Hey guys, Hull speed ???? Pat Ford Port Washington, WI Seabiscuit 3692 ----- Original Message ----- From: Sneddon, Keith To: [email protected] Sent: Monday, August 27, 2007 2:29 PM Subject: RE: catalina27-talk: a whole week!
Hmmm. It depends. If you are already at hull speed, opening the slot will not make you go any faster, and you will probably lose a little height so, in that case, I might live with a little backwind on the main. If, however, you are below hull speed, you might try opening the slot, and see how it affects your speed and pointing ability. You could also try easing the jib sheet just enough to take the bubble out, and/or bring the car back a little to let the leech of the headsail curve away from the main a little bit. It could be the cut of your main (too full fwd), or you could try a different balance of outhaul/vang/cunningham. I caveat these statements with the fact that, although an avid racer (dinghies and other peoples boats), I do not race on my C27, so the guys that race them could probably give better advice. Keith Sneddon #4760, "Are We ThereYet?" ------------------------------------------------------------------------------ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, August 27, 2007 2:54 PM To: [email protected] Subject: RE: catalina27-talk: a whole week! Keith ... so, when I've had a 135 or 150 or some such up, I have a "bubble" in toward the leach of the main, even with it centered, telltales flying correctly, and flattened out pretty good. I take this as backwind off the genoa. So if I let go the backstay and allow the forestay to sag off, I'm thinking that opens up the slot a bit and maybe fixes the main? And will that affect my ability to point? Tom "Sneddon, Keith" <[EMAIL PROTECTED]> Sent by: [email protected] 08/27/2007 01:39 PM Please respond to [email protected] To <[email protected]> cc Subject RE: catalina27-talk: a whole week! I agree with Tom on most of this, except; on mast head rigs (like a C27), the backstay adjuster is mostly to adjust the sag of the forestay, which influences the width of the "slot" between the headsail and mainsail, whereas on a fractional rig (like most J- Boats), the backstay adjuster will really bend the upper tip of the mast aft, particularly if the mast section is tapered up high. The difference is that, on a masthead rig, the forestay directly resists the backstay tension, and on a fractional rig, it reacts the force of the backstay from a lower attachment point, which bends the mast. Keith Sneddon #4760 "Are We There Yet?" ------------------------------------------------------------------------------ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, August 27, 2007 2:21 PM To: [email protected] Subject: RE: catalina27-talk: a whole week! We really need Tim or Chris or Phil or someone to comment on this, but ... I don't think you can really get a C27 mast to curve by adding tension to the backstay adjuster. The thing is just too think an extrusion. My understanding, which has undoubtedly has as much opportunity to be wrong as yours, is that rake and backstay do two different things. Rake adjusts the turning moment of the sail combination to the turning moment of the hull. It's kind of a dynamic thing since the turning moment of the hull changes with healing, and the turning moment of the sails changes with what sails you have up and how they are trimmed. So you're trying to hit an average. The idea of using the backstay adjuster to bend the top part of the mast backwards is to change the shape of the main. Why you do that and what it accomplishes I'll leave to others. Tom "Joe McCary" <[EMAIL PROTECTED]> Sent by: [email protected] 08/27/2007 12:19 PM Please respond to [email protected] To <[email protected]> cc Subject RE: catalina27-talk: a whole week! Well, Tom, You asked for a week to take you mind off other things as well as your tie. So you can't complain except for the shredding bimini and sail cover. I am glad your mast rake has helped your performance. I am wondering along the same lines if using the adjustable backstay adjuster if it has some of the same effects? Going to weather my understanding is to add on more backstay tension (moving the mast aft and adding weather helm) and when off the wind to release tension. To me this seems counter intuitive and backwards. Am I wrong (would not be the first time)? Joe McCary Aeolus II #4795 West River, MD [EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Well, for a midwest August it was sure a windy week. Couldn't even sail Monday. Tuesday and Wednesday I was rail down at hull speed with just a working jib up. Thursday I actually used the main. Friday a storm came through and shreaded my bimini and main sail cover at the dock. Weekend was back to typical August sailing ... i.e., hot and slow. Re a previous post on mast rake ... I finally got the opportunity to retune the mast. Pulled it forward a good bit, and she sure sails a lot better. I think I need to go another inch, but till I can get out in conditions where I'm healed at 15-20 degrees with BOTH a main and jib, I can't really tell. It's been a funny midwest season. I bought a new 135 this year so I could sail better in light air. It's been up twice. I've mostly been using an old working jib, and often a reefed main. Tom 6219 Different Drummer
