More flexible for lower density foam.. And you need to apply it on a continuous layer over all the inside of the insulated hull, joining it to any and all protuding items.

Some special paints have high level of water vapour impermeability, like some chlorinated-rubber base paints used amongst others for swimming pools. But they are very expensive, and high solvent content: the solvent goes away, so you pay a lot for little stuff that remains, and the solvent evaporation is the cause of the microscopic pinholes in each layer that need other layers to be covered.
Worse, each dry layer is quite thin, following the irregular surface of the sprayed foam, resulting in using 1.5 to 2 times more paint than if the surface was plane. That issue is well covered by bitumen products, being very pasty and thick the first layer will probably amount to 2 mm, acting as a filler of the irregular foam surface.
Apart true bitumen-based products used for their low cost, most other water vapour products *must* specify that ability in their specs, so you can compare them. Bitume-bases also need to be confirmed in their specs, and "calculated", but generally speaking the result / cost ratio will be 5 to 20 times better.