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Capri 25 Keel Templates

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jmadd
1st Mate

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USA
85 Posts

Initially Posted - 11/21/2007 : 13:20:08

Has anyone had any experience with using Computer Keel's keel templates for the Capri 25?

They list three on this page:
http://www.compukeel.com/uniboats.htm

Reshape Capri 25 18", 26", 35" Lead
Larger Keel Capri 25 26", 38", 49" Lead
Custom Capri 25 19.25", 26.5", 33.75" Lead

A couple years back some guy told me that he templated his Capri and it made a huge difference.

I'm going to ask them about the three templates but wanted to know if anyone had any experience with this.
Best Regards,
John

Edited by - on

saribella
Captain

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USA
286 Posts

Response Posted - 11/21/2007 : 23:43:24

I would like to know as well. JMadd, when you receive some information or try a set of templates, please post the results.

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jmadd
1st Mate

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USA
85 Posts

Response Posted - 11/23/2007 : 14:50:02

I received a response quite quickly from Larry at Computer Keels. I requested permission to post his response here, and he asked that I give him a few days to update it with some additional details. I'll post it here when he gets back to me.

Edited by - on

Ericson33
Admiral

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USA
892 Posts

Response Posted - 11/24/2007 : 00:59:31

I will go in as a partner if we can use the templates at a lower cost than buying them myself.

Let me know?

Edited by - on

jmadd
1st Mate

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USA
85 Posts

Response Posted - 11/25/2007 : 12:29:27

Here's the response I received from the Computer Keels folks.
From reading their license agreement, it seems that use of the
templates purchased is limited to one person/boat.
Posted with permission from larry at computerkeels dot com.
Regards, John
-------

Thank you for your interest in Computer Keels Template Products for your Capri 25. The following should assist you in choosing the correct template option for your boat.

Winners understand that the shape of the keel is as crucial to boat speed and pointing as the proper sail shape. The keel provides the major reactive force that allows the power created by the sails to move the boat efficiently. Boat performance suffers from errors in either the keel or the sail shape. Although your keel is molded fiberglass and accurately made, other owners have found that a slightly different entry reduces keel stall in heavier air and slop and chop, providing better upwind performance.
HOW YOU CAN IMPROVE YOUR PERFORMANCE
Computer Keels' patented products make it practical for you to make very accurate keel templates, and have a well-shaped, symmetrically faired keel. The product designs minimize the skill and tools required to make accurate templates. Computer Keels provides patterns and detailed instructions that explain how to make templates from picture mat-board reinforced with wood strips. This construction technique produces very accurate templates that are quickly fabricated with a minimum amount of skill using a hand saw, utility stapler, ruler, and utility knife. The keel refairing instructions explain the process so that most people can fair a keel. Much misinformation exists on keel fairing; it isn't as difficult or mysterious as people think. A power combination grinder/sander/buffer and an orbital sander are needed for the keel fairing. The easiest way to fair the keel is to plan to spend several hours per session, allowing time between sessions for materials to cure and harden. The keel fairing instructions will help discuss the job intelligently with the person doing the fairing if you choose not to do the work yourself. Also included is information that explains how to reduce or eliminate keel blistering.
WHAT YOU WILL NEED
Computer Keels offers several products for the Capri 25. Catalina at one time suggested that they would be introducing a Capri 25 II which would solve the heavier air problems the boat experienced. They published a drawing suggesting making the keel larger by adding material to the leading edge of the keel. Owners who tried their recommended changes found that the boat performed better in heavy air, but became a complete disaster in light to moderate air. The fact that Catalina never produced the Capri 25 II suggests that this probably isn't the best approach. However, if your average winds are greater 15 knots, you may want to consider enlarging the keel. The potential problem with enlarging the keel is that PHRF handicapping committees have difficulty knowing how to deal with keel modifications. One suggested that it changes the rating by 18 seconds per mile. Eighteen seconds per mile makes good advertising copy for changing a keel, but probably won't make the boat that much faster. Most people choose not to follow this course, although their is a listing of Universal Template pattern lengths on the order form to implement this alternative.

