insulation

[Hankthelank]

Hi folks,
I am not sure where I am heading on my sailboat, maybe the tropics but eventually up to British Columbia I hope. Any recommendations for proper sailboat insulation?
Cheers,
Hank

[MidLandOne]

Closed cell, sheets of soft, flexible closed cell insulation such as Armaflex or Korex glued to the hull are high quality choices with which you cannot go wrong. These are self extinguishing, resistant to most chemicals and petroleum products and won't rot. They are widely used on high quality yachts - both sail and power. But it is not cheap, especially if you have it installed by others and will be even more so if you cannot remove the existing interior hull linings easily.

We used it ourselves and can vouch for its effectiveness.

[Seychelles]

Ditto MidLandOne on armaflex. We spent a winter taking the interior of our boat apart and applying a layer of 3/4" armaflex to the inside of hill and topsides down to the waterline. It is applied with proprietary contact cement which works really good, even at cold temperatures. We injected spray foam into the places that were not accessible for armatex application. This greatly reduced condensation but did not eliminate it. We liveaboard in Juneau, Alaska and winter temps sometimes plunge to munis 5 F, though we find the cold fall rains the worst for condensation. In addition to insulation, we installed several 60mm 12 volt computer fans to circulate air into dead air spaces between the interior finish and the hull. This latter measure eliminated the condensation. We also use two dehumdifiers and can keep the boat at 45 to 50% relative humidity. Some days we pull three gallons of water out of the air. You may not have as much of an issue in BC, especially if in the southern portion. We find condensation issues start in earnest below 40F. It will ruin your boat and belongings if not attended to. Good luck.

[GordMay]

Me three on the efficacy of Armaflex.

Originally Posted by Seychelles

Ditto MidLandOne on armaflex...

Although Armaflex does not contribute to flame/smoke spread, their #520 adhesive contains flammable liquids (Hexane and Acetone which evapourate). Be careful when gluing it.

Originally Posted by MidLandOne

Closed cell, sheets of soft, flexible closed cell insulation such as Armaflex or Korex glued to the hull are high quality choices with which you cannot go wrong. These are self extinguishing...

[Hankthelank]

thanks guys for all your info!!

[Meridianpssg]

We are currently cruising the coast of BC Canada and are wintering over in Prince Rupert. Before we set sail from NZ in 1999 we completely insulated our hull and undersides of decks with Korex insulation (I think around 10-12mm thick) and then a front runner carpet over this. We went to a lot of trouble ensureing the Korex was well adhered to the glass surface etc. This product has in our experence been a total failure and here in Alaska and Canada our cupbds were dripping wet in this real cold enviroment. We have now removied this product from our sail boat and were astonished at how wet the Korex was when we pull it from the hull (it was still well glued) We have replaced all the insulation with R5 Polystyrene one inch thick foam leaving a good half inch gap around all edges and joins which we have filled with cans of insulation foam to ensure ALL the exterior surface is insulated.
As this is not an easy job to do in the first instance on a completed sailboat our only regret is that we did not do this the first time around.
We have been cruising and living on our boat for the last ten years the last four years in cold climates Japan, Alaska and now Canada. We have never been happy with the Korex insulation, having problems with dampness, mildew and just plain wet cupbds. We have always had a dehumidifier on board and plenty of fans for air circulation as well as a ducted Eberspacher diesel heater. But with Korex insulation nothing but dissapointment.
We are absolutley delighted with the results of the inch thick Polystyrene, Wet cupbds, mildew and dampness completly eliminated it is just YUMMY!
We are now confident (after a lot of work) that mildew and dampness for us is going to be a fading bad dream which we are very happy about.
I can't stress enough the importance in these cold climates of having a good dehumidifer aboard, with all the gas cooking and general living etc condensation is a real problem and no matter how good your insulation is without a dehumidifer you will have problems in extreme cold wet climates where the is continualy closed up.

[MidLandOne]

You cannot compare the performance of one insulation to another that is twice the thickness. That lack of understanding (and perhaps the cost??) is what likely led to your mistake of using too thin an insulation in the first place.

