Are Cats Made from Duflex Panel Kits Strong ?

[beiland]

Originally Posted by sparau

If true what is the world coming to where we smash 50,000lb of non recyclable, non renewable boat for being "scratched and water damaged".

I wondered about that description myself. I wonder if there is any other way to verify such a story.

But then again I would have a serious doubt that the Nidacore people of that era would have put a bold 'mistruth' in their literature that many would question. Were it false information it surely would have damaged their reputation, and made folks wonder about all of their other claims.

[colemj]

Originally Posted by Factor

Is there a single designer who is prepared to specify Nida Core?

genuine question.

I don't know about the present, or for custom builds, but in the past Manta and Catana built boats using solely Nida Core.

Mark

[smj]

Originally Posted by colemj

I don't know about the present, or for custom builds, but in the past Manta and Catana built boats using solely Nida Core.

Mark

But didn't Manta go to core cell in their later boats? And why?

[colemj]

Yes they did. So did Catana. I presume it was because core cell is stiffer for the same weight so they could make either a stiffer boat or a lighter boat.

Mark

[44'cruisingcat]

Originally Posted by beiland

So I posted this previously




BIG BANG #2, catamaran drop test


A customer of the NidaCore Corp, in the Caribbean islands had a 65' commercial charter boat, cored entirely with NidaCore poylpropylene honeycomb (less the hull bottom), including hull sides, deck and superstructure. It was scratched and water damaged on a coral reef during a major hurricane. The insurance copany agreed to write off the boat on condition that customer takes boat out of service and does not attempt to repair it. The charter boat operator agreed to dismantle the boat and discard of it.

Using one of the marina's cranes, they hoisted the 50,000 lb boat 50 feet in the air and dropped it onto a concrete parking lot, hoping that they would be able to collect the pieces and discard of them in the dumpster. To much of their astonishment the boat remained completely intact, with no visable structural damage. They repeated the procedure continuously for a couple of days to no avail. Finally to accomplish their mission they had no other alternative than to rent a chainsaw to cut the boat into pieces.


Although somewhat of an extreme example, it clearly indicates the superior nature of a 'resilient' cored-sandwich construction in boats. The increase in impact strength as compared to single-skin laminates is better demonstrated if one sees the core as a shock absorber that evenly supports the outside skin from impacts and protects the inside skin, while still having enough elasticity maintain the bond line between the core and the skins. Experience shows that although sandwich construction is not completely punture proof, it significantly increases skin penetrating puncture resistance.


The more brittle cross-linked PVC and SAN foams would simply crumble and shear under a sever impact whereas polypropylene honeycomb cored structures would be locally damaged, however the core structure would be intact, and cells, although elongated would still keep their structure and shape, ready to absorp or withstand more impacts and compressions.




Brian's NOTE: I have not personally verified this report. It was printed in a in sales manual/spec sheet document passed out by NidaCore corp.

And you BELIEVE this????? And after the first day, nobody though to take video of this extraordinary event??? The toughest material ever made?

Also, why wouldn't the insurance company sell the "wreck"? If the boat was only scratched, they could have sold it for a considerable sum, and reduced their payout. An insurance company that throws money away?

Sounds pretty fantastic to me.

Again, all I can suggest is you GET SAMPLES. If this stuff is as tough as they claim, you'll know the moment you pick it up. I can tell you from using it, that it's not. Not even remotely close.

The material we've used, I could in less than 10 minutes, reduce a 300mmx100mm piece to core using nothing more than my bare hands.

[aclmck]

Originally Posted by 44'cruisingcat

And you BELIEVE this????? And after the first day, nobody though to take video of this extraordinary event??? The toughest material ever made?

Also, why wouldn't the insurance company sell the "wreck"? If the boat was only scratched, they could have sold it for a considerable sum, and reduced their payout. An insurance company that throws money away?

Sounds pretty fantastic to me.

Again, all I can suggest is you GET SAMPLES. If this stuff is as tough as they claim, you'll know the moment you pick it up. I can tell you from using it, that it's not. Not even remotely close.

The material we've used, I could in less than 10 minutes, reduce a 300mmx100mm piece to core using nothing more than my bare hands.

