glassdave

iTrader: (1)

gotcha, actually i went through some of the pics again and your right there was to much left intact for my theory. for some reason i was thinking the rear of the main cabin was blown out to. Man this is a puzzler. Well I'm out of ideas . . . .we're they anywhere near the Bermuda Triangle?



Great thread though, lot of good info being tossed back an forth


INCONTHEVIABLE! . . . .lol . . . The transoms not blown out . . . its only mostly blown out . . . .(as Miracle Max would say) (great movie)

Steve 1

Uncle I always use Sheet core so until the patterns get 100% it is"Fun" cutting a boat inside a boat exactly!! Now in production runs the suppliers will "Kit" the core-set for you in boxes the way you use it IE First piece on top.

Steve 1

Uncle I Apologize for not bringing this up sooner.


Here is a simple graph of what Nauti was referring to.

http://www.fram.nl/faq/how/SP_CoreCell_comp.pdf

Uncle Dave

Thanks! Lots to digest (again)

Interesting.

Page 4 has good data, lots of it relevant.

Some data points are of questionable relevance to our discussion.

This shows an interesting set of trade offs.

UD

Uncle Dave

Sounds like work - cubed.

UD

MidOcean

iTrader: (2)

http://www.yachtforums.com/video.php?title=sunkbertram

nautdesign1

Uncle dave- Your friend Steve1 is spot on. Balsa is more tolerant of less than optimal bedding practices than the foams. This is one of the reasons (price being the primary one) that balsa is so popular. Just don’t let it get wet…

spk1

http://www.bertram31.com/articles/tgiabertram.htm

this is before ferretti took ownership, back then both bertram and hatteras were battleships, I have seen both hit jetti rocks at 20-25 knots and be fully intact resting on the rocks. One was a 50 bertram 1990's model, that hit the rocks and sat fully intact, untill the tide came up and sank it, and the other a late 70's 53 hatteras hit the jetties in galveston, and powered its way to the yacht basin where it was lifted out. They definently do not make them like that anymore, hatteras nor bertram, Viking is still putting out a battleship, and a few of the custom guys build a hell of a boat, but in my opinion some of the larger corporate builders just arent getting it done.

Uncle Dave

What forums do you frequent that I can I go to , to get more info from?

I'm guessing by the use of the word "whilst" twice in one mail - you are British (I work with a bunch of Brits love those guys) Im in the TV/Film business - you?

Im absorbing the provided data, and would like to continue asking questions - but wish to do it in another thread so the bertram info doesnt become more contaminated with "core discussion."

I dont think with proper vac-bagging there is much danger of the balsa getting wet, yes any through hulls need to be treated very carefully.

Can you adress any possible other downsides foam MAY have?

Im curious to hear more fine details that adress T2x's comment (as Ive heard the same thing myself,) and would love to get some closure on it i/e flexing of the core material that leads to shrinkage (of more than ones wallett)

In line with you reminding us that F=ma if you could construct 2 boats , one of each material that weighed identically your explanation seems to imply that its simple issue of light always wins- (definitely preferable) and proper bonding technique combined with lightness lets them "Get away with it." - What else is at play here?

It seems like everything else, core choice is a series of tradeoffs you wich to build under rather than one is always right and one is always wrong.

Much like the Epoxy VS VE discussion- there are tradeoffs. Some VERY vehemently argued by some, and denied or downplayed by others.

I find many shops that build both foam and balsa boats still use balsa as much as foam- Im eager to learn more.

Can we start a new thread for this discussion? I said early on I was open to data and you guys have provided some good reading, but I need more......


UD

spk1

Im not disagreeing with you on the transom blow out cause, but some of the larger sportfish do have an engine room access door, just under the stairs that lead down to the galley, the water would probably blow through that door and into the engine room and back before making its way up and through the salon, I didnt really pay attention to the access points on that 630, some didnt have the door, but I still believe even with out the door, water at a heavy force would break through the engine room bulk head,before heading up the stairs, most of it is just heavy insulation for sound, and not necessarily heavy water proof construction.