This Week

This week will be tough on deadlines.
The dome acrylic project on the lunar lander dwelling came up two short. It seems the fabricators misunderstood the number 20.   The VHB tape is all ready in place on the dome.  The missing two panels must be installed as soon as possible.  I have a small weather window for tomorrow and wednesday there. Then Thursday is gone. I will be back in full next week.  This does keep me involved with all aspects of composite building, which benefits you the builders.


Fisheries Supply Comes Through

Not actual boat but boat construction.  On the lunar lander dwelling, my house built like a boat, I had planned to use the 3M VHB tape to stick the acrylic dome panels down.  I had understood that better results come from using an adhesive promoter in this cool time of year.  Uline, my tape supplier would only sell me large quanties of it.  I now now their minimum was enough to do about half a kilometer of tape.  Devon at 3M only had one idea of who in Seattle had some to sell, and they did not actually.  I had given up and went to Fish Expo.  At the Fisheries Supply booth there they had a 3M catalog.  Fisheries carries not the exact same AP111, but close enough, Tape Primer 94.  Fisheries comes through.


Surprising Stuff Done Wrong

This prime example of stuff done wrong was sitting right in front of me for a few days before I grasped the teachable moment in it.  And it is another example of what I have often seen where it is asserted “it must be right because they are famous.”  In today’s chapter, first the boat.  The bow broke off of this 50′ (I assume) trimaran in the Route de Rhum.  I have not seen the actual wreckage nor spoken to anyone who has.  But it seems like a lot can be understood by looking at these pictures.


Two things jump out immediately.  First, that sure looks like Kevlar, and second, the core looks thin.  It could be 19mm but it sure looks more like 12mm.  And the damage is quite clean, not ragged.

First, Kevlar?  Really?  In my opinion Kevlars’ only use is as a yuppie magnet.  Not only does it not actually stick to the resin matrix, but its compression strength is about 1/3 its tensile strength.  And it’s tensile strength is still 20% less than that of lowly E-glass. 

Now notice at the 3 corners of the hull section are tiny carbon fiber stacks.  That is bad practice on at least two counts.  First, the carbon has less than half the stretch to failure of Kevlar, so the carbon must fully fail before the Kevlar’s tepid strength is even at 50%.  Next, if it is a carbon stack as it looks, with the differing stretch, it could pop off the Kevlar with a shear failure. 

The clean break feels more like a tensile failure instead of buckling at first glance.  I see a scenario where there was a partial buckling failure which popped the resin matrix off of the Kevlar in a circumference line.  Later that weakened fabric is hit from the opposite direction and fails cleanly.

Why didn’t they know all this?  I can think of an elderly designer or two who would not know this kind of thing, but it has been out there for a long time.  Next, the Multi 50 rule is just as bad.


Fish Expo Time Again

Once again it is time for Pacific Marine Expo, (formerly known as Fish Expo) in Seattle.  Again, this is the serious boat show.  Or you could go to METS in Amsterdam.

 The show opens Wednesday, November 19th and continues through Friday, November 21st.Registration/Badge Pick Up is located on the concourse level. The Exhibit Hall entrance is located just down the stairs from the Registration area.
Registration/Badge Pick Up Hours:
Wednesday, November 19: 8:00 am – 4:30 pm
Thursday, November 20: 9:00 am – 4:30 pm
Friday, November 21: 9:00 am – 2:00 pm
Show Hours:
Wednesday, November 19: 10:00 am – 5:00 pm
Thursday, November 20: 10:00 am – 5:00 pm
Friday, November 21: 10:00 am – 3:00 pm
Planning Info:

Video of 37′ Tri

What a nice video, courtesy Jon Reed. I had not seen it before. It is Lance’s 37 tri that I designed back in ’86. Before CADD.  Still looks quite modern and fast to me. Cylinder mold plywood/epoxy.  Lance was professionally building Constant Camber but chose this for his own boat.  Still looks fast for a livaboard cruiser.  And it looks like somebody bought a drone doesn’t it?



Mystery Trimaran

I got a couple of pictures of what looks like one of my 37′ or even 40′ trimarans, from John who saw it. Located Block Island.

Does anyone know the boat? I first thought it was one of the 37s but it looks a bit bigger overall to me. If it is the 40, there is funny story. It seems that multihull legend Jim Brown went to look at it and its plans while it was being built.  His reported comment was “Hughes is just showing off.”



“the Making of Sumo” Picture Sequence

I had not before seen this sequence of pictures of the making of Pat LeMehaute’s KHSD 37 trimaran at Islamorada, FL.  The link is only on Face for now so you have to be from there to see it.  Foam/glass.  What an amazing job.

OK I find that none of the Facebook links work.  Will see what I can do to get the sequence here.  Kludge would be to go to Pat’s Face page and find the albumn.1931459_100834349939918_2630693_n