Couldn't agree more i think story telling comes into play here the product can be pulverised in a few minutes to fit in a bin with only my boot and hands, but a while since i used it and maybe the product has been altered???

[44'cruisingcat]

So many holes in this story. You'd need a BIG (expensive) crane to lift a 10 ton boat 50 feet, then a REALLY stupid crane driver to agree to drop it. You'd have to be expecting a boat that size, dropped from that height, to explode in a huge shower of shattered fibreglass - who'd be dumb enough to expose an expensive crane to that?

Also, after paying a crane that size for whole day, which would cost a fortune, and achieved no success, who'd be dumb enough to hire it again for a SECOND day?

Then when it was dropped, what happened? Did it bounce? How high, how many times? That's a hell of a lot of kinetic energy - it had to go somewhere.

Even if the core was elastic enough to survive, the fibreglass skins certainly wouldn't.

Fantasyland.

[44'cruisingcat]

Originally Posted by beiland

Were it false information........... and made folks wonder about all of their other claims.

Yep, it's certainly got me doing that!

[beiland]

Originally Posted by 44'cruisingcat

So many holes in this story. You'd need a BIG (expensive) crane to lift a 10 ton boat 50 feet, then a REALLY stupid crane driver to agree to drop it. You'd have to be expecting a boat that size, dropped from that height, to explode in a huge shower of shattered fibreglass - who'd be dumb enough to expose an expensive crane to that?

Also, after paying a crane that size for whole day, which would cost a fortune, and achieved no success, who'd be dumb enough to hire it again for a SECOND day?

Have you been to the Caribbean islands....ha...ha. There are any number of 'characters' down there that might have tried this....ha...ha

Even if the core was elastic enough to survive, the fibreglass skins certainly wouldn't.

Fantasyland.

Well I put a notice on 4 different forums to see if we could flush out any more details on this. I also sent an email to the guys down at Gold Coast Yachts to see if they knew any more details.

Forum posting like this.....

Big Catamaran, Big Drop 'Test',....WHAM !!
The following quote is taken from a piece of literature (manual) that was utilized by the NidaCore company as a sales pitch in support of their PP honeycomb core product.

that Nidacore claim

There are no other specifics supplied,...such as name of vessel, charter organization, island location or marina where this was carried out, what hurricane, etc. And it may have occurred before wide spread info dissemination by the internet came into being?

Is there anyone with any more knowledge as to the details of this 'event' ??

[aclmck]

IF the story were true it must be a mother of all cranes that can be used around a dock and actually let go 10 tonnes this is a feat in itself, the crane must be pretty big and built like ****** . Cranes don't normally react well when loosing a load (don't ask) the forces on this would have such a whipping action a small crane up to 80-100 tonne would not handle once let alone several times over a few days.

saw a tower crane after it whipped lashed itself (driver drove it hard into its stops to get a can of coke into the cabin) it had to have the boom replaced. seen many others flip over after loosing loads so find this story just that a story.

[beiland]

Okay I'm going to skip over more discussions of this 'story' on this subject thread until we can find other details. As I said, I put a posting on 4 other forums to see what we might find out,...under its own specific heading.

Originally Posted by beiland

Well I put a notice on 4 different forums to see if we could flush out any more details on this. I also sent an email to the guys down at Gold Coast Yachts to see if they knew any more details.

Big Catamaran, Big Drop 'Test',....WHAM !!

[beiland]

There have been a number of questions brought up about the feasibility to perform resin infusion on PP cored panels,...about how the resin might penetrate the hollow cells, and/or the skins might be starved of proper resin amounts??

I just found this:
Infusion Grade PP Honeycomb

Utilizing a composite surfacing material, the open cell structure in Infusion Grade PP Honeycomb is sealed, thereby allowing the flow of resin during processing to remain at the bond line with minimal penetration into the honeycomb core. The veil provides a continuous substrate for 100% adhesion to the panel skin material. The core does not incorporate any flow paths, so a careful selection of glass reinforcements that have a resin flow path capability is required. To help facilitate a uniform flow of resin through the sandwich structure, additional pass through holes are added to the honeycomb that pierce the surfacing material at one cell and allow resin flow from top to bottom of the sandwich. Spacing of these holes is typically 4" on center.

