<<It is necessary to get the core properties in all directions.  Even better would be to include the tow at +/-45 to fore and aft.  >>

  You'd probably want it in at least four/eight directions (major compass points), at 45 degree angles to the skin for each one.

  There are some places where there's pure tension, and vertical tow would help, but shear stresses are more likely to be a cause of failure or delamination, and those will change in direction depending upon what's stressing the skin and where in the structure the skin is. 

  If a bow hits a big wave, or lands on some sand, both skins on the bottom of the hull will be in tension, trying to keep the bow from bending up.  But the core in the bottom will have shear in one direction, while the core in the sides will have shear in another.  Then at the top of the hull the structure is in both compression and shear.

  It would be interesting to see a cost guesstimate of the tow cost, plus labor for drilling the holes and laying the tow, in comparison with a standard build with a more expensive core.

        - Mike

 

On Mon, Dec 3, 2018 at 1:00 AM '.' eruttan@yahoo.com [harryproa] <harryproa@yahoogroups.com.au> wrote:

 

| > Rob; it would seem tow through the holes would adds a lot to skin to skin adhesion, right? To the point that foam skin interface might not matter at all/do not need to worry about it?
| >
| If the skin laminate was thick enough not to leak, which would be at least 2 x 600 gsm, which is the base laminate for a C60.

Ah, so your feeling it is water under the laminate that is the issue, not the physical adhesion of the two? Or am I misunderstanding?

Adhesion would be fine, the hull skin would not, unless the skin was thick enough.  

| And the tow was at 45 degrees to the skins in both directions. So, probably not.

Why would the two need to be in both axis to have better skin adhesion?

No.  It is necessary to get the core properties in all directions.  Even better would be to include the tow at +/-45 to fore and aft.