If you had used 1 inch thickness of Korex (ie the same thickness as the "polystyrene" you are comparing it too) instead of the 1/2 or 3/8 inch that you did you would have got a different result.

I have actually never seen any quality professionally finished boat insulated with less than 1" thickness of insulation regardless of type, whether that be Korex, Armaflex, or sheet or sprayed in foams. I would not specify thin 1/2 inch insulation, regardless of type, even for boats operating in the temperate and tropic regions.

Depending on hull construction (eg foam sandwhich requires less insulation) you may well have done better with thicker insulation than you now have as 1 inch is a minimum for any cruising area (assuming a boat is to be insulated), and so then been able to do away with the dehumidifier. I know of sail boats currently cruising in Cape Horn, Falkland, and South Georgia regions in both summer and winter and know of none that have required dehumidifiers (in fact most would not have the energy generation capabilities to run one) - they have suitable thicknesses of insulation and heated though, one of those boats being of foam sandwich hull construction that foam being the only insulation needed.

[Captn_Black]

On the subject of closed cell foam, I plan to use it in storage lockers to reduce noise and breakages. A big roll of 1/8" foam is really cheap and easy to work with. And on the subject of insulation, I also plan to attach permanent tinted storm windows over the top of the current ones, which as well as making them safer, will act as double glazing.

[Meridianpssg]

