[PCW] Nida-core, ground effect

[brian eiland]

But it doesn't work too well with vacuum systems (infusion, etc), does it
Pat?

And there are some problems with 'print thru', particularly with
polyester resins and its honeycomb structure??

Brian

------ Original Message ------
Received: Wed, 04 Mar 2009 07:58:15 AM EST
From: "Pat Reischmann" <preischmann at msn.com>
To: "power-catamaran" <power-catamaran at lists.samurai.com>
Subject: [PCW] Nida-core, ground effect

  I would not be concerned about Nida-core I have built over one
  hundred boats
  out of it. Though not as strong in shear as some foam cores, it does
  not fail
  catastrophically like cross linked foams, since the polypropylene
  honeycomb
  will deform or bend first, it has great peel strength because the
  thermally
  fused polyester scrim creates a good physical bond to laminates,
  acoustically
  it is vastly superior to other cores, and it costs less. It will make
  for a
  heavier laminate than some foam cores, since the scrim absorbs some
  resin, and
  it is not as stiff in shear compared to some foam cores, so laminates
  would
  need to be thicker for a given panel strength. It is unaffected by
  water, and
  I have seen water drained out of the core in some cases without
  affecting the
  laminate. The first seventy five Manta's were built entirely, hull,
  deck, and
  bulkheads out of Nida-core and polyester resin, and they are all
  going strong.
  IF price was not an object and/or I was building a race boat I would
  maybe
  look to other cores and epoxy resins.

  On the subject of ground affect or air cushion I would be hesitant to
  say
  emphatically that no benefit is gained under 25 knots. It has been my
  experience that it can help at lower speeds than that.
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