foam cores and core materials

Discussion in 'Fiberglass and Composite Boat Building' started by Mark C. Schreiter, Jan 14, 2021.

  1. ondarvr
    Joined: Dec 2005
    Posts: 2,636
    Likes: 389, Points: 83, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    I didn’t go back and read Pascoe's stuff again, I read it years ago when it was fresh.

    In one paper he said he didn't really understand the properties of the materials used to build boats, and he’d never been in a manufacturing plant to understand the process either.

    Since he didn't know what he was looking at, he just came to conclusions that were a bit off in accuracy sometimes.

    This was back when I was in these plants every week and knew the build process for most manufacturers.

    There were products used in places that they weren't designed for, they were typically sort of adequate, but barely. In reality it was amazing some of the materials used held up as well as they did. The supplier/manufacturer of the product typically didn’t recomened the the products to be used in the way they were.

    One of these was the sprayable cores used at the time. These were marketed for cosmetics and stiffening of non structural components. They were used in hulls and other stressed locations, and poorly at that.

    Some of these hulls separated at the core, Pascoe reported this in a couple articles.

    A lot of these boats were built in the frenzy of manufacturing around the 80's. Many of the designs were good, but the production methods left a lot to be desired.

    People frequently discuss resin type as the cause of failure, it rarely is. You could use the best epoxy available, but with the skill and attention to detail that was available in production, they would have failed at the same rate as the cheapest polyester. The failures had nothing to do with the resin.

    Whether a core should or shouldn't be used depends on the intended purpose of the final product. The exact same materials could be great, or a total failure.
     
    Last edited: Jan 17, 2021
    Rumars likes this.
  2. Mr Efficiency
    Joined: Oct 2010
    Posts: 10,010
    Likes: 910, Points: 113, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    One aspect of cored boats of the planing variety, rarely mentioned, is that stiffness actually improves the ride of the boat in many cases, the bottom stays in shape with wave impacts, and doesn't develop "dynamic hook", which can increase vertical accelerations.
     
    TANSL likes this.
  3. wet feet
    Joined: Nov 2004
    Posts: 692
    Likes: 112, Points: 43, Legacy Rep: 124
    Location: East Anglia,England

    wet feet Senior Member

    One trapezing dinghy that I used to crew had the toestraps fixed to a bonded in pad at the aft end of the hull and it flexed a bit under load.My impression was that this aided performance a touch-getting the helmsman to sit out hard wasn't easy.......

    One thing that Daniel Savitsky's seminal work on panel loading showed was the importance of stiff bottom panels near the bow of planing hulls.Which also confers an advantage when a sailboat crashes down into a wave trough and the rigging doesn't go slack.Efficient sandwich panels are invaluable when properly manufactured and conform to the negative stereotype when corners are cut.The question is why those corners get cut-is it lack of training for the guys with buckets of resin or is it the beancounters dominating the discussion?
     

  4. Mark C. Schreiter
    Joined: Nov 2020
    Posts: 56
    Likes: 10, Points: 8
    Location: Tampa, Fl

    Mark C. Schreiter Junior Member

    I had no Idea he past away, probably wouldn't have started this had I realized.
     
    missinginaction likes this.
Loading...
Similar Threads
  1. Mark C. Schreiter
    Replies:
    12
    Views:
    1,391
  2. fallguy
    Replies:
    4
    Views:
    1,290
  3. keith66
    Replies:
    4
    Views:
    3,152
  4. tunnels
    Replies:
    34
    Views:
    5,007
  5. rwatson
    Replies:
    13
    Views:
    2,287
  6. Midday Gun
    Replies:
    10
    Views:
    197
  7. keith66
    Replies:
    14
    Views:
    460
  8. Iridian
    Replies:
    68
    Views:
    1,480
  9. Doran M. Oster
    Replies:
    27
    Views:
    798
  10. Prettypicturegirl
    Replies:
    14
    Views:
    485
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.