In reply to “MidLandOne” comments. It was never my intention to compare one insulation with another, rather sharing my at the coal face experience of using and experiencing the actual performance of the insulation products I have used. Whether they be the right choice for the job or not seems to be a matter of opinion even amongst the “professional” people in the industry.
I’m not sure the comment of a lack of understanding is a fair or accurate remark to make when one does not know the background experience of the writer. Also cost of Korex at time of purchase was never an issue. One can only assume you have never lived aboard a boat long term as your remark of ‘assuming a boat is to be insulated’ intimates to me you are saying maybe it’s not necessary? I on the other hand would be delighted if they mandated into law all boats have to be insulated when constructed, a job that would be so easy to do in the early stages of construction and a lot less costly than some of the unnecessary toys we throw heaps of money at with little home comforts afforded.
Salvaging a piece of the dumped Korex I can confirm it was ¾” thick. This product was decided on after a thorough research over two years visiting boat shows in New Zealand, always looking for the best product on the market for marine insulation. We settled finally with Korex and got all the ‘Professional’ advise at to what thickness we required, how to install etc etc. I do not profess to be an expert in insulation however having had 40 plus years in the construction industry and also building a boat I consider my practical knowledge and abilities sound.
The area of discussion regarding ‘professionally’ finished boats and the merits of adequate insulation of any thickness is a road I do not wish to travel having seen so many poorly finished poorly insulated professionally built boats! I guess for profit rather than long term quality, leaves me very cynical of the word ‘professional’
Our Whiting 45 was professionally built without any insulation at all, a decision I can only guess based on cost, and as the second owner I don’t know the real answer to that. The hull is solid GRP with ¾” marine ply topsides and decks all GRP coated and teaked over to deck sides.
After completing the Korex insulation in NZ we spent six years cruising the NZ coastline completing two full circumnavigations of NZ including Stewart Island in that time frame.
In the deep south of NZ we thought the Korex was coping fine in the cold (although at that time not living permanently aboard and taking no real note of performance I’m not sure if this is a fair assessment) and indeed in the early stages of our cruising life aboard in the tropics it was great. Our boat seemingly cooler inside than other cruising boats we came in contact with.
However we in NZ really have no appreciation of just how cold and damp it can be here in the high latitudes in the Northern Hemisphere. We spent 3 years in Japan and the problems with our Korex insulation started to show its failures there. Mildew and dampness in cupbds, running water down walls etc. We never had this experience in NZ. We were also told by the experts in NZ that any hull surface below the water line does not require insulation – our experience in NZ this was correct – Not so up here as our floor inside our boat is well below the waterline all the areas below the waterline not insulated just dripped with condensation – a problem we have now remedied.
Cold up here can be (we have had it) a foot thick of snow cover over your entire boat for a week or more then rain turning the last remnants of snow to ice which can last for days.
Our re-insulation with 1” R5 polystyrene has been a great success and the best thing we could have done, regardless of your comments being ‘minimal insulation’ it’s what a lot of boats here use and it works – we are living proof of that.
I personally would never be without a dehumidifier aboard a cruising live aboard boat regardless of how thick my insulation was. Your comments saying you know of plenty of boats that have not got nor require dehumidifiers are probably correct. However I have never met a cruiser yet who has purchased a dehumidifier say it was a bad investment, in fact like us they would never be without one aboard again having experienced first hand the difference it made to their living comfort aboard for a cost of around $180!
Condensation created by gas cooking, body heat/breathing etc in my opinion has little to do with good insulation, and more to do with dealing with warm humid air in a confined space with people living aboard. We have three expel air fans aboard which helps circulate and remove stale air but does not cope with condensation. Up here on houses with poor thermal glass insulation they apply a shrink wrap clear plastic to one side of the window (inside or out) with double sided sticky tape and just remove in the summer. We have done this process to the inside of all our windows with great success – no condensation to window glass! However as a test if we leave the dehumidifier switched off overnight our windows in our sleeping quarters are wet with condensation in the morning from body heat/breathing etc – wipe the shrink wrap plastic and the exterior glass is still clear. Having a dehumidifier running and this is just not an issue. The power consumption of a dehumidifier is very low. We can operate it with our 2.5kw inverter with no problem at all, albeit with all our other demands for power from our battery bank over a long period this becomes prohibitive. As we are always tucked in a marina over winter with shore power, running a dehumidifier 24/7 is not a problem. Any boat with a half descent generator aboard would cope with the power demands of a dehumidifier without compromising the power demands made on the genset for other requirements.
We keep our boat around 16-18c inside which is what we like. Of course we have the capability to have the interior a lot warmer if we desired.
I just don’t understand your remarks regarding sandwich hull construction as the only insulation needed. In Japan where the majority of Japanese sailing boats are of sandwich foam construction and the weather although very cold in the winter is not as cold as here in Alaska/BC. Our contact with Japanese cruisers in the winter all complained of wet cupbds, dripping ceilings and walls etc and on our advice some purchased dehumidifiers which went some way to alleviate their problems, but still wasting a lot of power heating their boats and not being able to retain that heat for lack of good insulation. Having not lived aboard a sandwich constructed boat I do not profess to really know the full story of sandwich foam as to its insulation qualities – but Japanese people are very particular about quality of products and their performance - they are not in my experiences impressed with sandwich foam as an answer to good insulation.
Again our experience says you need both, good insulation and a dehumidifier!
Up here where it gets really cold we feel bullet proof with this combination.
In summary I stand firmly to my statement of facts that polystyrene foam regardless of whether it is 1” 2” or even 3” thick glued with the compatible glue recommended and gaped at edges and joints, and filled with expanding insulating foam is far superior and easier to handle than Korex of the same thickness AND if cost is a factor in your equation Polystyrene beats Korex hands down!

[MidLandOne]

Originally Posted by Meridianpssg

In reply to “MidLandOne” comments. It was never my intention to compare one insulation with another...

But you did, you rubbished Korex, then in your current post you did so again. I won't address every point you make except-

Your single boat experience flies in the face of the experience of others who have seen the results over many boats with respect to use of Korex, Armaflex, foams, etc. It seems that you got poor advice regarding the thickness of insulation required but that only provided you had specified that you were going to operate the boat in high latitudes for extended periods of time - but none of that is the fault of the material used.

You say you have a Whiting 45 - I am familiar with Paul Whiting's designs and while fine boats for temperate, etc regions I would be surprised indeed if your Whiting is anything close to being a good choice of boat for high latitude cruising or living aboard. You probably made a not very good choice of boat if the intention when it was purchased was high latitude cruising or living aboard in comfort.

Your comment that all boats should be insulated is not viable. The majority of boats that are cruised do so in the temperate and tropic zones for which insulation is not required for most hull constructions (metals being an obvious exception). Furthermore, most boats are never cruised or lived aboard they being day sailed or perhaps cruised locally for a few days or weeks a year. Apart from anything else including cost, the insulation would be uneccessary added weight to carry around for the life of the boat. If you want a boat for extended high latitudes cruising then get one that is or can be prepared for that.

