From - Mon Mar 10 13:18:05 1997 Received: from beasley.cisco.com (beasley.cisco.com [171.69.2.135]) by cheerios.cisco.com (8.6.10/8.6.5) with ESMTP id MAA22009 for ; Mon, 10 Mar 1997 12:09:32 -0800 Received: from bolero.rahul.net (root@bolero.rahul.net [192.160.13.1]) by beasley.cisco.com (8.8.4-Cisco.1/CISCO.GATE.1.1) with SMTP id MAA01125 for ; Mon, 10 Mar 1997 12:09:30 -0800 (PST) Received: from waltz.rahul.net by bolero.rahul.net with SMTP id AA28733 (5.67b8/IDA-1.5 for ); Mon, 10 Mar 1997 12:09:26 -0800 From: Randy Devol Received: by waltz.rahul.net (5.67b8/jive-a2i-1.0) id AA12749; Mon, 10 Mar 1997 12:09:25 -0800 Date: Mon, 10 Mar 1997 12:09:25 -0800 Message-Id: <199703102009.AA12749@waltz.rahul.net> To: cliff.sojourner@cisco.com Subject: Blade Runnings 7 X-Mozilla-Status: 0001 Content-Length: 5594 Blade Runnings Volume 7, September 29, 1996 Hi! (If you received this email directly, you are on the unofficial Trifoiler email list I maintain. About once per month, (or more often if the news is worthy) I try to update list members with information about the Trifoiler and what I have been doing with Blade Runner. If you do not want to be on the list, let me know.) >From Blade Runnings volume 6: ... on a day that was supposed to be sailing JUST for fun (no race), the second worst thing imaginable happened. Blade Runner broke in the middle of the S.F. Bay, capsized, nearly sank, ... That was two months ago. You may have been wondering if I died in a car crash or something. Well, not yet (knock on wood). I have been putting miles under my wheels, though. I have towed the boat just about 1000 miles since it was repaired, and that was all without launching the boat once. During those weeks, something wonderful happened: Several other FS Bay sailors bought Trifoilers. So where once there was one, the now are *FOUR*! So, with a few telephone calls and email messages, we organized our first regatta. Well, it was not really a regatta. It was really just an excuse to all meet and go sailing. We chose Saturday, September 28'th. The forecast for Chrissy Field was for 15-20 knots from the west, with a flood tide until 2:45 or so. The conditions were predicted to be near perfect, and they were. Three of the four local boats made it to the beach. JD from the "local" dealer, Windtoys, brought a boat down but did not set it up. It was great to see the dealership out there answering the 1000 questions that always come up from the public. He also helped everyone launch and land without scraping their foils. Very nice. Much appreciated! The first boat launched at around 12:00 in about 8 knots of wind. In that much wind, a Trifoiler will sail on a reach at nearly 8 knots, but it won't get up on the foils. So while I sat on the beach, eating my lunch, the new owners were out on the bay getting very wet, and sailing along at a respectable speed. (New owners! Sheesh!) By 1:30 the wind was 10+ and all three boats were on the foils, enjoying the flat water. By 2:00 the wind was strong enough to take passengers along. By 3:00, the wind was still rising and the chop was starting to rise. About this time, I found Cliff downwind about 1/4 mile, turned down, and quickly closed the gap. Like any two boats on approximately the same heading, Cliff and I had a little race toward Sausalito. We were about 50 feet apart, doing 35 mph. It was great! I started out faster, then Cliff gained on me. It was great! But it only lasted about 15 seconds because we were approaching the Wind Shadow of Yellow Bluff. The wind was still increasing and Blade Runner was getting overpowered. Here is another way Trifoilers are very different from most boats. I think I understand how a Trifoilers behave when overpowered. (Dan, correct me if I am wrong!) The leward foil must provide upward lift to keep the boat upright. At the same time, the windward foil must pull down to keep the boat from tripping over the leward foil. However, the amount of lift needed from the two foils is very different. Since drag is a linear function of lift, there is much more drag from the leward foil than the windward foil, which tries to turn the boat downwind. At speeds lower than 25 mph the rudder can easily keep the boat on track, but at higher speeds, the rudder rides higher, and rudder aeriation (air getting sucked down the trailing edge of the foil) both work to disable the rudder, which makes it unable to keep the boat sailing in a straight line. This was definitely the case when racing with Cliff. He caught up with me too easily because I had the rudder turned at a 10-15 degree angle the whole time. My sails were trimmed to perfection and generating lots of side force that had to be be countered by the foils, which generated lots of turning force, which had to be countered with the rudder. Cliff had eased his sheet, spilled some of the wind and thus avoided throwing his rudder so far over. His sails were producing less power but also much less drag, so he was going faster. Shortly after this run, he reefed his sails and reported that it was much easier to sail. So, when I have to keep the rudder turned just to go straight, either it is time to ease the sheet, drop the stern a little, or reef the sails. Cliff and I had so much fun racing, we are getting together again in about a week. I have not contacted the other Bay Area owners, but Larry in Reno may make it down for that one. If the wind looks good at San Luis reservoir, we will go there. If the wind looks too light, I will try to talk Cliff and Larry into going back to Chrissy Field. (Are you listening, Robert?) Finally, I have changed Internet Service Providers. Please note my new address, below. This will allow me to set up a real list server and a web site. Stay tuned for information about those in future months. -=O=- Randy ////||||||\\\| randyd@rahul.net _______\o_____//////||||\\\\| / Blade Runner ///////||\\\\\|===>\ Trifoiler Hull #42 ||______________________<=====||====>\__> ~~ ~~ ~~ ~~ ~~ || ~~ \__> ~~ ~~~ ~~~~ ~~~~~ ~~~~~~ ~~~~~ ~~~~~ ~~~~~~ ~~~~ ~~~~~~ ~~~~