foam-fiberglass cloth sandwich for hull

So your using styropore...EPS... Polystyrene foam...

What do you plan to build for real with these panels?

 

the foam which I may have for free is high density pvc foam
I tested panel -plywood/eps just to check how cross web can change the characteristics
when I have resin (waiting for) I will make epoxy/glass/pvc foam panels and let see how it works
I understand all pro and cons , also I understand why and what everybody try to tell me in all those posts. But I like the concept of truss construction.

It will be 15m cat, and we are talking about hull skin. If my concet doesn't work, probaly I go with plywood, but again I like if truss and ribs frame takes the load, and plywood will be mostly cover. Same as skin kayak from north.

 

I am building 11m cat with foam sandwich infusion process right now.

I know exactly how much resin you will use with PVC foam.

For 15m cat it is a big expensive project, you do not want to muck around. You will need at least 15mm panel thickness. This means with 3 layers of 5mm foam, you have extra 1200grams resin in the core per meter- so you double the weight of core compared to single piece of 15mm foam. So your core density is now 160kg/m3... More than end grain balsa wood... End grain balsa has much higher mechanical properties tho, higher shear compressive strengths. So you gained nothing except weight with this idea.

If you then try to make a truss in the core, you have to add even more weight... And you probably end up near the weight of western red cedar... Except you did half as much work with the WRC... 15m is a lot of work, are you sure you can handle so much extra work making your own truss core, just so you can have a very heavy 15m cat which won't perform well?

Don't mean disrespect, but your ideas don't make any sense and you are setting yourself up for disaster...

 

Obviously doesn't know how a truss works either.

 

In this size you must know what you do. Or you risk your own life, that of your crew and that of those who come to your rescue one day.

Obviously you don't know enough yet and therefore it is wise to ask questions.
From an earlier thread I saw that you intend to use Schionning plans.
What makes you unhappy with their building method and/or material choice?

 

unbelievable !!

what is it about cats that attract people that simply don't have any knowledge yet want to build a monstrosity 15 mtr cat !!
Its not a dinghy !!
Unbelievable !!!

 

How did you elevate yourself from no knowledge to become a boat builder tunnels? Did you learn composites mostly by watching other people at your jobs and copying them?

 

Am not a boat builder !!!but a fibreglass boat builder and that's the big difference !!
I learned by not standing watching but working with lots and lots of people for a long long time !! I learned by doing my own experiments when others couldn't give me answers because they to didn't know !! I worked doing boat repairs and doing modifications on boats that wouldn't go any good changing things and making boats go better . I learned and worked with really knowledgeable people all the time every place I worked , for the past few years I been working different countries showing young people and working with companies with problems of lack of up to date methods and knowledge of products and materials .

 

LMAO... funny sheet...

Tunnels has been around the traps for a while and knows quite a bit in that thick skull of his... the problem is, he thinks he knows EVERYTHING about ANYTHING to do with fibreglass! Like, whats the difference between God and Tunnels???

Answer : God doesnt think he is tunnels...

Its ok tunnels, my cat will be in the water soon, can you at least reserve judgement until then?

 

I like to thank everybody for help.
I'm closing this thread.
Best regards for everybody.

 

Tunnels, I think it's because large cats are more "house like" & comfortable, got a few "bedrooms" downstairs, coupla bathrooms too, lounge room in the middle often with a kitchen & a lovely back veranda with a great view...... so when Joe walks around with Joesephine & looks at boats at the show or where ever the cats & the cruisers get the heads up because they have elbow room & space & arn't cave like yacht interiors. Because cats are large with bulk square meters of structure etc. they have good price tags & not every Joe has that so they seek another way....................


& that's all I have 2 say about that.
From Jeff.

 

the situation can be more complicated when Joesephine doesn't want condo on water and Joe can't find what he wants
let cover this tread same way as they did with Charnobyl reactor.
In 2-3 years we know who was right, who was wrong
thank you everybody for respond

 

my point is boats are mans dreams and we all have them wet or otherwise . a 15 mtr boat is one serious piece of work . not only the expense of all the materials and equipment needed but the hours are unbelievable and finding an all weather place to build the monstrosity because that's really what they are monsters . the hours and hours that go into making the boat and if there's a family involved at the beginning they soon get bored and before you know it its becomes a solo effort and you really are alone . the dream very quickly can and does become a nightmare you cant get away from !! it takes over your life and the family forget who you are and friend look and don't call any more until launching day , trying to get family and friends interested most every times never works . then there's all the technical stuff , and everyone you talk to has or had a friend that did this and that and this worked better than that and in the end that or this has to work . You have to have dedication and knowledge , this is acquired along the way but you have to understand what will work best for what you are doing .
Groper is a self professed expert and I am sure one day out on the water all his short cuts and know how thinks is better than all us dummies will ever know will self destruct in a great shower of foam and shredded glass ! so if you want to join in his plight then good luck to you .
Nature always finds these kinds of people and there weaknesses and gives them the ride of there live out on the sea just before it bye bye birdy and screams for help .
I wiped him off my list and want nothing more to do with any of it any more !!!.

 

No he's not. He asks questions I'd like to learn about too. His bulkhead thread was informative until you started to ruin it with your "contributions."

 

Petethai;
A cored panel of foam and two skins absorbs load in the skins, one in compression, one in tension, this is where all the "work" is done.

The middle of the core is neutral, adding laminate to the middle only adds weight and a little extra thickness which in turn does add stiffness, however much more efficient to just use more foam.

As has been mentioned, bond the foam to get the thickness required then optimise the skins. Adding layers internally is wasteful and pointless.