Knitted fabrics. 45/45 vs 0/90 vs 45/45/0

2 layers of Uni directionals at 45, 45 to centerline with a layer of uni running for and aft.

This is a 0/45/45 triaxle
Its proper use is gelcoat +300csm resin rich with Vinylester and left to harden over night then the triaxle and what ever else is in the laminate stack . !!

that chunk pictured, of coremat and csm peeled directly off the balsa core of the boat in the yard hit by the roller scaffold.


The cormatt is used as a print blocker for the Balsa !!
This is absolutely crazy !!! core matt should never be used in this way at all .
Core matt is a material used to reduce the amount of resin in a given thickness of a glass layer !! its just a glass material with q cells impregnated into it !!
Example if you wanted a panel 6 mm thick thats stiff ,then 2 mm solid glass ,4mm core matt ,and 2mm of solid glass .
Originally corematt came from the building industry for flat panels or panels the has shape that most foam or balsa cores could not be laid and were solid heavy glass .
The strands of glass are continuous and brittle so its breaks very easy . A word of warning its not any good to use in panels where theres movment and vibration . eventuallu it will shear and simply come apart .
The next worse thing lots people do is starve it of resin if it dosent get th e right amount of rsin to completely saturate it its going to fall apart . its impossible to over wet cormatt !

A and B boats if one glossy and 100% smooth and not a sign of glass any where beware !! and ask for the layup !! if they dont give it to you they have something to hide so dont touch it !!.

 

Here is a really basic lay up tell me what you think of it !!

Gelcoat
300 gram csm
450 csm +0/45/45
1350 csm
300csm 45/45/90 +300 csm

Its using triaxle but could us double bias in place of triaxle !!

This laminate concept is simple and can be added to as the size of boat increases just by adding to the amount of csm that there as a core or using heavyer weight triaxles or double bias . This a good basic everyday layup easy to do easy to lay and not a lot to thinkabout .

 

So bak to original question... If you were going to spec the lamination schedule for a 25 foot boat (Surfhunter type hull performance requirements) where do you start?

Hull sides -
Gel coat
1.5 CSM .75 oz at a time allowing to harden between layers.
2 layers of 90/+-45 (90 running gunnel to chine)

Gelcoat
300 gram csm left to go hard
450csm to bed 45/45/90 (Look at it !!)
300 csm +good time to use a 3mm core matt
300 csm +45/45/90 inside


Hull bottom
Gel coat
Same CSM
1 layer of 0/+-45
strakes treatment from above
2 layers of 0/+-45


Gelcoat
300 csm left to go hard

Time to build you strakes
as alread stated

450 CSM +45/45/0
1350 CSM
300CSM TO BED 45/45/90
plus internal framing and stringers etc etc

this would be my choice for the 18 footer even up to 50 mph in almost any sea


How much is too much? ask a naval achitech
How much is too little?

Thickness has not much to do with the ultimate strength and depends what strength you looking for . Durability is me i want a layup that will last, its what i look for !!


I started thinking about this when reading the Fairy Hunt 18 mold restoration and build thinking that the layup was very light in that boat. I know that hull and it can take some pretty big water for its' size and I would have thought there should have been more glass in there.


Its not so much the amount of glass but the quality of the glass used

(beautiful work... Just questioning layup schedule.)

Cheers!

Ian

 

Are you talking about 45/45/90 with mat or without?
If without why? As a layman, I would think it better to only have to cut 1X not double for each 'unit' ( mat / bi or tri).

1350 grams of CSM? What is advantage of this vs mote structural fabric? Cost, ease of application or something else?

Cheers!

Ian.

 

Are you talking about 45/45/90 with mat or without? The weight of csm attached is a sprinkling its your choice with or without
If without why? Its just another choice you have to make !!sometime you can buy and sometimes you cant
As a layman, I would think it better to only have to cut 1X not double for each 'unit' ( mat / bi or tri).

1350 grams of CSM? What is advantage of this vs mote structural fabric? Cost, ease of application or something else? solid csm makes a really good core and if you talking about pounding and hitting things its pretty damn good !!
If you worried about time involved cutting glass ,pull all the layers required in there true sequance for both sides of the boat and use a electric cutter and cut it all at the same time then roll each of the layers in the right order for each side and place them on eachside of the mould so you dont have to think about it any more !! :?:
Cheers!

 

Got it.

I assume at keel, all of this is doubled because of overlap and chine is close to double. Eca use of hull side to bottom overlaps.

You prefer coremat to foam for making hull sides stiff? Thinking thin corecell or equilivant.

Again, thanks for dialogue and experience.

Ian.

 

