I was stumbling around looking for photos for the new composite construction manual. Found this picture from 1980. My first boat. 31′ then. Tim Ryan steering and Dennis Hough on sheet. Hat Island race. Courtesy John Marples.
I always have the notion that I am the only person who ever reads this blog. Matthew tells me however that it is gaining about 20% every month. And it just got a nice write-up in the French Multihulls World magazine! Thanks everybody. I have a list of interesting upcoming topics that I will do.
This new 20/21 foot shuttle cat has begun production at Zuhai, China (near Macao). It is especially intended as a chase boat for rowing teams or as a mini shuttle. Unit #1 has a bit taller cabin than designed.
This KHSD 36 daycharter cat has just begun to charter out of Marathon, FL.
I just got pictures of new KHSD 32′ charter cat in production at Goa, India. They are next doing a KHSD power trimaran for production.
We finally got some Adventure Cat and Adventure Cat 2 photos. They operate out of San Francisco.
One of the rules of plastics is that they all degrade in sunlight. The nets on my 40′ x 36′ trimaran seem to be the exception to that rule. My Net Systems knotless black polyethelene nets have been flawless for some 15 years. They do need to be tightened every season.
I give them the leap-off-of-the-hull onto them every so often to impress the crew. I recall the failure point some years ago during the Shaw Island Classic when Mark Evans leaped into the net. The cast padeye holding the net exploded. Many thumbs up on this product.
Not all the sets have this yet, but according to people who use this detail, it supposed to be the best way yet to attach a window to a boat house. I have a PDF of it also that will be added when I get a chance. Or I can email it.
Its kind of a mini Sarabi.
We just got the bids in on the new carbon fiber unstayed mast for Alex’s KHSD 45 catamaran being built in Blaine, WA. It is what we call an aeroesque mast. Same general idea as the aerorig, but updated.
I’m sure the safety of these masts will make them the future of USCG certified sailing cats. The Coasties just need to see the FEA study to accept them.
One of my earlier cruising cats was brought to my attention recently. I flew to Perth to build the hulls back in ’86 was it? They have cruised everywhere and it still looks great. Ply/epoxy in CM. http://www.boatpoint.com.au/boats-for-sale/boatdetails.aspx?R=9519130
Every couple of years I have someone ask me why my cat designs need to have aft beams. This occured again last month. They seem to have the tone that there must be a structural secret I just have not figured out yet. I did just get this picture. “Why can’t you do a beam like this? Ask them how they did it.”
People. Remember where I always say “with enough carbon and enough money, you can probably do anything you want to.”? There are limits. They probably think a sleek cat beam looks like this.
It actually looks more like this. The boat salesmen hide a beam like this so it will look thin or even gone.
That is compared to a standard beam. Like this…
So why don’t I catch up and do the flat beam? Remember how I always talk about efficient cats? Look at this.
The tools we designers use to compare beams are the moment of inertia “I” and section modulus “SM”. (assuming shear is satisfied) Suppose the regular beam is 12″ x 36″ by 0.1″ thick laminate. That regular beam has a SM of 99 in^3 (inches to third power) and a moment of inertia I of 2104 in^4.
In the horizontal mode beam, it only has a SM of 44 and the I is only 272 in^4. To get more strength and stiffness it must be made thicker and heavier. Even if the horizontal beam laminate is made 7 times thicker and 7 times heavier, it only has the same strength as the regular beam and still only a third of the regular beam’s stiffness. The flat beam boat vendors hope you don’t know or care enough to appreciate the difference. They can’t claim efficiency and still have horizontal beams.
Scott MacIndoe of Fiberlay recently noted that especially due to petroleum costs increasing, boatbuilders should expect sharp increases in boatbuilding materials in the next 6 months or so. If you are planning a project, get the materials now ahead of the curve.
I did just get the last of the orders out today from the backlog that built up when I was gone. Its in the mail.
I have usually always used blocks bolted to boards to allow the hold-down lines or the lift lines to function. In the same way that spectra wraps now can replace a track and car on the boom, I propose similar for a board. On a smaller board you can use a Harken C 8882. On a slightly bigger board you could use that part cut down the center and attached to both sides of the board. On big boards, I’m experimenting with a faired hole using high strength bog. I will see if teflon coating or graphite coating helps. I assume it will not work quite a well as a block, but be much cleaner.
Some new pictures of Jim Dory’s 30′ cat have appeared at http://www.flickr.com/photos/jdory/5498545909/in/set-72157625973914417/
This boat was built and launched near Nome, AK. After it was launched, it was tied up in the harbor. During the night, in a gale, that barge broke loose and came to rest against it. There was damage, as you can see. But try to wrap your mind around how little damage actually occured. It was the fender for a barge during a gale.