Catastrophic delamination on a new Bertram 63'...

I was told that HMY gave him a 68 to use, after two weeks he returned it.

I've heard that his 63' replaced a prior 63' that had major issues. What makes you think the quality on the 70' would be any better then the two free replacements he already had?

Really? I know he had a 57 but didn't know that he had another 63.

yeah actually it was a 57, and it was oil-canning. The stringers were all seperating on it and I heard they gave him the 63' to replace it......and we know how that came out.

O ye of little faith

While the older boats were built with plywood bulkheads & stringers and otherwise conventional methods that had been used for years, this new 700 sports Corecell PVC vacuum-bagged bulkheads and heavy-duty structural foam stringers capped with unidirectional E-glass (the stringers that support the engines are nine inches wide with one inch thick steel plates embedded within; the motors are bolted down with hardened steel bolts), plus Knytex and honeycomb partition bulkheads. The keel is formed of structural foam and encapsulated by 30 laminates of various high-tech fabrics. Borrowed from the Ferretti offshore powerboat racing technology is the use of hull ribs: these square-in-cross section athwartship scantlings traverse the hull sides down to the keel. Overkill? At over 38 knots at the wave-dance, maybe not.

----excerpt from the YF review of the Bertram 70

The athwartships hull ribs and engine stringer thickness are impressive by any measure. In fact, it ought'a be called the Scantlings Room instead of the Engine Room. I don't know if the 57 (or even the 63) was constructed like this 70, but short of a chemical bond failure, I cannot imagine such a robust structure coming apart.
My $.02

Isn't a chemical bond failure the reason his 63' came apart? That is what several people have told me was the cause.

Trailer Boat Technology... ... for a SF????

com·pe·tent
Pronunciation:
\ˈkäm-pə-tənt\
Function:
adjective
Etymology:
Middle English, suitable, from Anglo-French & Latin; Anglo-French, from Latin competent-, competens, from present participle of competere
Date:
15th century

1: proper or rightly pertinent

2: having requisite or adequate ability or qualities : fit <a competent teacher> <a competent piece of work>

And your point is.....?

I guess it somehow makes sense to him, because it sure as heck doesn't make any sense to me!

So it's not just me!

Hi,

This is in his Public Profile.

Occupation:
DOE in Composites Industry and retired BNN Member

I don't know what a DOE in Composites Industry is but guess this is why he says that there is some incompetence in the use of what he feels is Trailerboat Technology on a Sportfish Boat.

Exactly.

Guys,

SandEngXP is DOE ( Director Of Engineering ) for a composites company. Good to have more qualified people joining our discussion.

for starters trim tabs too small

I seen it all worked at RBI service yard over 20 years, fixed factory f-ups for lots of models in lots of years, the f-ups are getting to the point they are un-fixable, had a conversation with a bertram engineer a few years back he said they wanted to shave 10,000 pound off the 63, I told him that with the new high HP engines coming out and the lighter materials being used they are going to start breaking bulkheads or worse, they went past that point of "or worse" while back

I was somewhat surprised that a composite engineer would suggest that the description of the scantlings for the Bertram 70 is 'trailer boat technology' when foam/alloy grid filled stringers/ribs/bulkheads are used so very effectively in the most trying environments. Airliners/military aircraft/race cars for example. Consider also the parameters for the lay up design of Ermis II as a 115' motor yacht doing 60 knots spec'd to withstand 2.2gs of acceleration forces (way in excess of all registry standards apparently). Obviously the cost is something else in each of those extreme examples but prudent use of composites is a matter of appropriate engineering design and build integrity suited to purpose surely? With these high speed large SF designs either you seemingly have to use cored composites to achieve a sensible weight or should they now be built in aluminium for a similar result at perhaps a more tolerable cost?

Nobody wants an Aluminum sportfish due to the noise they put out while fishing and maintanence.

If speed and strength are sought in a sportfish, Cold molded is still the way to go and I haven't heard of any of those coming apart.

Builders need to keep in mind that when you start mixing all sorts of different composites together that they all flex at different rates and actually try to come apart where they are joined together because one section is stiffer then the other section and that section moves slightly. Such as the stringers and bulkheads if the coring is a different manufacture and stiffness.