Ok actual construction methods
Keel is very important , and also the transom and if you happen to over lap layers any where in the first and second layers of glass .
Keel and overlats go from 15mm up the transom all the way to the sharp end and very point of the bow !!! what way do you over lat the first layers of glass always start at the front and work to the back the overlaps are back overlapped onto the front layers !! why ?? well its known as fish scaling in the case of a collision and a object pearcing the skin it had a tendancy to deflect away and not tear into the layers . just like fish scales runa knife ofer a fish from h=nose to tail its really hard to penetrate the scales to the skin but the other direction you tear straight under the scales so the same thing with glass layers . i worked with clever guys over the year this is something new ho ho ho we been doing it for more that 30years plus .
Overlaping side layers in the keep 200mm total 100 up one side and 100 up the other !! all layers are done the same if you have core materials leave a 200 mm wide strip full length and the core covering layers ened up glass to glass up the middle . if one side gets punchered the water pressure cant get from one side to the other Now all clear what i have just written ??
Chine
The bottom layers come up to the chine and round the corner and atleast 50 to 8- mms up the tops sided . the topside layers come down to the chine and round onto the bottom glass the same 50 to 80 mm so you end up with a overlap of 100 to 160mm if the bottom gets holed the water should not be able to get past the chine into the topsides . so step the bottom core back 80mm away from the chine both sides so the covering glass can protect the topside glass and core from water pressure penetration or soakage . chines are the place that get hit and knocked and a hard time so solid glass is easer to repair and will take much more punishment than a thin skin of glass over a soft core and the glass will damage easly .
The transom glass comes down onto the bottom but only 30 to 50 mm down onto and around . if a sharp object slides along the bottom to the transom its more likely not to rip off the transom outer skin .

All these principles have been used and good builders all over do the same thing !,its possible to simply look at the way a boat has been glassed and instantly tell if really exsperianced workers have made the boat and its good or not so good !!. .

Theres lots more as well but this is for starters !

 

Oh and I just surfed the Internet for an hour, googling Laminate schedule and googling well known production boats. Zero information on how they are laid up. Only goofy things like " rugged " last a lifetime, indestructible and CARBON FIBER !!!!!!!!


Is " Laminate Schedule " the correct term ? and why is this laminate description such a closly gaurded secret ?

 

Every one has there own ways of using glass and usually no one is prepared to shove there head in a noose and speculate . Then you will hear the laminate has to be engineered by a composites nerd sitting at a computer punching buttons and spitting out pages of magic laminate scheduals .
But the computer will only advise you what to use by the information it has been feed . computers only sort information and if you dont ask the right questions you wont get the answer you looking for or want to hear .
There are books in library's that can help you with a basic layup for what ever sort of boats you building But glass has changed since the book was printed and the info is only a basic guide or starting point .
Most companies i worked dont have any thing written its just information handed down the ranks and if you happen to be standing at the very end its follow the leader . if you ask what is the laminant you will be sitting alone at lunch time and no one will want to talk to you !!. they look at you and ask what do you want to know for ??
Most companies that use chopper guns the gun operater regulates the amount of glass that he feels should go on the mould . if hes having a bad day then it could be a bit light here and there and if hes away and some one else takes over then you get his interpritaion of what it should be .
For the guys i work with i measure and spec what each part of the hull should have for each laminate !!,
i made a work sheet with discriptions and weights of glass and amount of resin used and the theoretical weight and the actual weight used . It takes all the guess work away and if adhered to 99% then there is no guessing .Each work sheet stays with the hull till its finished and the signed so some one is answerable for the quality of work done !!. That scares a few people to be made accountable for there actions . all the work i have done for longtime has been to survey standards so i have devised the same standards to protect the company i work for and the workers that did the job !!:?:

 

From the consumers viewpoint...Why cant I have information on the laminate schedule of a boat ? An overall description of the boats laminates, resin used, molding technique.

A wooden boat would say ...oak frames, cedar planking, bronze fasteners....

This is what causes me to think of all composite work as Dark Science.

And Im a boat guy with much experience with hundreds of boats. What about Joe the Plumber ?

 

yes it was made in China and you cant match our service

Long time ago we used to get an owner come and stand and watch how his boat was moulded . i always thought it was a good idea .
like i just posted the china company here i already made a good start with a job sheet and all the build instructions and who the head person was for each part of the bulid ,this sheet stayes with the hull till it was finished then the deck the same and so on all way to the finished boat is launched .
All collected together this would give a complete work history of the making of everything it is a stage better than getting a survey . It was done as a way for the company to be able to hand a copy of this information to the new owner and a record of its very beginning and record of all the materials used . its better than a survey quality without the enormous fees . Do you know of any company that does such a service ?? not even any of the survey companies do such a service !!

 

Sounds good to me. Hopefully this is standard operating procedure with quality boats.

What about the secondhand market ?

Both boats fit your budget. which one was laid with a chopper gun , which one has long fibers.

Which one is stiff, which one is soft and floppy.

On a small boat you could just climb around the bilge and gain insight. On a bigger boat with a shell interior lining the laminate is invisible.

 

What about the secondhand market ?using the recorded history all the information is recorded so it stays with the boat and the new owner has it given to him .

Both boats fit your budget. which one was laid with a chopper gun !
what is wrong with using a chopper gun??, which one has long fibers.Long strands ???

Which one is stiff, which one is soft and floppy.
the record system would be heaven for such occassions

On a small boat you could just climb around the bilge and gain insight. On a bigger boat with a shell interior lining the laminate is invisible

 

There's allways a need for one more thru hull, or renew a old one to bigger diameter (to see what the hull is made off)

 

On the little race boat I was involved with all fibers were long, shear to shear, bow to stern... all uni directionals set in epoxy over foam. We were just kids so no vacuum, just hand consolidation room cure . If I remember correctly the structural outside skin and inside skin were the same laminate schedule.

45 45 and triaxial was not available at the time . It was a tough little boat and still lives today, so 35 years old.

Original info given the owner lasts a few years then gets lost. That info should be avaible on the website of the boat manufacturer or stamped into the ships documents. . So that when I researching 15 year old boats, I can immediatly judge its build qaulity before I spend time inspecting it.