Catastrophic delamination on a new Bertram 63'...

my post was more about core hulled boats I have no need to prove core hulls suck as the photos are all over the web. Seeing as your stuck on the smaller part of my post maybe the larger part was correct....

I stock and sell nomex so there are 50 sheets sitting in the next room, I have done a little reading on the stuff and can keep up with the guys at dupont when we chat..

So the FAA dose not look at plans built over seas if the plain is sold and operated & serviced in the good old usa. wow that is a scary loop hole... they send little french men here right, or may be that is why bowing is going,,, So that is just wrong. The FAA is involved with any plain operated by a US carrier and it service history.

Plain builders, started using nomex for decking and over head storage then the plain bodies now wings, tabs and so on.... not going to split hair on the % of composits used in aircraft it gets larger by the day...

One point will not cause the crash but leads to the next failure that at some point results in crashing.

Rapid decompression typically takes a little more than 0.1 to 0.5 seconds and pop.

that latest plain that crashed didn't it brake up in flight when the speed sensor iced up? pop or pop, pop, pop at the end it still drops.


in close the aircraft guys use composits on a much higher level, you were never sold a ticket on the way a pain is built. the plain was built the way it is for reasons. boats are built that way they are for ego, lighter faster better. and so go fast & you may sink just as fast...

Your right fallowing the exact build as my 35 bertram only using carbon, kevlar, s-glass & epoxy with cored bulk heads. that is out there right?

I never try to reinvent any project I have finished or am working on I only follow the builders model..

and if its a 73 bertram you cant go wrong.........

Scantlings v. Technology - Not the same thing.

I have not signed on for a while and thought this thread had died.

Let me offer a few clarifications and observations:

Trailer Boat Technology would be the low end of the composite materials and process spectrum. Slightly lower would be sheet molding compound. At the upper end, fighter jet and space craft 'technology'. All these are different points in the spectrum of composite technology but they are not even close to equivalent. A quality SF design lies somewhere to the middle of this spectrum and is rarely appreciated how sophisticated it really is.

I would challenge those who do not like Sandwich construction to this observation - the reason we can all sit around and second guess the merits of sandwich vs. solid construction is because the sandwich boat most always makes it home. There is rarely evidence to critique of a solid laminate boat as it is on the bottom and rarely recovered. I have personal experience in the former and corrective design experience with the later.

On the subject of aluminum, designs with it can be made quite light compared to trailer boat technology and heavy compared to fighter jet technology. Aluminum, however, in my experience makes poor high speed craft (boats). There are many examples of HS aluminum craft that need regular re-welding after a run... (and they are noisy and cold)

F1 primary structure chassis is aluminum honeycomb with carbon epoxy prepreg skins made in an autoclave. This would last a few months submerged in salt water and generates its own electricity from the galvanic reaction.

Sandwich Construction is a very efficient way when properly designed and manufactured to produce many high performance marine structures.

I think your 100% correct..
"Sandwich Construction is a very efficient way when properly designed and manufactured"
most boat builders use the most un skilled workers for the lay up the ones willing to get dirty. and the lack of any regulating keeps manufacturing at the lowest cost.


I know there are lots of cored boats slowly soaking up the sea under them that will float years and years, get pulled out dried and re soaked for years and years. its not about sinking...

here is my thinking
its about a stupid simple lay up that that manufacturers can manage, a system that is strong will out last 3 owners and ride out any storm, that is big if you live in south Florida and your boat may end up humping a dock in a 200mph wind for five hours as my boat did. No cored boat will live thro that , its like putting all the weight of you boat on the pilings your tied to and you'll have holes. A low piling becomes a 10tun pound punch in a storm, just as soon as the storm water lifts you above it, but a 1/4 inch glass hull will crack the gell coat scrach you boat but that is about it. So there's a lot of photos of bertrams beached and bashed but not a lot of old bertrams pre 80's with holes in them ..

cores have there place on larger manufactured non off-shore style boats in the deck, floors, bulk heads & interior. and if some of the neat cores out there start braking down in years to come like the dash in an old car or get brittle like the plastic kick panels of a 70 nova I may end up wrong about that also. only time will tell


they pulled an older striker out across from me to restore an aluminum hull boat rot holes you can put you fist thro, also seen my share of steel tugs and barges, & like wood is worm food aluminum and steel is not the best hull material in the sea.

as far as larger boats built today, that live life floating nothing stands up over time like solid glass. there is a 200 year old steel boat in the water down from me & an old cold mold that gets varnish every 6 months, so I am talking manufacture 30 x 13" foot and up non go fast boats.

