Aquasport Model Rebuilds, Mods, Updates and Refreshes > Fiberglass and Materials Corner

Theorical Physics.

(1/3) > >>

Seadog:
I've got a sort of physics/hydrodynamics question I'd like to ask about water for all you scientifically minded guys.

I found standing water in foam filled stringers, in a 1970 Aquasport 222.  I mean a lot of water!  The stringers were made out of glass only.  Looked like a layer of mat, then roven, then another layer of mat.  

These stringers did not have any signs of holes being drilled into them, and no signs of any structural breach in the construction.

So if that is true - if the stingers were intact with no holes and no breach in integrity-  then my question is: how did the water get in there?

I don't really have a solution to this question, but I have some ideas.  

Whatcha think?

Jerry-rigged:
My guess - The fiberglass let it thru.  As I understand it, all Ester-based resins are water permeable.  Poly-ester more than vynelester.  Of the common resins, I think only Epoxy is not water permeable.  Epoxy is more expensive, though, so boat builders don't use it.  Do a search on the http://www.boatplans-online.com message board (link on the top right of their home page).  There have been several discussion there about the different resins.

Jerry

Wilson:
I think that jerry hit it.  You have to have lots of water sitting close to it for a LONG time for that to happen.  But just look at gelcoat and what causes gelcoat blisters.

JimCt:
Seadog,

  I agree, all glass boats will take up a fair amount of water (make that weight) if left in.  Small boat racers (sail, maybe power too) haul out when not racing to keep them light.  The soaked stringer problem could also be related to the foam used.  A proper spec. closed cell foam (which may not have existed back in the early AS days) will stay dry inside.

Question I've got:  Why were the stringers completely closed up with no drain provision in the first place?

Seadog:
I thought it interesting that fiberglass laminates are not as non-porous as once thought.  That water can 'seep' thru the glass given enough time, and that water intrusion is not always due to holes drilled.  So the water I found in my boats stringers was probably partly due to condensation that will vary with temperature, barometric pressure and humidity, but a lot of it was seepage thru the glass that accumulated over 34 years.

Jerry-rigged - thanks for the link, that's a good read. I've read that the fiberglass strands, the basic manufactured glass, has not changed much at all over the years.  But there has been huge advances in the packageing of the glass - Double Bias ect, and huge advances  in resin  and foam technology.

Wilson - are gel-coat blisters caused by water intrusion into the tiny air pockets left in the gel-coat?  That would mnake sense.

Jim - That's exactly the question I asked when I found all the water in the stringers.  Why the hell didn't they afford for water drainage out of the stringers?  But then if they would have left in drains, water could have also drained in.  It was probably a design flaw.  Don't know if later Aquasport models were designed any diffferent.

So what does this have to do with re-buildsand everyday use of our boats?  Probably nothing...

Navigation

[0] Message Index

[#] Next page