The performance improvement from fairing the keel with the patented, wrap around Compukeel™ Templates is very noticeable on J-boats. Most J-boats' Compukeel™ Templates use the Class Rule Minimum (CRD) dimensions. Computer Keels has developed alternative (model CKD) designs for the J/22 and J/24 that are permissible under the class rules. The J/24 model CKD greatly aids upwind performance when using the 150% genoa in higher wind ranges. Many owners feel that it provides many of the benefits of moving the keel forward without the hassle, or further accentuates the impact of moving the keel forward. It also allows sailing several degrees lower on down-wind legs with equal or improved boat speed in all wind conditions. Keel fairing is significantly faster with the model CKD and for 1978 through 1981 boats removes less lead than the model CRD.
The class rules on the J/22 do not specify a leading edge radius. The J/22 model CRD lets the computer create a fair curve with the data points but it has a very fine entry. The J/22 model CKD uses known leading edge radius' and the first several data points to create a hydrodynamically fairer entry, making the keel less susceptible to stalling upwind in heavier air conditions, or when racing in PHRF with a genoa.
The performance improvement from fairing the J/35, J/29, J/30, and J80 is very significant. On the J/29 and J/30, additional instructions explain keel chord length changes to significantly improve performance.
Compukeel™ Templates and template kits are available for most J-Boats
Other boat owners have used the following Universal™ Template kit chordlengths. Owners' wishing to simply check the keel should only purchase the shortest and the longest chordlengths. Owners desiring more templates should specify additional chordlengths between the sizes listed in the table. There isn't a "correct number" of templates required for fairing the keel, but rather what the person fairing feels comfortable with. Most people like a template for each 10" to 20" of keel height. For available chordlengths, pricing and an Universal Template™ Kit Order Form follow this link.
Universal™ Template Pattern
UNIVERSAL™ TEMPLATE KIT PATTERN LENGTHS BY BOAT
|Boat Model (click on boat to order)||Chord lengths used||Keel type||Price, plus delivery|
|J/28||45", 53", 61"||Lead||$230|
|Jenneau Sunlight 38||53", 61", 73"||Cast Iron||$260|
|Jenneau Attalia||29", 57", 65"||Cast Iron||$240|
If your boat has a lead keel and you would like a quotation for a Compukeel™ Template kit or assembled templates, please send, or e-mail the keel offset dimensions. These usually are available from the designer or manufacturer. If your boat has a cast iron keel, or the keel-offset data isn't available, you will want to use the Universal™ Template Kit.
If you would like assistance in selecting patterns for the Universal™ Template Kit, measure the keel chordlength at the top and bottom of the ballast, and the vertical distance between these chordlengths. Knowing the vertical distance between these two measurements will help determine the number of templates. To measure the chordlength, hook the end of a tape measure on the trailing edge of the keel. Pull the tape measure forward to the point of maximum keel thickness. From the point of maximum thickness forward, the tape measure should pulled forward parallel to the centerline of the boat. Sight across the tape measure to determine the location of the leading edge of the keel. Send us these dimensions in our Universal™ Template Kit patterns to use request form for a a recommendation on which patterns to use if you are having trouble deciding.
Follow this link for available chordlengths, pricing, and order form for the Universal™ Template kit.
If you have any questions, contact us using our on-line inquiry form, write us at COMPUTER KEELS COMPANY, P.O. Box 39757, Edina, MN 55439 or call (952) 829-5670, or e-mail: email@example.com
Updated November 7, 2014 © 1997-2014 Computer Keels Company All rights reserved