Originally Posted by scarlet
So... I want to add some "tell-tales" to both sails to help me get a feel and understanding for sail trim. So, I have 3 related questions..
1. My husband bought some.. they are a plastic streamer type material.. that stick on to the sail.is that ok? or is there a better, more effective type out there to use...?
2. where and how many should be placed on each side of the sail?
3.do I need to remove the sails completely? or can I just partially raise the sail, and attach them?
Thanks in advance...
If you don't know where to stick them you need to read up a bit more and ask some questions. Follow the link provided by OldFrog and pay particular attention to the section on boundary layers and bubbles.
I disagree with the article on only needing tells on the main's trailing edge especially for a beginner.
The tells let you see what is happening to the airflow on various parts
of the sail. The mainsail can be very complicated to trim and trailing edge tells only tell you what's happening as the airflow departs the sail. If you plan to get good at this the more info you have (to a certain point) the better.
The mainsail could have halyard
tension, mainsheet, traveller, outhaul
, vang, cunningham and adjustable backstay all influencing its shape. You could be stalled at the bottom and drawing at the top for example.
Having tells on the sail can help you verify your theory why the trailing edge tells are not behaving.
The genny has halyard
tension, genny car position (sheeting angle) and some racing
gennys will have a cunningham.
You clearly don't want the sails looking like tinseled Christmas
trees and it depends on the size of your sail.
First - Keep the trailing edges of any tells away from sail seams - it is annoying when they get stuck - especially in low winds when you are trying to get the sail as efficient as possible.
Genny - Definitely 3 sets vertically. One in the vertical mid-point, one a little less than 1/3 down and one a little more than 1/3 up. Don't forget to stagger them vertically by a couple inches so you can see both sides. For and aft - depending on the roach you may only need two sets - a 150 genny might take 3 sets. The aft most one should be just aft of the "normally" deepest part of the roach.
Mainsail - Vertically the same as the genny. Again depending on the roach length you may need 2 or 3 sets - 2 is probably ok. 1 just at aft of the deepest part of the sail (usually the first third) and the second pair split the difference to the leading edge. The trailing edge flies are key IMO and for them I always prefer yarn over tape.
mainsail tapes can also help figure out genny/main interaction in the slot.
I also prefer yarn over tape everywhere as I fell the yarn is more sensitive and the "flate tape" resists flying up and down a bit more. The tape dries faster after rain and lasts longer.
Whew - TMI, sorry...
Originally Posted by OldFrog75
The plastic streamers will work on the mainsail. You can attach them to the ends of the battens.
Yarn works better for the jib. Attach 6 inch pieces with round one-side stickies on both sides of the sail. Most boats I've been on attach the jib tell tales further from the luff than indicated in this article and I've never seen a boat with telltales on the leech of the jib but it's a start:
WB-Sails - Aerodynamics
Everything you need should be available at your local marine
I took the NorthSails weekend sail trimming seminar and would recommend it to anyone.
Their website also is great and has live graphics demonstrating each concept
North Sails: Mainsail Trim
What I really like is they lay out a "sequence" for adjusting the sails so there is some logic behind it.
I sailed with a guy (finally gave up) that would sheet the main on a beat with the mainsheet and leave the traveller locked. He had no idea what the mainsheet did vs. the traveller and was super stubborn. I finally left that race
boat and refused/refuse to sail with him to this day.
When you take the course you get 2 CDs. One has a sailing simulator where you can input different conditions and then sail and trim a virtual boat around a course trying to achieve maximum boat speed.