What performance improvement can I expect from fairing my keel and or rudder? The answer depends on the condition of the keel before the fairing process begins. We have looked at keels that looked simply beautiful, but when templates were applied, proved to be a disaster. One keel that fits this description was very fat which is common. There was a different shape on each side (also common), and the draft was in a different location (also common) on each side. After fairing this keel, the owner reported that there was a bigger improvement than he had ever experienced from new sails, or changing to a different sail makers sails. Most people feel that the improvement is about the same as upgrading a two or three year old set of sails. And unlike sails, once the keel is faired, it won't wear out.
Why do I need to fair my keel? If you don't race, you probably don't need to fair your keel. The keel is simply an underwater sail. However, you can't change keel trim because of different wind and water conditions or point of sail, which makes the keel shape very important. Unfortunately casting large lead or cast iron keels is more difficult than one might think. Many shops that cast lead are ill-equipped to make patterns and molds that accurately reflect the keel shape, and don't have templates to check the finished keel shape, size or thickness. Weight is typically the only variable controlled closely. Cast iron keels are rarely symmetrical or fair, because they are molded in a horizontal position, resulting in one side with a shape , and the other side which is pretty flat. All of this makes fairing a keel important if you are racing.
What is involved to assemble the Compukeel™ Template Kit? The Compukeel™ Template Kit instructions were tested by a sixteen year old girl who knew nothing about templates or keels, and who assembled five large (average length 37") templates in about four hours. The instructions detail the additional materials and tools required. Picture matboard is cut to the correct sizes with a utility knife, wood furring strips are cut to the correct size with a hand saw. The wood furring strips are attached to the picture matboard with a utility stapler. The Mylar patterns are attached to the template assembly with double stick carpet tape and the keel profile is cut with a utility knife.
What is involved to assemble the Universal™ Template Kit? The instructions detail the additional materials and tools required to make templates. Picture matboard is cut to the correct sizes with a utility knife, wood furring strips are cut to the correct size with a hand saw. The wood furring strips are attached to the picture matboard with a utility stapler. The instructions explain several ways to determine the best keel profile depending on the keel material and keel configuration. After the correct profile is determined, the Mylar patterns are attached to the template assembly with double stick carpet tape and the keel profile is cut with a utility knife.
Can I make the templates out of plywood or acrylic instead of picture matboard? Yes, however, we don't recommend it because most people don't have the tools or skill necessary to accurately make them with these materials. First, it is extremely difficult to cut the leading edge wrapped around portion of the template. When sawing this sharp a radius, the saw blade bends, resulting in different profiles on each side of the material. Because you flip the templates over for starboard and port, you will have two different shapes. Secondly, the fairness and accuracy of the keel are only as good as the template. If you cut them out on plywood or acrylic, you will need to spend a lot of time fairing the template to get it smooth. Most people find that this time is more productively spent fairing the keel.
Can I use foam board to make the templates? No, for several reasons. First, it is very difficult to cut the complex radius at the leading edge so that you have the same shape on both sides. Actually, it is very difficult to cut any part of the profile so that it has the same profile on both sides. Second, and most importantly, the surface of the foam board is thin paper, which has no strength and the foam in the middle has no strength. Therefore even if you succeed in cutting templates that have the same shape on both surfaces, when you put them on the keel, because there is no inherent strength, the template will collapse to the shape of the keel.
Can I order the Universal™ Template Kit Assembled? The Universal™ Template Kit provides a range of profiles and instructiions on how to select the appropriate profile for your boat. Because we don't have access to the boat, we can't assemble the Universal™ Templates because without access to the boat, we won't know which profile is best, and therefore can't assemble them.
How long will it take to fair my keel? The amount of time to fair the keel is dependent on the methods and tools used. Our instructions break the process into simple steps so that many people fair their keel in less than fifteen hours. Our new Compukeel II™ instructions are more detailed than the original version, Additionally, we have added information in the Compukeel II™ that can further speed up the fairing process. Experience suggests that if you use the correct tools and concentrate on one variable at a time you can fair the keel quite quickly. The wrap around feature of our templates reduces the judgement required when fairing the keel, further speeding up the fairing process.
I race a J/22 one-design, which model should I use? The class rule on the J/22 doesn't specify a leading edge radius. The computer can fill in the leading edge area, but in doing so creates an extermely fine entry. What we have done on the model CKD is replace the first five class rule data points, and added a leading edge radius so the resulting profile has a much better entry and is very fair. This change makes the keel perform much better than a keel faired to the class rule minimum, whether racing one design or in PHRF with or without a genoa.
What is the difference between the Compukeel™ and Compukeel™ II? The Compukeel™ is the original Computer Keels product, which was created almost 25 years ago. During that time, we have answered many questions concerning keel fairing, and performance issues, and in the Compukeel™ II have tried to incorporate the additional information that was provided to those questions. The Compukeel™ II has additional information on the patterns (chord percentage markings and additonal trailing edge configurations) that can simplify and speed up the fairing process. It also has more detailed keel fairing instructions that list several specific material recommendations, and incorporates feed back from users to speed up the fairing process. It also has a precision ruler for locating the templates and several performance enhancing tips that many people have found beneficial.
What tools do I need to make the templates? The templates are fabricated using a hand saw, ruler, utility knife, and utility stapler.
What tools do I need to fair the keel? You will need a buffer/sander/grinder, an orbital or random orbital sander, a SurForm file, a ruler or straight edge, and plastic filler spreaders. On keels that have a lot of lead to be removed, a power plane quickly removes the lead high spots.
What materials do I need to fair the keel? The Compukeel™ II instructions make specific material recommendations, the other instructions generically list the materials to be used.
How quickly can I get my order? We normally ship kits on Thursday if they are in stock. If we are out of stock, we will order and then ship when we receive the product or the following Thursday whichever is sooner. For an additional charge we can get you a kit sooner. Assembled templates take longer because we need to assemble them, and the UPS shipping takes longer.
Do you have templates for rudders? Compukeel™ Templates and Template Kits are available for some rudders. The Universal™ Template Kit can be used for rudders for which a Compukeel™ Template Kit isn't available.
How much material will I need to add or remove? The amount that is either added or removed can in large measure be controlled by you. Most lead keels after they are faired have very little fairing material on them. If you want to get to the absolute minimum, you may need to remove between five and fifteen pounds of lead on some boats. Cast iron keels will require more fairing material because it isn't practical to grind or sand cast iron, but you can control the amount that is added.What is the difference between the Compukeel™ Model CRD and CKD? The model CKD stands for Computer Keels Design, and the model CRD stands for Class Rules Design. The Computer Keels Design is a hydrodynamically fairer profile than the class rules (or original design) and/or provides performance improvements for some points of sail in certain wind and water conditions.
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: firstname.lastname@example.org
Updated March 1, 2005 © 1997-2005 Computer Keels Company All rights reserved ()