Infusion Grade PP Honeycomb features a composite surfacing material that is compatible with most laminating resins.

What intrigues me most about this is suggest that Kelsall's table methods could be employed with PP core in addition to his specs of only foam. Kelsall's method gives you a smooth outer skin requiring no extra fairing as do most of the other 'panel methods' that need additional glass reinforcement on the skins.

[beiland]

I see that I never followed up with new information on this subject thread. So I will open old wounds

OK here is the latest info I can uncover. This was sent to me by a gentleman working for nidacore division of 3M

I'm not sure which "drop test" he's referring to. If it is Janot Lemaire's catamaran, it was not a test. The vessel was torn from it's mooring during a hurricane (I believe in the Bahamas because that's where he called me from to order more core and told me what had occurred). The vessel sat on a reef and chewed up the keels and then beached at some resort.

The owner of the resort wanted the vessel cleared off the beach immediately. Janot brought in a crane and spent quite some time (he said three days) picking it up 15 feet off the ground and dropping it to try to break it up. He said it just bounced so they finally resorted to cutting it up with chainsaws.

Mr Lemaire built quite a fleet of these Seminole Cats for Club Meds as well as some others for customers in the Middle East. They had a reputation for being a very tough boat.

Any other info would have to come from Janot Lemaire. I have not seen him in at least ten years. He moved to maybe Guadalupe and then possibly Tahiti where his brother was operating some boats. Everything I know of it was related to me by Janot in that phone call. I believe that was around 1993 or 94

I found these photos of one of his vessels,...I believe the one in the Bahamas

[beiland]

....mitigating impact loads (from another forum discussion of this incident)

Originally Posted by "karo1776

Brian... many years ago... now 32... a company my brother and I owned experimented with a cored graphite skin structure for wings (aero not water). The idea was to allow an internal mechanism change the wing shape and also as impact improvement for small stones kicked up on landing a takeoff landing.


Anyway, we experimented with several layup designs all with resin contents of 27-32% resin (epoxide) to skin material (less core) mass. We found that thin carbon composite skins with a polyethylene foam core of about 4-8 lbs per cubic foot were very good... now what was interesting is it was extremely impact damage tolerant and had good rigidity for the use... note these core thicknesses were in the range of 0.1" to .2" for reference.


Now later some work was done with similar materials for survivability proposes... very good to its limits.


What was strange was the flexible core would transfer the impact loads and protect the skins from localized impact damage...


JUST LIKE YOU TALK ABOUT HERE... !

[StuM]

Originally Posted by beiland

I see that I never followed up with new information on this subject thread. So I will open old wounds

OK here is the latest info I can uncover. This was sent to me by a gentleman working for nidacore division of 3M

I'm not sure which "drop test" he's referring to. If it is Janot Lemaire's catamaran, it was not a test. The vessel was torn from it's mooring during a hurricane (I believe in the Bahamas because that's where he called me from to order more core and told me what had occurred). The vessel sat on a reef and chewed up the keels and then beached at some resort.

The owner of the resort wanted the vessel cleared off the beach immediately. Janot brought in a crane and spent quite some time (he said three days) picking it up 15 feet off the ground and dropping it to try to break it up. He said it just bounced so they finally resorted to cutting it up with chainsaws.

Mr Lemaire built quite a fleet of these Seminole Cats for Club Meds as well as some others for customers in the Middle East. They had a reputation for being a very tough boat.

Any other info would have to come from Janot Lemaire. I have not seen him in at least ten years. He moved to maybe Guadalupe and then possibly Tahiti where his brother was operating some boats. Everything I know of it was related to me by Janot in that phone call. I believe that was around 1993 or 94

I found these photos of one of his vessels,...I believe the one in the Bahamas

So that 50ft drop has now become 15ft. That's a lot more believable.

And is the cat in those pictures going to be 50,000lbs after it's been stripped of engines etc so that it can dropped to break it up? I doubt that.