Boats to Foam or Bottles ?

Mombakkie
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Re: Boats to Foam or Bottles ?

Post by Mombakkie » Thu Dec 05, 2013 1:01 pm

Another interesting comparison would be the difference in permeability of uncut foam vs cut foam. What I mean by 'uncut" is foam that is poared and then left as is. When the foam sets it forms its own "sealed layer", as soon as you cut or shape it you break this layer. My thinking (common sense) is that "uncut" foam is far less permeable than cut foam, have no evidence of this which is why it would be interesting to do a simple test to verify whether this is so or not. Don't have any foam though :|
So in my opinion it would be better to first glass over the bouyancy space to close it and then cut a hole via which to pour the foam. Often one has to tilt the hull to get the mixture to run and not sit in one place so it fills the space completely. Excess foam is allowed to escape via the hole to eliminate deformation of the hull or stringer system.
Once set the only cut will be where the hole is which is then glassed over as well, so a much smaller area via which water can penertrate the foam.

Anyone who's worked with foam will have a better understanding of what I'm trying to explain.
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BFC
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Re: Boats to Foam or Bottles ?

Post by BFC » Thu Dec 05, 2013 3:11 pm

Mombakkie wrote:Another interesting comparison would be the difference in permeability of uncut foam vs cut foam. What I mean by 'uncut" is foam that is poared and then left as is. When the foam sets it forms its own "sealed layer", as soon as you cut or shape it you break this layer. My thinking (common sense) is that "uncut" foam is far less permeable than cut foam, have no evidence of this which is why it would be interesting to do a simple test to verify whether this is so or not. Don't have any foam though :|
So in my opinion it would be better to first glass over the bouyancy space to close it and then cut a hole via which to pour the foam. Often one has to tilt the hull to get the mixture to run and not sit in one place so it fills the space completely. Excess foam is allowed to escape via the hole to eliminate deformation of the hull or stringer system.
Once set the only cut will be where the hole is which is then glassed over as well, so a much smaller area via which water can penertrate the foam.

Anyone who's worked with foam will have a better understanding of what I'm trying to explain.
The trick is to have the foam detach and not tear from what it attached itself to during the application process, and the only way is to treat the surfaces correctly to achieve that and then there is no issues with foam or bottles for that matter and either or. The problem is when not done right to fix a kak foam job and the various complications it gives later on in the lifespan of that hull. Some buttcats of the pre kamassi era had a newspaper buffer between the glass and foam and seemed to work well , or well enough until fuel came into the mix.- that's is just nasty.

this is what it looks like when buoyancy foam and fuel mix - not that the two should ever mix but if a boat is built that it does then it looks like this.
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thika
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Re: Boats to Foam or Bottles ?

Post by thika » Thu Dec 05, 2013 3:13 pm

On this topic:

This matter of one third of the flotation at the back is going to become an issue if enforced

A way to go would be to foam your fish holds (if they are towards the back)

Or foam some above deck storage boxes on your catamarans :)

On my boat I would gain 500kg of buoyancy at the back, but would then have to somehow carry ice and fish above decks i :(

@ Miles,

before you loose your marbles, the new approved bottles are hexagon and they pack tightly together and are durable

Something else, I have 270l of fuel below decks...this should not even count towards the deadweight carried by the hull as it is lighter than water, thereby favouring the buoyancy calculation

Most water on boats leak through the deck when washed or from standing uncovered outside, not through the hull

I still believe the best the best floation you can use in your boat is a 6-man liferaft !

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willem wikkel spies
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Re: Boats to Foam or Bottles ?

Post by willem wikkel spies » Thu Dec 05, 2013 8:01 pm

my deck was vrot, moes alles uithaal en deck oordoen.
die bottels in was melk bottels, plastiek een lieter tiepe.
hulle was duidelik baie oud.
hulle almal het daai aluminium strokie oor gehad wat hulle aanvanklik mee geseel was.

so met die jare se see ryery, skud die goed teen mekaar.
van die bottels het deur geskuur aan die kante ae ander aan die aluminium strokie.
hulle was niks werd nie.

so voor ons foam kon insit, moes ek die hull seel, maar moes eers die ou vessel glas skuur met die grinder, regte k*k job, want alles is vol veselglas stof en alles juik.
hulle het gese een laag vessel glas. ek besluit, bogger die, een laag is te min as jy in ag neem, ek het skoon geskuur.

so toe gooi ek twee lae vessel glas.

Nigel boat het net foam gegooi en geseel met een lag.

hoekom als een lag moet wees, weet ek nie.

ek gooi toe self nog n lag oor.

my center console is nie met skroewe vas nie, niks is met skroewe vas nie, alles gefiber glass.

so daai romp is behoorlik geseel.

ekt seker gemaak daarvan

sal n kiekie moet plaas

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willem wikkel spies
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Re: Boats to Foam or Bottles ?

Post by willem wikkel spies » Thu Dec 05, 2013 8:04 pm

die deck
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willem wikkel spies
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Re: Boats to Foam or Bottles ?

Post by willem wikkel spies » Thu Dec 05, 2013 8:07 pm

skuim in, dis seker due enigste tyd wanner skuim op aarde goed is, in jou boot se hull
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willem wikkel spies
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Re: Boats to Foam or Bottles ?

Post by willem wikkel spies » Thu Dec 05, 2013 8:09 pm

hull geseel bo
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willem wikkel spies
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Re: Boats to Foam or Bottles ?

Post by willem wikkel spies » Thu Dec 05, 2013 8:11 pm

n onder lag en dan center console uitgemerk, verf af
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willem wikkel spies
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Re: Boats to Foam or Bottles ?

Post by willem wikkel spies » Thu Dec 05, 2013 8:14 pm

ok console is op'
jy boor nie n gat in my hull nie!!!
klaar jy het geen rede nie
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willem wikkel spies
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Re: Boats to Foam or Bottles ?

Post by willem wikkel spies » Thu Dec 05, 2013 8:27 pm

ok self waar die transducer sit, boor jy nie gate nie.

wat jy doen "my voorstel" is jy skuur die gelcoat die size van jou houtjie.

jou houtjie verf jy heeltemal met resin, skoon resin, geen vessel in nie.
hy kry n mooi gladde afwerking.

die kant wat jy teen die boot wil plak moet onder wees.
wanner jou houtjie droog is, maak jy die onderkant grof met skuur papier.

op jou transom, merk af met masking tape, maak seker dat jy die onderste gedeelte ook afskerm want resin gaan afloop en jy kry dit nie van die gelcoat af nie.

nou n blokkie vessel of twee so groot soos jou blokkie.
smeer met resin en plak.

om te keer dat jy altyd daar staan, masking tape die blokkie hout vas.

resin sal set en hy sal vas wees.
nou boor jy skroef gaatjies in die blokkie hout.
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