The AmCom Design and Manufacturing Show is going on tomorrow in Bellevue, WA. See http://www.amconshows.com/ShowInformation/SeattleWA/tabid/1011/Default.aspx
Visit with local manufacturers of many items useful to building boats. Including composite bearings. Free parking from the website or I stuck the car at Bellevue Square. Sorry Kemper.
Category Archives: New Designs
Internet Down Today
It seems that the website and all email are down today. I will try to contact server and find out why. They say hardware issues. Its like a 5th world country here in Seattle sometimes with access.
Archive Pictures
I I had to dive into deep offsite archives looking for the Kobayashi 53 catamaran design files. I also found a wealth of old photos. Here with ocean sailor Konrad Kalpen on my tri. 1994 maybe.
Laminate Weights
I forget where this came from. Enjoy.The more enlightened builders can use metricalc to convert. Someday this will be a spreadsheet.
USCG Passenger Vessel Matrix
I forget who gave me this now. It was a few years ago but looks still relevant. I put it in exactly square…..
All I do anymore is email. Am going to try to hide out next week and do design work. Understand if I keep the email replies brief. And please just tell me what you want and how you want me to accomplish whatever it is.
Estonian Powercat
Nice write-up about the Estonian KHSD 44/46 powercat in Multihulls world. http://issuu.com/multihulls-world/docs/mhw123/search?q=p32 Enter the search word “arteran”
And at http://www.artcat46.com/en/
I have mixed feeling about this. It looks beautiful still. They have added so many goodies downstream that the payload is now close to zero. It began as an efficient green power cat for ocean voyaging. The mission gradually crept to being a party barge and filling as much of the space between the bow and and transom as possible. I often see this in people new to catamarans. Instead of declaring a cabin size and letting me put the right size of sled under it, they pick hulls first and then expand to fill up the “wasted space”. Up high are the worst seats on the boat in waves. It has now become a flat water vessel. And will surely trim aft. Discouraging. Maybe I know nothing about the market and it will sell like crazy.
Alii Nui Construction and Launch (2)
Alii Nui Construction and Launch
When I sailed on the 65' Alii Nui they had this great brochure on board. I finally scanned it and got permission. A kind of big pair of scans, but worth it.
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Why Boards instead of Keels
I am a big advocate of boards instead of keels on multihulls. I understand the preponderance of production multihulls have keels. And boards can mess up the interior. The big deal, I think, is the greater lift that a board generates. When I got new computer a while ago, I had not gotten around to downloading Dave Vacanti’s Loft 97 foil creating program again. He has a free demo of it. I urge you to compare keels to boards on your own.
Keep in mind that nothing else will push you windward except lift.
See http://vacantisw.com/ Go to the free downloads.
For example lets compare 16 square foot foils. Same foil family, NACA 00. For simplicity, no sweep.
Assume a board with 2′ chord and 8′ draft. At 5 knots the board generates 800 lbs of lift. At 20 knots, 12,000 lbs of lift.
Next, a keel of 2′ draft and 8′ chord creates 120 lbs of lift at 5 knots, and 2,400 lbs at 20 knots.
Now look at a common 1′ deep keel. At 5 knots, 35 lbs of lift. At 20 knots, a mere 550 lbs of lift. People. Again, nothing else will push you to windward except lift.
And as I tell my catamaran customers with keels, take a cell phone with a marine towing service on the speed-dial. If they run aground, a mono can kedge off of the mast and get free. A trimaran can chase everybody onto the ama and get free. If the tide is going out, a cat with keels will spend the next several hours there. Period.
Finally, if you stuff it up on a rock, with a keel you must haulout to fix. With a board you can keep sailing as you repair the board.