Open or Closed Cell Foam in c.1979 Boat

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Nsp
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Open or Closed Cell Foam in c.1979 Boat

Postby Nsp » Tue Jan 08, 2019 9:58 pm

Is the foam used in 1979 to make Boston Whaler SPORT 13 boats open-cell foam or closed-cell foam?

I don't know if my 1979 SPORT 13 hull is heavier [now than when it was made].

jimh
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby jimh » Tue Jan 08, 2019 10:44 pm

What is the difference between open-cell foam and closed cell-foam?

Is there some way you make foam one way and not the other? I would ilke to get more information from you on these two types of foam, how they are made, and how they differ. Thanks.

As far as has been known and determined by actual chemical analysis of the foam used in a Boston Whaler boat, the foam has been the same type of foam for decades. As far as I can determine, "foam" as in foam made by chemical reactions of two liquids that hardens into a solid medium with entrapped air in small bubbles must consist of small air bubbles suspended in a solid. If you have a solid material that has no closed cells of entrapped air but has a porous nature, you call that a "sponge" not "foam." Since Boston Whaler has been making boats with their Unibond process, to the best of my knowledge, they have always filled the hull with foam and not with sponges.

If you think your Boston Whaler boat hull has entrapped water, see the FAQ for some advice.

Q3: Is There Water In My Hull?
http://continuouswave.com/whaler/reference/FAQ/#Q3

The FAQ answer will give you methods to use to determine if your Boston Whaler boat has entrapped water in the hull.

dtmackey
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby dtmackey » Wed Jan 09, 2019 8:17 am

This video may help answer some questions on how Whaler builds boats.

https://youtu.be/WNGx77-2WWI

D-

jimh
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby jimh » Wed Jan 09, 2019 6:31 pm

DT--the presentation on youTube you have pointed to is very interesting. It reveals some further details of the construction process of which I was unaware, specifically the paste of resin and chopped fiber applied to one of the two components of the Unibond hull to ensure a good bond when the two parts are joined.

I have visited the Boston Whaler plant in Edgewater, Florida, and was afforded a tour of the plant. I wrote a detailed article with illustrations about that experience, and published it at

BOSTON WHALER FACTORY TOUR
http://continuouswave.com/whaler/reference/factory.html

Because of the time of day when we were on tour, we did not get to see the process of the hull and liner being married together and the introduction of the foam. (The first shift had done its last boat, and the second shift was just coming on duty and had not made it first boat yet.)

In the present-day facility the creation of the foam is done under much more controlled conditions that in 1979. As seen in the recorded presentation (but not too well explained), a rather sophisticated machine controls the foam "shot" to a predetermined amount for each model of hull. The narration track is a bit misleading, as the material injected by the machine is not a foam, but rather a liquid mixture. The reagents in the mixture undergo a chemical reaction that turns them into a foam, filled with encapsulated bubbles, which expands significantly. It is important to note that the tightly clamped mold halves resist the expansion of the foam, helping to maintain the density to a higher weight. At the same time, intentionally designed vents in the molds, along with a setting of the mold forms at particular elevation angles, helps to distribute the foam throughout the empty space between the hull and the inner double-bottom hull liner. The hulls remain in these mold sets, and the foam is allowed to set and harden for many hours, before the newly joined hull are separated from the mold. The result is a very high consistency in manufacturing of the Unibond hulls.

Although my article does not contain any motion-picture elements, it does have a considerable amount of information and detail about the method used to construct Boston Whaler boats, so I would not hesitate to recommend reading it to learn more about how Boston Whaler boats are built.

Mr 88
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby Mr 88 » Thu Jan 10, 2019 9:40 pm

Having Googled open cell foam vs closed cell foam, I see there is a difference ,mostly in density and R value. So there is a difference in the two.

jimh
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby jimh » Thu Jan 10, 2019 9:50 pm

What is "R value" of foam? Are you talking about the insulation rating of foam with regard to conduction of heat? That is meaningless in the use of the foam as a medium to fill the space between the hulls of a Boston Whaler boat.

How is density related to "open" or "closed" cellular foam? It would seem to me that foam density is a function of how much air (or other gaseous compound) is trapped in the bubbles in the foam in a particular standard volume. Since the solid cured material that makes the foam weights more than the gaseous compound, the more entrapped bubble volume the lower the density.

But I still don't understand what the terms "open-cell" and "closed-cell" mean, and how you make different kinds of foam. Can you explain that?

Mr 88
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby Mr 88 » Thu Jan 10, 2019 10:13 pm

Just Google it as I did. Many of the aricles go into great detail. All I would be doing is copying and pasting .as I am not expert in this field.

dtmackey
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby dtmackey » Thu Jan 10, 2019 10:26 pm

Mr 88 wrote:Having Googled open cell foam vs closed cell foam, I see there is a difference ,mostly in density and R value. So there is a difference in the two.


Yep, the web is loaded with information on spray foam used in homes and that's where "R" value comes into play. Open and closed cell foams have with very different insulation and property characteristics.

Closed-cell is a lower density foam (2 to 3-lbs-per-cubic-foot) and open-cell even less (0.5 to 0.75-lbs-per-cubic-foot). Since there is no structural strength required in wall insulation between supporting 2 x 4 or 2 x 6 construction, these foams work just fine. Open cell foam is a very poor performing material for strength.

In boats, foam can also be sprayed, poured, or injected into the desired area. The density of the foam can range from 2 to 16-lbs-per-cubic-foot. The foam density is selected depending on the application and strength required.

I'm not aware of open-cell foam ever being used in the marine setting. I have only encountered closed-cell in the boats I've owned or rebuilt over the years.