The foam sandwich hulls of boats with which I am familiar and prepared for high latitude cruising have all been custom design and builds with insulation in mind (and they were also foam sandwhich below the waterline which many production yachts are not). If one wants to live or cruise a cheap production sail boat (all of which are designed with tropics to temperate regions in mind) in high latitudes you are going to have problems of many sorts, insulation being only one even if foam sandwich. I did not think anyone would extrapolate my foam sandwhich hull construction comments as including the light scantling typical cheap production yachts meant for temperate and warmer sailing.

Again, I would suggest that others take your single experience comments on board but note that they are just that a single and narrow experience and are at odds to the general experience with such materials. My suggestion would be to get very good professional advice from a designer experienced in preparing boats for high latitude operations and that advice will go far beyond just insulation requirements (eg heating, ventilation, surface finishes, hatch and port selection and preparation, ...) if you want a comfortably inhabitable boat.

[Cheechako]

Oh yes... the theory vs the reality. I once fell into the "Vacuum sealed metal panels" hype for refrigeration. After a lot of money and work .....In the end there was no noticeable differnce in the running time of my engine to recharge the battery banks... and that is the bottom line isnt it?

[MidLandOne]

Originally Posted by Cheechako

I once fell into the "Vacuum sealed metal panels" hype for refrigeration...

As they say, there is a sucker born every minute and they are magnetically attracted to salesmen whose only concern is to get their money .

Have you tried adventures with the likes of fuel cells, cold fusion, magnetic anti diesel bug devices yet? Plenty of adventures left to try if you haven't .

John

[Cheechako]

Oh, yes, I'm working on the highly touted cold fusion magnetetic reverse fuel usage rejuvenator as we speak,,,

[MidLandOne]

Am away on the boat at the moment but as its laundry day today am trying to keep out of trouble. So to look too busy to help with laundry I've hunted out a some conductivities for some materials.

The thermal conductivity of various insulations used are (all in W/m.degK, lower numbers are the most insulating) -

Armaflex 0.038
Korex 0.034
Rigid Polyurethane 0.020
Polystyrene (R5) 0.020

So all much of a muchness and if one finds one is greatly different to another after installation then one has done something wrong.

While slightly greater thicknesses of Korex and Armaflex are required for the same level of insulation they are both guaranteed to be self extinguishing, whereas polyurethane and polystyrene will at best be flame retardant providing a flame retardent has been added. Polyurethane and polystyrene once burning burn with toxic (like fatal if cannot get away quickly) fumes.

Polyurethane also should be installed with a vapour barrier and, in my experience, to control dust fretted off it.

In my experience, despite their slightly higher conductivity, Armaflex first (which has the highest conductivity) and then Korex which are both nitriles are the products of choice in high quality boats and that most likely driven in the main by their guaranteed self extinguishing properties (guaranteed because they are a specific product, not one of a wide family of products whose specific natures are not necessarily consistant). I have never had occasion to test this but I would expect that wide use, such as hull insulation, of polyurethane or polystyrene would not be accepted in a boat going into class.

In the end, if you cannot get any specific one of these products to work then you have done something wrong - it is incorrect to claim that any one of these is inferior from the straight conductivity point of view as in that department they are all much of a muchness. The nitriles have the significant advantage of fire safety and ease of installation (especially on curved surfaces), long life (especially over rigid polyurethane) but at a monetary cost. They also maintain their vapour barrier properties even if their surface is damaged.

Amateur boats often use sprayed in foams, a practice I would personally stay away from - apart from it making it difficult to release space behind linings in the future if found wanted without a carving expedition I have seen it burn .

[Cheechako]

Great info, however, in my opinion the whole burning issue is bunk. If you are inside a boat that is burning more than a matter of seconds you are in trouble anyway. I have seen fibreglass boats burn to the waterline and you dont want to anywhere near the smell even when outside. If the fire has burned through your covering, be it teak strips or carpet, and you havent abandoned ship, you are gone anyway.....