I live in miami and has been a BIG fan of bertrams for decades .. !!!!
but new bertrams are a big P.O.S.

There are many new users HIGHLY dissapointed with them and some are terror stories. Many complains and many unsatisfied clients.

Since ferreti took over, apearance and fancy-stuff-looking seems to be the priority for the yard , not seaworthiness.

They forget these are battlewagons, not kayaks.

what a disgrace ....

eloy, miami

Steel is actually your best material to build a boat in when it comes to strength. That is why most tug boats, ships, and war ships are made of it. It also will last centuries if properly maintained. Electrolysis is a major issue and has to be constantly monitored. Also, it's easy to make a one off boat out of either steel or aluminum and they both have their place. The beauty of both is that if you have a thin section, you can just weld another plate on. Neither steel nor aluminum will take neglect and sit around without any zinc anodes for years with no issues to the hull like a fiberglass boat will. Also all it takes to have an issue is to lose a wrench or tool in the bilge.

The issue I see with cored boats is that the outer skin of the fiberglass is relatively thin. Once that is punctured and you start getting water intrusion into the coring, it really really weakens the composite and very quickly. Solid glass in my opinion will take a lot more abuse before it is punctured or the seaworthiness is sacrificed. Cored boats may save a little weight, but as other people have said, they are built with very unskilled labor with various quality control. I have also noticed of all the cored boats I have run, as they age, they have slowed down and slowed down as time went on. It seems impossible to keep them from getting heavier and heavier. One un-bedded screw hole for a bilge pump or float switch or anything that sits in a wet bilge and water will slowly make it's way into the coring. I've run both and much prefer an all glass hull.

Some interesting comments

"This fascinating conclusion contradicts some present-day thinking, which holds that solid carbon fiber bottoms are best. High Modulus did their homework under the supervision of Germanischer Lloyd surveyors, and impact tests revealed interesting results. “While there was more visual damage to the thin-skinned cored panels than to the solid panels, the damage deep within the solid panels—completely invisible to the eye or to tap-testing or to other mechanical impedance methods—was catastrophic...This provided a graphic illustration of the superiority of appropriately cored sandwich laminates over their solid laminate counterparts in serious impact loadings,” Downs-Honey said"

This was said in an interview about the scantling design and build of Ermis II, perhaps an extreme example of quality composite building. Perhaps you have to factor in boat building skills as a prerequisite but there is no excuse for any 'name' builder to be less than 100% in terms of build-quality integrity for high speed sea going hulls. Many of the 'name' builders and naval architects seem to now contract these specialist composite outfits (like High Modulus owned by Downs-Honey) to undertake their lay-up design but they may well cringe mightly if the builders fail to follow the rules they need to apply for the productionh lay-up. The comments quoted above reinforce what has been said in this threat by other qualified experts in composites. A lot of solid glass builds are crap and there is no lack of sorry evidence to claim that.

Sorry about the clumsy typos - Friday night here and I was having a beer!

Where was the tests conducted, in London? They sell there name to products that they approve most made in England, There a little funny there at Lloyd. See there is a lot more to do with it then just one sever impact where a core fails its from flexing back and forth the sheer, there are 100's of posts on line showing just what happens to a cored boat in a bad storm with 200mph winds, It may just beach wrong and punch a hole or float over a piling, but more often then not its the endless pounding on a dock or see wall and the flexing that causes delamination then that slick carbon outer skin is weak and has no tension or compression and that is why a core is strong so it rips and well you got a new submarine. Just search storm survey, core survey or hurricane survey more then one report and Lloyd payed more than one clam, in the last 10 years for this reason.

