I got the paper pretty well updated and pushed into the digital medium.  Double click on the “wingmast17f ” below.

wingmast17f

Back in 1994 I had an idea that if you took the shear web out of a wing mast,  and added that material to the sides, you would have better section properties, and a stiffer wing mast,  with no increase in weight. And the panel aspect ratios would be closer to 1:1 so stronger actually.
In fact few alum masts have shear webs, but everybody forgets that.

First of all, I built two nearly identical wing masts; one with shear web and the other with the half of each shear web glued to each side .  Then I load tested them.  The improvement was remarkable.

Next I had Paul Steinert PE run a finite element study of the idea.  The results were so good that we wrote a technical paper together on it.  The paper was given and published at the 1994 MACM marine composites conference.

The paper had some difficulty later getting online however.  Word5 for DOS had a great equation writing feature.  The file would however completely  lock up any later  windows version of word.  Also, the images were slides of photos of the computer screen.  Those took some work to get digital.  Meanwhile I got busy and neglected that paper.  Recently I have realized that nobody has any idea what I am talking about without this paper being able to be online.  So, along with everthing else, I will get it into InDesign and make it available.

Meanwhile here are some of the graphics that will be in it.

I got to see three of my overloaded ferry cats there. I had no idea that they would put more than 200 people on them.
The next ones will be honest 85′ ones to carry the weight.  I just noticed that the shed behind makes it hard to discern the  outline.

January 16-18, 2017. Tampa, FL.
http://www.electricandhybridmarineworldexpo.com/

No cost if you sign up online in advance.

I’m not going this year, but it looks interesting.  I probably have a couple of cats there.

The big topic this year is battery safety.

On my recent trip to Belize I got to visit Tino’s boatyard. The mold is for a stretched version of my 65 powercat. the tables in the foreground are the flat bagging table. They do infusion there also.

 And does anyone have board molds and would like to build one or two for a 56′ cat?

OK, here are the pictures and hypothesis.   The owner reports that he didn’t hit anything and the crash block was not crashed.  Further, the balsa core was not soft nor rotted.  The laminate was triaxial, as was designed.  He thought there was a buckle on one side.

Notice that the balsa is at the faces, but there is foam in the middle.  It looks like Airex or divinycel.  Both in 100 kg density or less have much less shear and compression strength than balsa has.  Recall that the highest shear load in a beam is at the centroid, as is the lowest bending load.  Enough side load could move some of the rigid balsa into and crushing the much weaker foam.  The core is there for shear transfer between the faces.  Look how thin some of the foam layers look.  Crushed.   It looks like the weakest link failed, to me.

I got these pictures of two of my cats in Netherlands. One is the famous Zeevonk and the other is said to be a revised build of one of my designs.  Both wet and on the hard.   Anyone have any more information?

A very nice set of ongoing process pictures of Tom building his composite 36 cat in Netherlands.

A nice shot of Jim Dory’s vacuum bagged deck repair.

I leave for Belize in a few hours. Back next week. A couple of passenger ferries.
I will have the laptop workstation with me and I assume wifi.