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Random Quote: Boatowner's prayer. Please dont let my widow sell my gear for what I said I paid for it.
Is GRP made with EPA compliant resin sold after 2002 really not as strong as those made with resin sold before 2002?
Was reading Dusky hull cracking thread when I came across this quote from "bluelight special":
"Prior to 2002 all our boats were built with no "lateral supports". Again thousands of boats were built this way with no issues such as the one Louis is experiencing. The "lateral supports" that Louis is referring to in our current construction were added in 2002 to compensate for the change in the resin and styrene that was mandated to stay compliant with EPA standards."
His post suggests he is connected to Dusky and has knowledge of the design modification.
Is this legit? Did other manufactors change their design?
He is the "NO man" I spoke to at Dusky, but they can't seem to get their story straight. I was led to believe that pre-98 hulls weren't made with any lateral supports.
Regardless, they are trying a half ass solution to fix a major design flaw. My fiberglass man says their lateral supports won't give much support at all. If you look at the pictures on their website, these lateral supports don't even come all the way up to the floor. They will only hide their problem for a few more years or until the second owner, then they don't warrantee.
The correct way to do it is with 2 more longitudinal stringers.
I read that post also. I think it is a half truth.
MACT compliant (maximum achievable technology) resins in the lower cost spectrum, generally speaking, have a lower elongation. Elongation is the "stretch" that the resin will allow before failure, expressed as a percentage. It is a measure of a resin's toughness or brittleness.
As the resin stretches, it allows the glass fibers to take the load. Obviously, if the resin has high elongation it will allow the fibers to do their job better. If the resin has low elongation it can fail before the fibers have a chance to come into play. If the fibers don't take up the load, then the resin must take up the load. Resin is not meant to be load bearing.
The half truth part is that, yes, they probably did change resin to be MACT compliant, but the resin they previously used probably had about the same elongation as the new MACT resin. Most earlier polyester resins have an elongation of 2-4%. Most MACT compliant polyesters that I've seen have elongation of 1-3%. Glass fibers should come into tension within that average percentage even after considering fiber crimp. As a side note vinylesters have an elongation of 6-9%, making them much tougher.
As I stated in the other thread, fatigue failure is the likely culprit on Louis' boat. The panels flexed back and forth until the resin and glass gave up. If Louis' boat was built with pre MACT resin, then a post MACT boat could be expected to crack a "little" sooner if the construction remained the same. I suspect the change in construction had to do with more than just a resin change.
Disclaimer: If you see emoticons, that means the above is written in jest. It is for entertainment purposes only. It is not meant to represent any actual persons, places, or things. It is the opinion of the poster that it is funny. Your opinion may vary. No animals were harmed in the typing of this post but a few egos may have been bruised.
Why would I want to buy a boat that is using "newer technology" to eliminate critical structural members from its design? I can understand using a stronger fiber/resin system, then perhaps using less layup because of that, however removing critical transverse elements? Pure hog****. How much money did they save by not integrating bulkheads? The answer: much less than what I would have paid knowing it was built right. Beware of these companies using excuses with new/lighter/stronger technology to cut corners in design. I like my boats solid, full of glass fiber with complete encapsulation. I challenge any of you to find a high-end boat builder who designs their hull structure the same as what Louis has shown in his Dusky. Good Luck.
As I stated in the other thread, fatigue failure is the likely culprit on Louis' boat. The panels flexed back and forth until the resin and glass gave up. If Louis' boat was built with pre MACT resin, then a post MACT boat could be expected to crack a "little" sooner if the construction remained the same. I suspect the change in construction had to do with more than just a resin change.
If the transverse structural elements were there, there most likely would not have been an issue with hull cracking. That's the point. How much weight and money are they saving by removing them? Probably as much as two full tackle boxes on weight, and less than that in cost.
Why would I want to buy a boat that is using "newer technology" to eliminate critical structural members from its design? I can understand using a stronger fiber/resin system, then perhaps using less layup because of that, however removing critical transverse elements? Pure hog****. How much money did they save by not integrating bulkheads? The answer: much less than what I would have paid knowing it was built right. Beware of these companies using excuses with new/lighter/stronger technology to cut corners in design. I like my boats solid, full of glass fiber with complete encapsulation. I challenge any of you to find a high-end boat builder who designs their hull structure the same as what Louis has shown in his Dusky. Good Luck.
$4000 seems to come up a lot...
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I think you may be misinterpreting what I wrote. First, Dusky was probably mandated by EPA rules to change to a MACT compliant resin. I'm not saying this was a change that they decided to do to save money or make the boat better. On the contrary, I was illustrating the point that they were using it as an excuse for adding bulkheads to the boat, bulkheads that probably should have been there all along.
New technology has nothing to do with with it. It is the unsupported panels that deflect until failure. Failure is almost assured with either resin. Dusky built the boats as they deemed fit. I'm sure they thought they were okay. Only many years later did the problems with Louis' boat appear. Perhaps they think this is acceptable, perhaps they are trying to dodge a bullet.
From a practical standpoint, some "newer technologies" allow for weight savings but rarely ever cost savings. What you consider "critical structural members" may not be necessary depending on the design and materials used. Your approach is a little too simplistic. When boat building shifted from wood to composites many "critical structural members" were left out. Because they could be.
Dusky is certainly not using newer technology in the classic sense. They are building boats as they always have, albeit with a new type of resin. They may have made some structural changes but it is basically the same construction methodology.
I think we are on the same side as it pertains to the construction of Louis' boat. I do differ in that Dusky has a written warranty that they are sticking with, regardless of the damage to their reputation. That is their prerogative, good or bad.
Disclaimer: If you see emoticons, that means the above is written in jest. It is for entertainment purposes only. It is not meant to represent any actual persons, places, or things. It is the opinion of the poster that it is funny. Your opinion may vary. No animals were harmed in the typing of this post but a few egos may have been bruised.
MACT compliant resin would have nothing to do with this failure. This is the classic case of either a change in laminate or redesign of the stringer system. Where is the failure located? Are the cracks running longitudinal or transverse?
I'm gonna go with laminate change as Dusky seems to have removed a layer or two to save on cost. When doing this all Dusky had to do was add a few small (4"x4") transverse beams to break up the panel size as full bulkheads would not be required.
When Whaler was refreshing/updating the Sea Pro Bay Boats they took some cost cutting measures by removing 2 layers of laminate from the hull bottoms. Whaler's engineers ran the numbers & felt there was sufficient laminate left for structure. During water testing prior to full production of the bay boats it was found that ALL 3 models had extensive longitudinal cracking in the hull bottom. They added a layer of laminate back in & added localized stiffiners (pre formed beams).
Keep in mind, a laminate that is 2x as thick as another is 8 times as stiff. Laminate can be made too stiff, however.
The EPA has not ordered a particular boatbuilder to become MACT compliant, it was a standard that went into effect that ALL builders have to adhere to. In doing so, the resin companies reformulated resins and gelcoats so that they are MACT compliant. The major difference in the formulations are that the styrene content, which is a chemical component of the resin, has been lowered. The goal of this was to reduce emissions as during the chemical reaction that takes place when you mix resin and catalyst is that styrene is emitted. The problem with the standard for boatbuilders is that the higher styrene content of the resin, the better the laminate strength. Lower content means you cannot lessen the amount of laminate or reinforcement without seriously raising the possibility of failure.
Resin change in 2002 lead to Dusky design change? 
