Are Cats Made from Duflex Panel Kits Strong ?

[cat man do]

Originally Posted by beiland

...a liitle confused again, perhapos someone can provide additional info?

What is the distinction between?

Polycore Products
Polycore Composites - Polycore Australia - Polycore Honeycomb


...and
Australian Composite Panels
Australian Composite Panels - Lightweight Fibreglass & Honeycomb Materials


both polyproplene honycomb products

Same same but different.

I think you will find Polycore is the supplier of the core material to ACP.
ACP manufacture panels using Jamac epoxy resin (also sold by polycore) making a finished product which is sold by ACP as well as Polycore .

[beiland]

Originally Posted by cat man do

Same same but different.

Thanks, it was not long after I made that posting that I found ACP in the 'most favorite' link section of Polycore.

[beiland]

Hello Cat Man Do.

How is your 50' powercat project coming along? When might you expect to get her in the water for a little sea trial?

Looks like quite a nice design. Who's hull bottom did you choose? And what basic hull construction materials?

Perhaps you have already posted much of the info? If so just lead me to that discussion.

Much obliged....and have a great new year.
Brian

[beiland]

After visiting this subject thread, geeting involved with some of the subject matter, and doing some more reading on Propropylene honeycomb materials, I've become a convert to this PP panel material.

....so much so I'm am exploring the possiblity of building steel hulls with PP cored panels as decks and superstructure

http://www.cruisersforum.com/forums/...ml#post1266080

[44'cruisingcat]

I can only suggest you get some material samples and check them out before committing. I'm working with some polypropylene honeycomb cored glass panels right now, (using them to build internal furniture) and there is no way I'd use them for anything structural. The core to laminate bond is feeble - you can almost peel the glass off like peeling an orange- and panel stiffness isn't impressive.

[beiland]

1) Building a bulletproof boat
Building a bulletproof boat

....this gentleman was successful with applying a 3 inch Nidacore reinforcement to the hull skins of his 65' Alden Schooner

2) I have a 27' foot cc with the entire deck in nida-core. The deck top was covered with extra glass. I did not do it. So, I don't know what was used. But-it is thin. It was done in 2003. The boat resided in S. Fl. until this year. NO PROBLEMS at all. It is now standing up to freezing temps.

By the way I have a a large hatch (3 X 2') that I stand on--no flex. The only support is the frame. I have had some heavy weights on the boat regularly. Also, my T-top is Nida core. With proper support it is tough stuff. The only draw back is that the edge of my T-top looks rough because you can see the cells (up-close anyways) I plan on attaching a rope or rub rail on the outer-edge in Feb.
anyone use nida-core factory panels for deck replacement? - The Hull Truth - Boating and Fishing Forum

3) We use them for deck stingers and bulkheads in some of our 23' with zero problems . we get the factory installed 1808 skin on both side and we have about a 30" span from chine to stringers, this being said I can't stress enough how important it is to tie both edges together in all directions so that the glass completely encapsulated the core material

4) This guy built a whole catamaran out of it
http://buildacat.com/lyra1.html

Building a cat



....from one of the forums....
A few hints about nida core. When using the non glassed ( I have not used the glassed) you need to paint the scrim skins with resin first or the scrim will rob the layup of resin at the scrim and when the heat of cure happens and the cells outgass into resin starved inner layup and you will have poor bond! Also if the resin is mixed hot for the first "paint of the scrim" the heat and shrink will warp the panel. The best way is to mix a cool batch and paint one side, let sit tell barely tacky and then flip the panel and rest it on something like scraps of starboard or poly so it wont stick and paint the other side.

[44'cruisingcat]

I've met Ian, ( builder of Lyra) he's a fairly good friend of Bob Oram. He certainly doesn't claim the material is perfect. The panels didn't bend into as fair curves as he would have liked, and he can't get as much forestay tension as he'd like - the hulls flex.

Anyway, it's your money, and your choice. It wouldn't be mine.

Good luck.

[beiland]

Don't get me wrong here, I'm not trying to be combative.....just want to learn both sides of a story.

In your experience you site above do you think your problem might have been some resin starvation (wicked away) as has been suggested?

