Builders with Ethics?

I agree will all of this and your previous post too.
In my yard we fix lots of problems with cored boats. Personally I would not want another cored boat. (except for maybe the deck). Balsa rots, foam comes apart. All the "advantages" go away with time. We have worked on one fully cored long rage trawler that is so rotten in the core that picking it up with the hoist is like trying to pick up a rotten tomato with with a toothpick. Built for long offshore trips? I don't think so. I wouldn't trust it on a rough day on the lake. And you can't really fix it. It's now junk.

Speed, stiffness etc. etc.- I don't believe this construction would be so popular unless it was significantly cheaper than solid glass. Todays' boats seem to be designed and built for the magazine "boat tests" lol, and the sales brochure. From what I see many many pleasure boats spend 90% of their time sitting at the dock and really don't get run very hard or very often. The boat builders have probably seen this too. Their job is to survive and sell boats. Their market research probably tells them that granite countertops and goofy looking curved hardtops sell more boats then a seaworthy hull does. So, they can build 'em cheaper and sell more. In a way you can't blame them. Ok maybe you can.

Ah - I was confused with the build date of Certifiable then - Certifiable was 2008 and Absolutely 2005?

As for divinycell - it appears still to be mainly air and soft plastic - in the video (and on other boats) you can see it's clearly parted company from the GRP far more extensively than the GRP has with other GRP laminates, and you can see this in a number of damaged cored sides too - the little blocks sitting there uselessly as the two thin GRP plates flap about independently. One can only wonder at the use of this construction in a curved section that holds up the deck and superstructure.

I suspect if used in a honeycomb format (particularly with balsa) it would be quite strong, but the huge expanses of GRP loosely attached to the other skin by a bunch of partially attached foam blocks gives me cause for pause - from an engineering viewpoint I can hardly believe they do that, and would not have believed it if not for the pictures I've seen before (of other boats - not the Bertram).

I friend of mine bought a old cored speed boat once too, we lightened it considerably by digging out a huge mass of saturated smelly plastic sludge that the foam had become - this boat had been out of the water for a while too. Since then I've never been a great fan, and will never buy a boat with core anywhere in the hull, including grid liner interiors. I want to lift a hatch and see the woven pattern, and tap it with a hammer to hear a solid ring. Perhaps I'm in the minority here though . I've seen the odd rotten deck too where the builder has screwed straight through into the core, but I can accept a cored deck if they've used balsa and been careful.

geriksen: I always find it ironic that a high mounted granite worktop sits in a boat that's built 'light' to go 'fast', I have a lump of granite as a shelf and home and it weighs a ton!!

I suppose the ethics have been based on a 'never going to use it hard' basis of quality but when the boat gets stressed and falls apart it discourages new buyers and boaters - and of course costs the company in warranty work too. Then when a salesman says 'it's a great investment' people never believe another word he says. Every manufacture who builds boats like this damages himself and the industry in my view - it's very short sighted.

If I was in charge of government I'd mandate a minimum certification scheme (like a house) where the planning and building were subject to checks so just like building control stops you building a window without a lintel it would stop builders riveting decks on etc. The EC/EU nearly has this in a 'small craft directive' but I wouldn't trust the EU as far as I could throw them - so it would probably have to be set by lloyds or insurers. In fact insurers could introduce a certification scheme and offer highly discounted rates for boats that complied - if there was a will to organise. It would certainly make sense!

On boats the granite is usually skin thin and glued on a light core....

Yes that makes rather more sense..
... especially given the cost!

Removing the flybridge would shave weight off a few boats TBH