Spray on fairing material?

[nevilleh]

I dont know, this is was what the class society surveyor wanted , it was to change direction every 2 layers so we didnt argue !

My biggest issue with building these is the fact that we need to stand on the mat to lay up the inside. I dont like that but its common practise I suppose.

Our new 35' mould is 12' wide so that will be the same, ideally we would have made a split mould but our class society surveyor wanted quite a rigorous joining method so we just made a single piece mould.

Cheers

Originally Posted by nevilleh

I dont know, this is was what the class society surveyor wanted , it was to change direction every 2 layers so we didnt argue !
Cheers

Though not completely uncommon, this is not the right way for a layup on the outer skin!

You should start a the bow. In this case the overlap is in the right direction to avoid delam when the gelcoat gets destroyed while the boat runs at speed.

You are aware of the "Bertram" delam issue, where exactly your layup pattern caused further damage?

The first time I agree with one of our "chopper gun professional´s" comments. He must have found a good book.

Regards
Richard

[nevilleh]

This is actually the 4th layer going on, the one below goes parallel, and the one below that accross.

We actually use a rather expensive wax free resin so as to stop delamination.
We changed to that this year after conducting tests in to delamination & overcoating times that I was paranoid about.

The larger companies sometimes dont have much control over their quality as the guys on the floor dont really know whats what.

I have seen some vessels where by you could quite easily peel a layer completely off !

[tunnels]

Originally Posted by apex1

Though not completely uncommon, this is not the right way for a layup on the outer skin!

You should start a the bow. In this case the overlap is in the right direction to avoid delam when the gelcoat gets destroyed while the boat runs at speed.

You are aware of the "Bertram" delam issue, where exactly your layup pattern caused further damage?

The first time I agree with one of our "chopper gun professional´s" comments. He must have found a good book.YOU FORGET I CANT READ!! REMEMBER !

Regards
Richard

To carry that theme on a little more same when you gun ,you start at the bow and gun across and work towards the stern .
And yes for hi speed craft of any size this applies , be it 12 foot of 60 foot .

[Landlubber]

....emmm...looks like first lay anyhow tunnlels, they will obviously be using biax later anyhow??????? (fingers crossed eh)

[tunnels]

The layers of glass form a fish scale effect its the lap that helps protect each of the layers if you hit a object while underway , The faster you travel the harder the impact . If glass it lapped the wrong way it is much easier to shed the layers of glass and for the force of the water to get between and simply delaminate the whole of that layer from Bow to stern in one foul swoop .Lapping the layers of glass for every layer is a preventative measure to slow of stop the rest of the layers from coming off as the force of the water tries to hydraulic between the layers .
During the 1960,70,80s lots a jet boats were glass but the pounding and hitting rocks at speed put short paid to glass hulls so them the questions of why are they coming apart lead to the ways of construction , lapping of layers , types of glass used and making complete boat hull in one swoop so was wet on wet layers , different types of resins until finally there was a switch to Aluminium hulls . Layer the methods used were carried on to this day by people that understand how to build glass hulls .

[nevilleh]

Tunnels, As I have previously pointed out this is the 4th layer that you have seen. The first ones going along with the hull. We have proved our construction techniques with destructive testing for delamination as we got a fright when we found out about a failure of a local boat. Its incredibly easy to actually pull apart the laminate with a hand chisel on the vast majority of boats out there. We dont use biax in any of our construction , only CSM & woven roving.

[Landlubber]

"We dont use biax in any of our construction , only CSM & woven roving."

....sad.....

[nevilleh]

Landlubber, As I said earlier all of our construction is surveyed with Lloyds and DNV rules. On our older models we are required to stick to the original design which was made before biax got common. Our 26' boats have a combination of wr & csm to a total of approx 22 Oz. We could have equal strength for lesser weight but as these are workboats we still have an ideal all up weight which helps for seakeeping etc of approx 5 tonnes. To use biax to save a bit of weight in this situation is not required.

On our new model we have been told that it will be csm & wr again, which I am questioning because weight may then become a factor as it is 9' longer . One of our issues in the UK is that our main fishing boat survey people dont really recognise biax so it has kept some aspects in the dark ages !

[tunnels]

Woven And Csm Takes A Lot Of Beating !!
Has Been Round Since The World Was Flat .
Never Mind All You Fancy Stuff !!:d

[Landlubber]

....yeah, tunnels, good idea eh, forget that biax has the strength in the right directions, has better impact resistance, faster to layup, etc etc......just bury your head in csm and wr........

...mate, i am all for strong boats, changing the layup specs can make the boats far stronger in all circumstances...

[Landlubber]

...biax being fancy stuff.....are you for real.....

Originally Posted by Landlubber

...biax being fancy stuff.....are you for real.....

He never was!
You know he is a chopper gunner, so what did you expect, knowledge?

[Herman]

I just infused a 9 meter rib, which, given the design requirements (a freaking amount of stiffness and strength required, and very low weight, and Lloyds approved) was only possible in biax (+/-45 and 0/90). I managed to save another 20 kgs over what we anticipated (based on test laminates that I made, and keeping in mind some bridging, which always occurs). Customer was happy. He will infuse the 2nd one next week.

For Lloyds approved multiaxials, contact Formax (Oliver Wesseley) in the UK.