Originally Posted by 44'cruisingcat

I've met Ian, ( builder of Lyra) he's a fairly good friend of Bob Oram. He certainly doesn't claim the material is perfect. The panels didn't bend into as fair curves as he would have liked

I can believe that. I need to look over his website, building record again to see what I might discover anew. I also wonder about fairing out the final glass additions one might add onto the prefabed panels.

and he can't get as much forestay tension as he'd like - the hulls flex.

Most catamarans have this problem with headstay tension, and its due to hull flex and rigging down the center of the vessel. That's exacerbated by his mast aft arrangement. So I'm not surprised by this, and won't put all the blame on the construction material.

With proper sandwich skins I do not think the polycore should be any worst for flex that if the core was foam or balsa.

[44'cruisingcat]

These are commercially made, pre-glassed panels. The glass appears to be wetted out properly, but I can't comment on whether there was enough resin used for the scrim.

The core is 15mm, the glass 400gsm. Compared to 13mm Balsa cored Duflex with 400gsm glass, it is very easy to bend.

Again, I suggest you get some samples. Make sure they are big enough to get hold of though - around 300mm x 100mm, say. You won't learn much from a 100mm square.

[beiland]

BTW, sir,
did you finish up that very nice job you were doing on your vessel?

I saw a very nice 48-50 Schionning's cat that he had been built up in Thailand. He used the Duflex panels, but the foam panels, not the balsa ones. I have some photos somewhere.

[44'cruisingcat]

Yes, approaching 18,000 miles now.

[beiland]

Originally Posted by colemj

Nidacore has much lower shear strength than balsa and foam. Our boat is made of Nidacore.

Mark

Hi Mark,
I'm reviewing some postings here and....
I'm wondering how you came to this conclusion...specifically?

Did you experience this with your boat....or did you get it from a spec sheet?

[beiland]

Originally Posted by Esprit Marine

Olliric,

The following differences can be highlighted between a catamaran built from a DuFlex kit, and one built with a traditional male or female tooling method :

- the DuFlex panels are laminated under hot press. Although the same pressure benefits (high lamination strength, low resin content) can be achieved in situ with vacuum infusion construction, the heat curing allows to double the strength of the fiber-epoxy. This is equivalent to boats built in pre-preg and oven cured, a process generally reserved to racing boats.

- The 'Z-joint' assembly between the DuFlex panels, has a strength which is from tests up to 20% less than that of the board. This is taken into account by ATL composites for the scantlings calculations.

- The Duflex kits for the CE Spirited catamarans, are totally different than for the Australian Spirited. The Duflex panels thicknesses and laminates have been calculated for each panel with regards to exposure to wave and CE category, in accordance with CEN ISO 12215-5.

Hi Olliric,
These Duflex panels you refer to, are they balsa or foam cored?

I do understand these 'panels' are built under 'controlled conditions' to obtain "high lamination strength, low resin content".

Is there any reason that PP cored panels can not be produced in this same 'controlled' manner. Are not the 'basic panels' from Polycore produced with the first skins under controlled vacuum molded conditions?

Then the subsequent builder adds onto these basic skins. That builder may also elect to build subsequent skin layers under controlled conditions.....as did the Solitary Island catamaran guys.

[beiland]

Originally Posted by 44'cruisingcat

I looked into aluminium a little. One thing I found is that it's much harder to finish the interior of an aluminium boat. A Duflex or glass boat can be painted inside, which keeps it light. With alloy you have to build frames to support a liner, which all needs to be removable to access the hull. It all adds weight, as well as being extra work.

I mention that on this other subject thread...oops haven't posted it on this forum's discussion, but its coming soon.

http://www.cruisersforum.com/forums/...es-106073.html

[colemj]

Originally Posted by beiland

Hi Mark,
I'm reviewing some postings here and....
I'm wondering how you came to this conclusion...specifically?

Did you experience this with your boat....or did you get it from a spec sheet?

No, our boat has no problems at all with its Nidacore build. My comments were from spec sheet technical data. I see no reason not to trust these to be correct data.

Mark