Last summer I got to design some catamaran hulls for an oceanography drone built by Advanced Undersea. It was required to be alloy. I would have preferred roto-molded, but what do you do? About 8′ long as I recall.
https://www.youtube.com/watch?v=iH5lV91tXp4
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”
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.
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?
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.
Wand that goes on top of mast and two kinds of thru-hull grounds.
Ewen Thomson Ph.D
President
Marine Lightning Protection Inc.
3215 NW 17th Street
Gainesville, FL 32605
USA 352 373 3485
www.marinelightning.com
Transport when he gets there.
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.
I have had my differences with Gary over the years. He does not believe in the design process, weight studies, nor structure engineering, as nearly as I can tell. He does do amazing work I have to admit. I was blown away at how wonderful the workmanship was. This has to be one of the most luscious interiors I have ever seen on a cat.
I had the occasion to visit this nearby 52′ catamaran project on a kind of forensic expedition. I always thought it odd that it looked so 70’s even though it was designed in the 90s. I have always been amazed that it used a space truss to support the unstayed mast even though it has a substantial bridgedeck and cabintop right there. See Prior Art at http://www.multihulldesigns.com/pdf/aero56story2.pdf. And I was shown some astonishingly bad laminate design. More on that next week when I get these deadlines met.
I had not noticed that my old tri Geko had a writeup just before last New Years. On Face. He plumbs different depths than I do, but appreciated.
JJ Iruka Saitoh-Car’eeTrimaran Gecko
December 28, 2014 ·
https://www.facebook.com/permalink.php?story_fbid=1551778328397283&id=328374460702512