Also when using composites and such in Formula 1 cars, all of the parts are bolted together and not fused together like a boat. This gives them some room for harmonics and expansion rates and different flexing when they deal with a lot of G forces

Yes, I see what you mean about cold moulded boats and that perhaps was the first application of what we now seem to call composite construction. Remains in common enough use for custom builds here and no doubt in the States and elsewhere. With the use of multidirectional layers of resin saturated ply or wood strips (such as cedar) as the core that is then encapsulated in an FRP skin, this combination has a lot of strength and is still relatively light. That method of building hulls has been around since WWII and is well tried and tested but it is still a matter of prudent design whatever composite method is used in my view. High end aluminium yachts are as quiet as mice - at a cost!

Not sure at all that any bolts are used in the assembly of a F1 carbon fibre tub (chassis) - certainly the engine/transmission section incorporating rear suspension etc and front suspension mounts are affixed mechanically plus further fairing and the fiddly bits but the guts of the car is a pure FRP fused lay up as I understand it. Perhaps the ironic point here is that they use bolts to attach things, not just for assembly/maintenance, but also for when it is designed to break unlike the FRP 'tub' itself!

if you build it like a gofast its will fall apart like a gofast

You can not think its strange in an off shore race when a driver that knows what he's doing has a boat fall apart around him. So if you take the same stuff and build a 10tun or more boat you can expect the same result. The boat will go fast but may fall apart if put it under the right amount of stress... Now if you take in to account the hours of use & the the weight of a go fast & power boat you just may find, the weak end power boater may be more likely to have a hole open up on there hull.. After all the stress of a 10 tun or larger boat crashing into and thro a 4 foot or bigger wave can be much grater on the 1 inch core hull then that of the boat that sank at last weeks, last months or last years race. I know what your thinking "that little race boat was going 2 times as fast as me" and your right but on top of the wave not thro them & o ya it was only 3000 pounds or so.. And with weight you have to take in to account hull flex meaning the way a cored hull bends when between waves or cresting. Now your hull is not on a travel lift resting on the two arias marked sling line where the weight of your boat is built to rest out of the water, so lets say 10 tuns of your 15 tun boat is hanging center on a big wave the wave dose not care if its on your sling line it roles right between the bulk heads and the hull will need to support the weight of the boat at some point. If it cant it will bend. if your hull can not take the stress it will fail.

For years air craft bodies have been alum and honey comb composit and now the new super jumbos are 100% nomex. But air crafts are regulated by the FAA and boats are regulated by hype and wallet size. An aircraft has less over all stress on its cored parts to date seeing as only the new super air bus is 100% nomex, and the full life time service service plain including xray to check out how its doing, this is all FAA mandated... But aircraft still dose have its history there was that plain that lost large parts of the cabin over the ocean,,, and the plain that crashed in the ocean leaving NY right after 9/11 it lost its the tail due to stress. There if a butt load of info the FAA forces to be public record, tests that have to be cared out on any composits going on a plain. I saw some where a crack in a cored skin travels at like a 1000ft a second or some thing, so its not like the b52's of old that limped home full of holes, now you here one loud pop and up drop to the ground or ocean floor...


You'd think some some one be building a solid glass hull by now....
Fallowing the stuff that worked years, years ago and use all the fancy composit junk in a cool way. To build a lasting boat that can run over logs or rocks or get beached and have no real hull damage...



Love to see a hull built with a sheet of by-axle kevlar then by-axle carbon, fallowed by 1 inch of s-glass on the bottom and a 1/4 on the sides and a top layer of by axle carbon just to make it a solid glass CORE kevlar carbon sand witch hull. Then put in some nice composit nida core carbon bulk heads and decks, nila board stringers. Just build it like bertram did and use all the good stuff like 100% epoxy, no wood or gellcoat. Then some big hi rpm diesels, she'd be slower then the go fast fisher men's but at least 1/2 the speed and she'd be SAFE in a storm or up on a reef & most of all she will not sink .

lets face it going fast is cool but sinking will make a dork out of the coolest customer...

just a thought...

You might want to spend a bit more time researching aircraft construction. The new Airbus 380 (if that is the one you are referring to) is about 25 percent composite by weight and it isn't made of Nomex.

The FAA is not the certifying agency for Airbus. The French might have a few problems with that idea.

You definitely want to do some more research on the failure mode of aircraft composites. There are no components where "one loud pop" or single point failure will cause a catastrophic failure as you claim.

Hi,

In addition to the above I would suggest that some basic naval architecture would also probaby help you with any future boat design or construction/re construction plans you may have.