Two-part polyurethane closed-cell foam strictly for flotation [has a density of 2-lbs-per-cubic-foot]. When strength is required [a foam with a density of 4-lbs-per-cubic-foot] or greater would be used.

The "weight" of foam is based on what one-cubic-foot of fully activated and expanded foam weighs. For comparison, a cubic foot of water weighs 62-lbs.

D-

jimh
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby jimh » Fri Jan 11, 2019 3:38 pm

DT--I deleted all the hash marks or octothorpe characters from you post because they are never used here to mean pound-avoirdupois.

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Re: Open or Closed Cell Foam in c.1979 Boat

Postby jimh » Fri Jan 11, 2019 3:53 pm

The comparison of the density of a typical foam with water is very cogent. What makes a Boston Whaler boat "unsinkable" is not that the foam would float, but that the foam fills up a very considerable interior volume of the boat's hull, and by occupying that space it prevents water from occupying it. When a Boston Whaler boat hull fills up with water, the amount of water that can be held by the empty space below the top of the gunwales is limited; much of that space is filled with foam, which, as mentioned, has a much lower density than water.

Probably the best example of how a Boston Whaler boat can not sink is found in the OUTRAGE 25. It has a relatively deep-V hull, and most of that hull space below the level of the deck is filled with foam. This gives the hull form tremendous reserve buoyancy. The OUTRAGE 25 hull has 9,000-lbs of "Swamped Capacity." That means that even with the hull filled with water to the gunwale tops, you could add 9,000-lbs more weight before the hull would sink, that is, before the weight exceeded the buoyancy of the hull form displacing water.

jimh
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby jimh » Fri Jan 11, 2019 6:12 pm

Mr 88 wrote:Just Google it as I did.


I searched GOOGLE.COM for "it" and got 25-million results. I can't read 25-million search results to figure out what you mean. Please be more specific.

It is not up to readers to to clarify the terms you are using. If you throw out some terminology, be prepared to explain it. To require that someone else has to explain the words you are using is not a reasonable basis for you to use those term. If YOU don't can't explain them, then don't use them.

I am still waiting to learn from people using terms like "open-cell foam" exactly what that means and how it is different from "closed-cell foam."

And how do you make open-cell foam?

How do you make closed-cell foam?

What is the chemical basis for these to be different?

So far nothing from anyone about this that has used these terms. Is this some sort of secret code word? Please explain. You all presume that there is universal knowledge and common understanding of these terms. They are tossed out there like every reader is expert about them.

Paul A
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby Paul A » Sun Jan 20, 2019 12:33 pm

Another factor may be the "perm rating" or the amount of moisture that gets through or into the material. I have been told Boston Whaler foam is and always has been closed cell which should have a very high "perm rating" but the foam still holds water like a sponge if subjected to prolonged periods or can have condensation build-up with a boat sitting in cold water but high air humidity. The air hits a dew point somewhere in the hull possibly causing water vapor condensation in the foam.

jimh
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby jimh » Tue Jan 22, 2019 9:11 am

Paul A wrote:Another factor may be the "perm rating"...

I have to infer that "perm" in your term "perm rating" must mean permeability. Was that what you intended?

Where do you find a definition of "perm rating" and a listing of the "perm rating" of various materials?

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Re: Open or Closed Cell Foam in c.1979 Boat

Postby jimh » Tue Jan 22, 2019 9:12 am

Paul A wrote:...Boston Whaler...foam...holds water like a sponge if subjected to prolonged periods...


Prolonged periods--of what?

Many years ago I had a sample of foam from a Boston Whaler boat. I immersed the foam in water and held it in the water for weeks. Then I removed the foam sample from the water. The foam was dry and held no water.

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Re: Open or Closed Cell Foam in c.1979 Boat

Postby jimh » Tue Jan 22, 2019 9:13 am

Paul A wrote:...Boston Whaler....foam...can have condensation build-up with a boat sitting in cold water but high air humidity. The air hits a dew point somewhere in the hull possibly causing water vapor condensation in the foam.


How does outside ambient air enter the sealed interior of a Boston Whaler Unibond hull?

In the production process, any sprue holes in the boat are covered with resin and sealed. Exactly how does air enter the sealed Unibond hull interior? And, if air is free to enter the sealed interior by some access point, would not water be able to enter that same access point? I don't believe there is such an access point. The hull and inner liner are sealed, and the only way air or water can enter is by damage or by osmosis through the fiberglass resin layers.

dtmackey
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Re: Open or Closed Cell Foam in c.1979 Boat

Postby dtmackey » Tue Jan 22, 2019 11:09 pm

jimh wrote:
Paul A wrote:...Boston Whaler....foam...can have condensation build-up with a boat sitting in cold water but high air humidity. The air hits a dew point somewhere in the hull possibly causing water vapor condensation in the foam.


How does outside ambient air enter the sealed interior of a Boston Whaler Unibond hull?

In the production process, any sprue holes in the boat are covered with resin and sealed. Exactly how does air enter the sealed Unibond hull interior? And, if air is free to enter the sealed interior by some access point, would not water be able to enter that same access point? I don't believe there is such an access point. The hull and inner liner are sealed, and the only way air or water can enter is by damage or by osmosis through the fiberglass resin layers.


I'm scratching my head on this one as well. Condensation on a hull from cold water on one side and warm humid air on another is one way to get condensation, but a Whaler hull is sealed and not pulling in humid air for this to happen. I'd discount this since altogether.

Whaler hulls I've seen that are waterlogged are due to damage of the outer skin or the brass drain tubes. In the salt the electrolysis eats them up if the boat is in a marina with stray dock current, but even without current, they get thinner over time and fail. Because of this, I put a drain plug in the inner and outer drain tube holes to prevent salt water from entering in the first place and rely on a rule pump in the boat to remove the excess water.

D-