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Core foam or wood
https://hpbc.ca/viewtopic.php?f=19&t=3198
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Author:  MOTOboat [ December 26th, 2015, 10:06 pm ]
Post subject:  Core foam or wood

I've heard this from a few different sources.

Interesting

http://www.yachtsurvey.com/cored_hull_bottoms.htm



"People usually think that a balsa cored bottom would be far worse because of the wood's ability to absorb water. So far, the evidence at hand does not support that idea. Foam, because it is much softer, and not at all fibrous, breaks down much faster under hydraulic pressure. In fact, in all the test borings taken on this boat, the balsa itself was yet to break down. The actual failure occurred because the cored bottom panels were not properly terminated at the keel."

Author:  BoomerMuskoka [ December 26th, 2015, 10:25 pm ]
Post subject:  Re: Core foam or wood

this is why i chose to have balsa core put back into my procomp.. :D

Author:  phillnjack [ December 26th, 2015, 10:41 pm ]
Post subject:  Re: Core foam or wood

I would choose the balsa every time over the foam.
the foam is great if not squashed down or the skin of it broken.
but once that skin breaks its a sponge..

jmo

Author:  ATAZ [ December 26th, 2015, 11:39 pm ]
Post subject:  Re: Core foam or wood

I really like Nida-Core. The honey comb design maintains strength and flexibility. It doesn't break like foam under impact and because it's a polypropylene it wont rot if any water is obsorbed.

Author:  BoomerMuskoka [ December 27th, 2015, 10:00 am ]
Post subject:  Re: Core foam or wood

ATAZ wrote:
I really like Nida-Core. The honey comb design maintains strength and flexibility. It doesn't break like foam under impact and because it's a polypropylene it wont rot if any water is obsorbed.


nida -core still gets heavy when it gets wet, and for a pad of a hull you want it to be as rigid as possible to stop it from flexing under hydraulic pressure..

you gotta figure your 1550lbs hull motor and Driver!! are being lifted by a small part of the pad it needs to be STRONG and rigid.

Author:  idvette [ December 27th, 2015, 10:14 am ]
Post subject:  Re: Core foam or wood

People who tear apart a rotten boat seem to forget about the waterlogged foam they have to get through before they hit rotten wood, then blame the wood.... I still believe balsa is superior to any foam core material out there.

Author:  DoktorC [ December 27th, 2015, 2:21 pm ]
Post subject:  Re: Core foam or wood

RBT has been saying that for at least a decade. The is zero question in my mind as to what should be used in the running surface...balsa. And good quality plywood in the transom. Foam/composite core has its place...its just not in the bottom of a boat...

Author:  MOTOboat [ December 27th, 2015, 8:37 pm ]
Post subject:  Re: Core foam or wood

To me it's all about the layup. Yes I prefer balsa, but for really light short life span boats foam has its place.

Making sure you have the right layup schedule so the boat cures(chemical not mechanical) as a complete single sold with glass strands tuning the entire length of the boat it what makes them strong and last.

Eliminator, Allison and triad for sure I know understand the chemical process to make a boat.
The others, not sure maybe. When I ask the "nieve" questions I don't get the answers I'm looking for and that's worry some. They maybe just not willing to explain. I know Wally spent an hour discussing his layup schedule on my particular STV which made me feel a whole lot better about laying out top dollar for it and why I sold it for top dollar.

A lot of boat builders layup the boats and figure because it
Shiny and Cures were good.

I watched a very prominate F1 boat builder try and explain why a sponson peeled off in Russia after the third turn. It was embarrassing to listen to him.

Author:  DoktorC [ December 27th, 2015, 11:46 pm ]
Post subject:  Re: Core foam or wood

MOTOboat wrote:
To me it's all about the layup. Yes I prefer balsa, but for really light short life span boats foam has its place.

Making sure you have the right layup schedule so the boat cures(chemical not mechanical) as a complete single sold with glass strands tuning the entire length of the boat it what makes them strong and last.

Eliminator, Allison and triad for sure I know understand the chemical process to make a boat.
The others, not sure maybe. When I ask the "nieve" questions I don't get the answers I'm looking for and that's worry some. They maybe just not willing to explain. I know Wally spent an hour discussing his layup schedule on my particular STV which made me feel a whole lot better about laying out top dollar for it and why I sold it for top dollar.

A lot of boat builders layup the boats and figure because it
Shiny and Cures were good.

I watched a very prominate F1 boat builder try and explain why a sponson peeled off in Russia after the third turn. It was embarrassing to listen to him.


Light short lifespan boats...who cares...until you question "short lifespan" lol. But ya I get what you're saying. How much lighter is foam with equal strength? This has and will be debated forever I think.

Layup...well...this obviously has a huge effect on everything...balsa has a shitty reputation in our circles because of old hydrostreams. They all rot but not because the balsa is there it's because it's covered in chop and rigged by whoever. Put that next to an infused boat that's rigged by someone who knows not to screw the bilge pump through the inner skin and you've got a totally different animal. If foam breaks down under hydraulic pressure....basically beat to dust on the pad...how does layup help that, other than adding material to minimize the actual impact the foam sees? Basically adding weight in glass to save weight in core. Obviously, this won't be an issue for an ultra light raceboat that goes to chainsaw heaven after X number of laps...and I'm far from an expert when it comes to layup...but I did stay at a holiday inn express last night... :mrgreen:

Author:  MOTOboat [ December 28th, 2015, 9:39 am ]
Post subject:  Re: Core foam or wood

As a general rule of thumb, Foam and plastic composites do not absorb as much resin as Balsa, so it helps lighten the boat. Glass nowadays has such a variety for materials and offerings, so stiffness can be accomplished many times using this.

However my eliminator built, Kevlar, Balsa core, 20', 650lb Stoker made in 1983 it still bing pounded on Chesapeake bay by the guy who bought it from me, He's on the second motor and has to build a new trailer and done nothing to the boat... I should have never sold that.

So I think we're in total agreement :)

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