Catastrophic delamination on a new Bertram

That laminate looks dry. There are voids.
And the windows! The guy on the other forum said they were put in with silicone...there HAS to be more than silicone, right? There are glues that can be used, urethane maybe. Richard, you can safely install glass with urethane as long as there is physical support, can't you? They do it in cars.

[Fanie]

No matter what type of 'core' you use, the strength of any boat lies in what it is wrapped in. Few materials are as strong and durable as fiberglss and if designed and applied correctly there is very little chance of failure.

I always say you cannot build a boat piece by piece and expect parts not to delaminate. Sooner or later a knock or bump is going to start that part delaminating. At least the last outside layer should be one solid piece.

If I look at the 'methods' some builders use to save their own costs (and this doesn't apply to them all) it makes one feel a bit ill. The hull is the one thing you don't want to scrounge on.

I'll sh2t myself if a hull delaminates. Look at me lips... ONE PIECE in ONE GO !

[Fanie]

Originally Posted by Commuter Boats

The whole concept of utilizing cores is not faring very well amongst most of the posters. As I see it, the problem with this Bertram is with engineering and quality control. I operate a repair shop and do some low-volume construction in cored composite, my largest built to date is 40 feet and fully cored. I guess I just don't like seeing cored construction get a black eye it doesn't deserve.
Gerald

Gerald, there is nothing wrong with cored materials in boats, in fact they do have a significant role to play.

The problem with most materials is that they are not really suitable for construction unless properly supported by something else ie fiberglass. The aeroplane guys also does that, supporting their honeycombs with fiberglass, the more so should it apply to boats. A hull takes a hell of a bashing in the water. Just try hanging in front of one while underway

[tunnels]

APEX1 from Hamberg you need to Back you a little !!
Theres a lot of really good boats that have cores and as the price of fuel keeps going up world wide so we have to look at the ways of making boats lighter and strong and cores play a vital part in this process as do new and better fabrics to go with the cores , plus lighter more powerful motors and so the list goes on and on !!.
Some of the blame can be put on the core but 80% is down to the workmanship and 20% the engineer that specified that particular product . He may sit at a desk and be a wizz at pushng buttons and coming up with all kinds of colored graphs and getting totally confussed in his own little world of bull dust , But has he ever had his hand stuck in gloves and spent hours breathing styrene or done the hard yards and know first hand about the products an d material hes spec'ed to replaced from the original that has never been a problem since who know when ?
Theres a general rule of thumb that people should take notice of , Foams at not good to use in hull bottoms ! Top sides ok but not bottoms .
Look at this and remeber it 80% of failures are caused by bad workmanship and the other 20 % is bad choice of material's

Cored hulls are crap!

[Alik]

Originally Posted by apex1

They have procuced the next catastrophe:

http://www.yachtforums.com/forums/ge...iscussion.html

That was a reputable builder a few decades ago. Then they started to make "cored" hulls.

Greed? Impertinence? Shareholder value? What drives such a company to risk their customers lives?

I hope the market will "honour" it this time. And people will learn that cored hulls are cr@p.

But boating press keep brainwashing the consumers on 'advanced high-tech builds'. Every builder that claims to be not 'high-hech' but simple and reliable is at risk of getting out of business. The result is on photos You posted...

Originally Posted by mark775

Richard, you can safely install glass with urethane as long as there is physical support, can't you? They do it in cars.

Yes of course.

Originally Posted by Alik

But boating press keep brainwashing the consumers on 'advanced high-tech builds'. Every builder that claims to be not 'high-hech' but simple and reliable is at risk of getting out of business. The result is on photos You posted...

Too true, and too sad.

But there is still a clientele not buying all the "high tech" claims. Good for us.

Regards
Richard

[tunnels]

There is nothing hi tech about building boats ,nothing at all . I have been building Glass boats since i started work in 1972 and very little has changed if anything we have gone backwards in the past 20 years , dosent matter if its power or sail ,big or small there is nothing high tech!! .
You want to see suffisticated laminants and laminating proceeder's get into the industrial glassing industry then you will have got some where , boating No way!! .
Most companies havent graduated past woven roving and chopped strand matt !and some of then still dont know the differance between E matt and P matt
Wake you people! take you blinkers off and get off the sofa put down the tv remote and stop mumbling!!!! .

[Alik]

Originally Posted by tunnels

There is nothing hi tech about building boats ,nothing at all

I know this. In reality, very often high-tech claim is just a reason to charge more and build slower with unknown result. I just published this conclusion here.

As to me, my boat is all in sandwich (bottom also), but designed and built properly. OK, it is stored on trailer, not on water...

[TeddyDiver]

Originally Posted by tunnels

spent hours breathing styrene ; bad choice of material's

Other thing wrong, not crap maybe but piss instead.. nothing to do in cored structures..

Originally Posted by tunnels

APEX1 from Hamberg you need to Back you a little !!

Theres a general rule of thumb that people should take notice of , Foams at not good to use in hull bottoms ! Top sides ok but not bottoms .

Have you seen the video I linked and refered to? NO

But you should........

.....before you make dangerous statements.


Foam cored hulls are crap!

[Fanie]

If you use the core material as structure, then forget it, you will keep on running into problems.

The core is suppose to add stiffness (after the hull is structurally sound) as an inner layer, also heat insulation, sound and flotation.

Not structure. I know it is used as a former in some cases, but again the foam has no strength and does not contribute to the strength of the part at all.

[tunnels]

Originally Posted by apex1

Have you seen the video I linked and refered to? NO

But you should........

.....before you make dangerous statements.


Foam cored hulls are crap!

I would like to see the video you are refering to ! can you put up the video address again please .
Tell me how glass boats should be built ! what would you use and how would you use it for the hull construction of a 36 ft power boat that should do 25 to 35 knots and what kind of hp would you recommend to get the boat to that speed ! Single motor or twins ?

[tunnels]

Originally Posted by Fanie

No matter what type of 'core' you use, the strength of any boat lies in what it is wrapped in. Few materials are as strong and durable as fiberglss and if designed and applied correctly there is very little chance of failure.

I always say you cannot build a boat piece by piece and expect parts not to delaminate. Sooner or later a knock or bump is going to start that part delaminating. At least the last outside layer should be one solid piece.

If I look at the 'methods' some builders use to save their own costs (and this doesn't apply to them all) it makes one feel a bit ill. The hull is the one thing you don't want to scrounge on.

I'll sh2t myself if a hull delaminates. Look at me lips... ONE PIECE in ONE GO !

B]No matter what type of 'core' you use, the strength of any boat lies in what it is wrapped in.[/b]
You need to really think about what you have written here !! so if you have a strong skin inside and out it dosent matter what the core is !! are you really sure about that ??? so if the glass on each side of the core comes loose and the core crumbles it dosent matter ! is that what you are saying ? its what i am reading !!
One question = do you build boats for a living ??

[Alik]

Originally Posted by Fanie

If you use the core material as structure, then forget it, you will keep on running into problems.

The core is suppose to add stiffness (after the hull is structurally sound) as an inner layer, also heat insulation, sound and flotation.

Not structure. I know it is used as a former in some cases, but again the foam has no strength and does not contribute to the strength of the part at all.

Wrong statement. Core is part of structure and it works for SHEAR, while skins work for TENSION and COMPRESSION.