New Full Strength Latitude Here

The full issue of Latitude 38 is here. http://www.latitude38.com/index.lasso

In it I see that Bill Anderson is noted.

There is nothing like a newly painted boat. Starting in 1995, Bill Anderson, formerly of Squaw Valley, started what would turn out to be six years of hard work building his canary-yellow Hughes 36/38 Feet, the hulls of which are three layers of 1/8″ doorskins. He then sailed to Mexico, where he’s been living happily on about $500 a month. Having come into some money, he decided to have Sea Tek of La Cruz remove all the gear from the hull and deck and give the cat a shiny new paint job. He also got a new sled-mounted outboard and a power windlass.

Bill, send pictures!

Woodwind Lost

The other 55′ plywood/epoxy daycharter cat on Lake Tahoe recently went on the rocks and was ordered destroyed.
As a Searunner it had 1-1/4″ thick solid wood skin which always amazed me. The compression strength of the first layer is still the same. And with that much weight, the damage has to be more.

woodwindtahoe

Famous Laminates

Finally starting to get ahead of the deadlines a bit. Here is the hull laminate drawing by a very famous designer. I consider it completely wrong and I will explain. Every kind of forensic foray like this has teachable moments for all.
First, we surely all agree now that long, slender hulls are most loaded in bending or deflection, depending on the span.  Global loads,  like a wave at each end, govern over out of plane loads like, water pressure. I first learned about and began to design for global loads after the MACM ’86.  This drawing below is a decade later.

We also surely agree that to resist those loads, we must have the most and best laminate fibers oriented along the lines of stress.  Zero degree, along the length of the hull for these boats.  That is the best way to get a stiff hull.

This drawing has the vast majority of the glass laminate at +-45.  That is completely wrong to achieve a stiff hull.  It does have carbon on the inside of the hull, which does protect the fragile carbon  from crashes.  Typically I would complain about rule of mixtures, but the carbon is also +-45 degree orientation here.  The best feature of carbon, its very high modulus, is of no use in this arrangement.

And see how this is just as important for the hull deck.  For water pressure, the +-45 is fine, but again, the global loads are much greater.

One of the tests I used to do before I knew what to expect was to have my guys jack up one bow of a cat, and see that the other one does.  I remember hearing about Larry doing that on Sierra Cloud.  The other bow not only came up the same, but took all the blocking with it.

This famous cat deflected 3-1/2″ in the same test.  There is no reason to do laminates wrong.  Its not a mystery anymore.

shut52lam2

Boat Ronin

Ronin refers to the ancient saumarai warriors who had no fixed master.  These are boatbuilders who have a skill set and perhaps a shop but are not official boatyards.  Often they can travel to your jobsite.

Eric Friberg, in Bellingham, WA                         360-389-8599 and boatfriberg@yahoo.com

Ken Lincoln, in Port Townsend, WA          on Face at https://www.facebook.com/ken.lincoln.79?fref=ts

Joe Kitchell, west coast of north and central America.  jakitchell@hotmail.com and www.joekitchell.com.  He was recently featured in Proboat so he may have become a rock star by now.

Greg Feldman-  GF Marine             2741 Cranberry Hwy
Wareham, MA  02571      (508) 314-2706    gfmarine@juno.com

 

Anyone else belongs here, let me know and I will add.

 

Kevin On Powercat Helm Balance

I got these snippets from vastly experienced powercat driver Kevin to one of his sipmates.  Met one deadline and almost the other so I can do a bit here.
“Hope you’re not going to have to learn the hard lesson I learned about over balance. Remember how Holo helm was real heavy pulling out of a big high speed turn? We resolved it by removing most the balance. Regular steering improved too. Ran with only one rudder for a while too. Not much difference except at slow. This over balancing is also, I realized in retrospect, was what was messing with the dual rams that we had originally, and the electric assist that Steve installed, and Leila’s original set up too. No money blown there
Now a days I’m all about a wide quadrant or tiller arm and vectran or equivalent. No oil, very little metal, and very easy to spot issues. Hard or impossible to do on some boats, however.” Kevin Millett

Great Little Tri

I just got this wonderful note from Joe.  I got to sail on his boat in Lake Tahoe back the same week Sierra Cloud had her first sail.

“Hi Kurt! just thought I’d check in and say how much I enjoy your Blog.
The little tri is 26 years old now. Yes I know it is hard to believe.
I don’t baby this boat. It is kept on a lee shore and mostly sailed in
strong winds. She doesn’t look much different than the day I launched it and
shows little signs of wear in all key areas.
I guess at this point we could say the construction is sound.
I’m glad I didn’t go with a “famous designer” with all that I hear
about those boats.
Thanks for the great design. She has given me many years of good times.

Blog on Kurt!

Joe Hollerbach”

echoes @ sand harbor 001

Big Deadlines

Lots to post but big deadlines this week so it has to wait.

Topics for next week include the famous designers sketch laminates drawing. I heard back from the author of the sailing freighter article. I have heard from an Astus tri sailor. New cat pictures from China. Thoughts on all the multis being abandoned.  A new 85 cat design. And more. Deadlines come first.

MACM and Famous Designers

Last week I came across a drawing of some hull laminate work by a famous designer. It was three kinds of stuff done wrong. I sometimes wonder how that is possible, then I remember one thing; MACM, (marine applications of composite materials) conferences. I still say the best that ever existed.  Unfortunately they are no longer held.  Sorry, but IBEX was not even close. And in the 10 or so that I went to over the years, the only famous designers I ever saw were the late Lindenburg, and Roger Hatfield. It seems that most famous designers prefer to go to conferences where they are praised and learn little. I prefer the ones where I am the dummy and I soak it in. It seems like the famous designers don’t feel the need to be the dummy and learn?

Lightning Protection

I had a very interesting time talking to Ewan Thomson while at the 52′ Aerorig cat.   As we know, carbon fiber is a very good conductor of electricity, so carbon masts are particularly vulnerable.  They do not necessarily show the damage.  Black burn against black background.  Ewen works to get the surge down to the ocean while doing as little damage as possible to the carbon mast and the rest of the boat.  I will now urge my carbon mast people to contact Ewen before building the mast.  A few notes that I picked up by osmosis there.

  • Those fuzzy things people use, mostly protect themselves.
  • Ideal is a #2 wire running outside of the mast.
  • If it must be inside the mast, center it equidistant from the mast walls.
  • He uses a number of fusible links to protect boat electronics.
  • Goal is to get the charge into the water with the shortest path and fewest curves in the wire.
  • Because damage is so difficult to see on carbon masts, insurance companies will total a mast upon hearing a lightning claim.

lightnigprotect_g

Wand that goes on top of mast and two kinds of thru-hull grounds.

EwenSailing8

Ewen Thomson Ph.D
President
Marine Lightning Protection Inc.
3215 NW 17th Street
Gainesville, FL 32605
USA 352 373 3485
www.marinelightning.com

Updating the Sailing Cargo Ship

Machine Design Magazine had this. But they have not yet considered a catamaran. This unit they show would need ballast water even more than present cargo ships. Ship ballast is one of the leading causes of invasive species.
http://machinedesign.com/fea-and-simulation/updating-sailing-cargo-ship?NL=MD-04&Issue=MD-04_20150212_MD-04_528&sfvc4enews=42&cl=article_1&YM_RID=CPG05000002211482&YM_MID=1113

 And see from a few years ago a catamaran proposal.  http://multihullblog.com/2012/02/catamaran-container-ship/

On the cat, displacement would be 864,000 lbs per hull.  Draft 7′ and power to go hull speed 1050 hp per hull.  That speed 23 knots.