The other alternative is to modify the aggressiveness of the factory keel shape to improve heavier air performance. Most owners choose to simply refair the keel with a less aggressive shape. This option has an almost infinite set of possibilities. The first boat to implement this option significantly changed both the entry configuration and the total keel thickness. The owner felt, and others agreed that the boat was significantly better in heavier air, but light air upwind performance and downwind performance in all conditions was negatively impacted. Other owners played with the combination of changing the entry configuration from minor to something less than the first boat faired using the Universal Template Kit ( with either 1, 2, or 3 patterns) to make these changes. This product package makes sense for those who really want to immerse themselves in the project and feel that they want or need the ability to finely control the changes. It also will probably take the most time to implement, and be the least expensive template cost option.

After working with many owners on using the Universal template package, and after very successfully developing a new style template/fairing tool for another boat with similar problems, early in 2002 we introduced the Capri 25 Custom Keel Templates From the feedback of users that have used the Universal Template Kit, and their results, we have created what we feel is the best shape for improving heavier air performance, but at the same time not giving up light air performance. There are three templates that have the designed keel shape on the forward part of the keel along with the recommended keel shape. The partial templates fit on the keel, and you simply add material where the template isn't touching the keel. Instructions explain how to add material and fair the forward portion of the keel to the new shape relatively quickly. The Custom Keel Kit includes some of the Compukeel™ ll information and a checklist of items to prevent or eliminate performance problems resulting from the keel and or rudder along with other boat preparation details that many people overlook. The Custom Template Kit is $275. plus shipping. Computer Keels Company can assemble the Custom™ Template Kit into ready to use Assembled Custom™ Templates for an additional $100. plus shipping. Because of the size of assembled templates, shipping is more than for the kit.

The Universal™ Template Kit has hydrodynamic profiles included are similar to those on many of the best performing boats. The instructions explain how to measure your keel to select the appropriate profile for your boat. After selecting the keel profile, instructions explain how to make templates using picture mat board reinforced with wood furring strips. Most people use from one or three templates for the Capri 25, three being the most commonly purchased choice before introduction of the Custom Keel package.. Each pattern (chordlength) contains multiple profiles, precisely drawn in ink on Mylar, that cover the range of keel thickness from very thin to very fat. Three patterns to make templates to simply change the entrance keel shape costs $180., plus shipping.

Three patterns to enlarge the keel to the size recommended by the factory costs $210., plus shipping. .A listing of the chordlengths used on different boats, available chordlengths, pricing and an order form are at http://computerkeels.com/uniboats.htm , or can be securely ordered online at www.computerkeels.com/univers.htm," target="_blank">https://secure.iaxs.net/www.computerkeels.com/univers.htm, or you can call 952 829-5670 or e-mail info@computerkeels.com.

Fairing rudders has less impact on sailing performance than the keel because they are made of fiberglass, are much smaller than the keel, and the angle of attack can be changed to get the desired response. Most people find that simply rounding off the leading edge, squaring off the trailing edge and block sanding or filling the waviness and hollows provides the majority of improvement available from fairing a rudder. Some Capri 25 owners have found that altering the balance of the rudder improves helm feel and makes the boat easier to sail upwind. Call for further details.

THE RESULTS
The following regatta results demonstrate the significance of the keel on J/24 performance. In a six-race regatta, the winning skippers of each fleet (J/22, J/24, SONAR, MORC, PHRF, etc.) raced in J/24s to determine the skipper of the year. Nine boats were rotated among skippers after each race. Every race was won by a boat having a keel faired using a template. The top three boats had keels faired using Computer Keels patented templates with an average finish of 3.25. The average finish for the non-Computer Keels faired boats was 5.75.

The 1987 MORC International Overall champion faired his keel using Computer Keels patented templates. The 1990 Catalina 27 National champion faired his keel with Computer Keels patented templates. The 1992 J/24 Mid-Winter champion faired his keel with Computer Keels patented templates. Many division winners at Key West Race week have faired their keels with Computer Keels patented products. Many division winners at the various NOOD regattas have faired their keel with our patented products. The 1996 and 1997 LOWISA overall winner and J/22 division winner used Compukeel™ templates to fair their keels. Isn't it time that you faired your keel with templates for improved boat speed and pointing? If you have any questions, please write COMPUTER KEELS COMPANY, P.O.Box 39757, Edina, MN 55439, call (952) 829-5670, or e-mail info@computerkeels.com or http://computerkeels.com

Thank you for your interest in Computer Keels Products for your boat.

Copyright © 1982-2007 Computer Keels Company

Edited by - on

joearcht
Navigator

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USA
241 Posts

Response Posted - 03/11/2009 : 20:01:10

Did anyone ever try these templates?