The strongest thing on earth is water, it cut the grand canyon and well shaped our world if there is a way for it to find a fault it will,,,, there is nothing that is used to build boats that can get around water. So filling you hull with any voids when even an epoxy carbon skin suffers from osmosis under the weight of the boat over time it is just dumb sorry go's against all logic. never been one that dose not soak at some point that's a nice sponge you have there what year is it. Coolers are made better then most coared boats think about it right, more quality in an iglo cooler less parts nice clean mold no gell coat or paint to scratch, just need a new yanmar and she'll cook too. But is was more like that 24 pack in the cooler that made it seem like a good idea to build a 50 or 60ft cooler. Builder have the same excuse for bum work it is called the bottom line. and if your wallet and ego happens to exceed the size of you brain you to can have the fastest boat in the marina, to go to hell that is...


Just a little note if you cover solid glass on both sides with carbon do you know what you get? any one? is it, can it be, No not a sandwich core not a carbon fiber solid glass core that can't mean the same impact as the carbon core you refer to, same tension and compression system only no voids and well solid surface mechanical bond,,, this is the biggest point if you read a lot on cores. I know it hard but that is what my first post was about a hybrid using what has worked in the past and them fancy new things like carbon fiber....

by the way the photo is of a core from my 35 bertram hull ... the little black line is tri axil carbon that is right the good stuff most have never seen this stuff let alone worked with it... The green aria is where the core is on the newer boats if you feel safer with just 3 layers of carbon between you and you loved ones and the sea.. cool with me... you boat and life, but I'll keep my solid glass carbon bottom bert for life and tool around at 26k happy, and watch the new boats come and go....
and 36 years at sea is better then any thing you can find to prove your point on the web, See my boat was one of a lot of tests that made bertram who they are and allows them to steal money from the un knowing to day. I took her out of service she was navy owned and live her whole life with water under her feat 36 years and was tide to the dock thro any storm that passed port everglades... it will take 36 year to see if your right by then my bertram will be 72y/o and seeing as she had no damage so far I'll bet my hull looks better at twice the age of an 36y/o cooler.....

they pulled a 1956 steel craft tug out down from me a year with little to no zink and there were 200 or so small holes the power washer opened up, sad to think she made it that far just to go to junk over $500 or so in zink.... she was in need of a whole new bottom and now lives in the land fill.... nice lines on her I have a thing for tugs... thought about making here a twin hull by welding the holes welding in spacers and plating her, but up keep was what killed the idea. the photos are also of a boat I also had nice looking epoxy over wood I was building I sold for $600 just not right for the sea to much up keep,, to bad she was nice looking

There you go - you have been a composite boat builder - epoxy/glass over a wood core!

Ya I like solid composite core for a boat bottoms. epoxy over wood good for a lake not the ocean, stronger and lighter the soled glass but soft core is good for a race boat only, foam, nomex, nita, dvinacell and so on.. just not that good...
Just a side note on a second + to being solid. know why a bertram rides the way it dose? for the same reason a 4000lb full size car drives like you floating on a cloud. its heavy......

You can fight the over flow of endless data on bum cored hulls that gets added to daily by owners. Or read the data packaged for you by the boat builder they have no reason to lie.


you know why light weight is soled to boaters? Simple if you tell a buyer the cores cuts down on costs and build time, by getting rid of 90% of the resin and fiber in place with foam you can cut with a plastic knife. you know say what use to take 4 guys 2 day to cut and lay fabric, now takes 4 hours to lay in the dry fiber and set the bag on the mold and pull vacuum.

Put it like that and it seems like its just cheep, and it is....

Hi,

When you get the time to have a break from a few beers and your obvious self appreciation society promotions you might want to add Geography to the NA Skills I suggested earlier.

Germanisher Lloyd and Lloyds Register of Shipping are two completely separate and different organizations.

LROS is also not the same as Lloyds Insurance Co.

Germanisher Lloyd are amongst other things the worlds foremost composite classification society. They have by far the most skill and real life experience in the use of these "exotic" materials and methods.

Germanisher Lloyd as the name might suggest is head quartered in Germany, when looking at a world map laid out flat ( the earth really is flat you know) it is a bit to the right of England , behind Holland on the other side of the blue thing which is also known as the English Channel and North Sea.