View Single Post
  #28  
Old March 27th 05, 02:35 AM
Dave
external usenet poster
 
Posts: n/a
Default


Unfortuntely, no.....

To often, it goes very deep, and has caused entire hulls to be
replaced or otherwise discarded...

Repairs are very expensive, usually requiring grinding out the
affected area, thorough drying, reinstalling the glass laminations and
resurfacing/finishing etc.

It can happen in salt, brackish and fresh water, and is worse where
there is a freeze/thaw cycle in areas that have freezing temps during
layup...

I have discovered it in vessels that have only been operated in
fresh water.

I see less of it now, manufacturing techniques/quality control has
generally improved. There was a bad stretch during the '70's
and'80's...

Other cases have been topside cracks that have allowed water to
penetrate into an unsaturated laminate (usually at a corner of a
structure) freeze and open the delamination further.This can also
become a structural issue..

Cheers!

Dave

On Thu, 24 Mar 2005 05:38:19 GMT, Don Tuite
wrote:

But isn;t that just gelcoat delam. Cosmetic, and it occurs by osmotic
pressure on parts of the hull submerged in salt water?





On Wed, 23 Mar 2005 23:07:09 -0400, Dave
wrote:

Ummm.............. I must respectively differ..

My company also does some marine surveying, ( inspecting
pleasure boats in insuring and pre-buy situations).

Ans , yes, I have seen many examples of this "delamination" of
composiets...

....many cause factors, osmosis being the most common, poor
quality control/contamination during layup are others....

Dave

On Wed, 23 Mar 2005 03:02:04 +0000 (UTC),
(Paul Tomblin) wrote:

In a previous article, "Montblack" said:
I read that composites don't show cracks, instead they have weak 'air
pocket' spots that can't be seen during inspections. These pockets of air
bubles(?) are caused by heat/cold to the composite structures over time.

My father, who was the Chief of Non-Metallic Materials at deHavilland
Canada said that this is bunk. Once the composite is made and given the
initial inspection, there is no way in hell they could delaminate like
that.