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Ericson33
Admiral

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USA
892 Posts

Response Posted - 03/15/2009 : 13:05:10

if someone has the points for the keel I can plot off the archs then someone can take these to build a wood template.

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joearcht
Navigator

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USA
241 Posts

Response Posted - 03/16/2009 : 08:48:50

Chris,
I kept researching after posting this question. What I learned is that there has been a tremedous amount of research and documentation into airfoils by an organization that goes by the acronym of "NACA". I eventually found a number of computer programs that will compute the NACA profiles for any chord length. So I think what I'm going to do is plot a NACA 0010 and NACA 0012 profiles (these seem to be the most common for sailboat keels)for a number of chord lengths. I plan to develop the data in an AutoCad file then plot a sample and see which profile most closely matches my keel. I'll share the results with the forum when I get this done.

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Ericson33
Admiral

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USA
892 Posts

Response Posted - 03/16/2009 : 22:59:12

Great I am a CAD Monkey, Design and Construction documents for a good size architect company.

Edited by - Ericson33 on 03/16/2009 22:59:39

shnool
Former Capri-25 Tech Editor

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USA
1032 Posts

Response Posted - 08/15/2012 : 07:23:18

I know this is an old thread, but what did you guys determine, and what was your result?

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klassi1
1st Mate

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88 Posts

Response Posted - 08/15/2012 : 09:02:29

Templated the keel using their templates this summer. Will know more about performance during the Fall series.

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jmadd
1st Mate

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USA
85 Posts

Response Posted - 08/15/2012 : 10:44:00

I never tried anything. A year or so ago Mark H. mentioned he used a custom template and was going to write up a tech article for the Mainsheet but I don't know what happened with that. See http://catalina-capri-25s.org/forum/topic.asp?TOPIC_ID=21919

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shnool
Former Capri-25 Tech Editor

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USA
1032 Posts

Response Posted - 08/15/2012 : 11:56:02

Well, as I said, I have to do a full bottom job on the boat this fall, and as luck would have it I MAY have an indoor place to do it (how cool is that?)... anyway, if I do, I'll have time to do it right, and while I am there it makes sense to me to make sure the keel is A) symmetric, and B) setup for the light airs we have <10knots most of the time. so any input you guys might have would be helpful.

My brother is chomping at the bit to create some NACA foil templates using ACAD and some solid modeling stuff he does, but I figured $180 or so from guys who do this stuff all the time might be as good or better. Then maybe I can guilt the brother into helping me actually do the work.

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joearcht
Navigator

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USA
241 Posts

Response Posted - 08/16/2012 : 05:18:31

Still on my to do list :(. I'm going to die with a BIG to do list I'm afraid.

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shnool
Former Capri-25 Tech Editor

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USA
1032 Posts

Response Posted - 08/16/2012 : 06:36:18

Ok, well here's the deal then. If I wind up doing it, I'll take pictures and let you know my thoughts and post here. Because so much time, money, effort will be put into this project, and because the bottom of my boat has like 30 layers of ablative on it peeling and bubbling in various stages, I think sanding a square keel and doing VC17m would be faster! so don't expect me to go through this, and say it sux, but I'll at least be able to tell if if it was "worth" my time.

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shnool
Former Capri-25 Tech Editor

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USA
1032 Posts

Response Posted - 02/17/2013 : 15:50:40

Alright, I am debating on doing this or not, leaning towards not. Using the min/max measurements for chord lengths from this site, I found my keel to A) be symmetric and B) within the max chord lengths.

I suspect the original owner of the boat did some keel shaping. The boat was measured for MORC racing when it was ordered in 1982 (I'd be curious if anyone has links to early capri MORC race results).

Anyway, if my keels shape is good (chord lengths are)... it'd mean my keel is "slightly fat." If I read correctly a fatter keel provides better upwind performance, but more drag downwind.

Thoughts anyone, does anyone think that doing a compu-keel if I am this close will make much difference?

Edited by - shnool on 02/17/2013 15:51:35

klassi1
1st Mate

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88 Posts

Response Posted - 02/21/2013 : 20:03:00

I used Comp U Keel to reshape my keel last summer. My keel was a bit asymmetrical port vs starboard so this was an opportunity to fix that. It was fairly easy to do. Just raced 6 times after it was templated. I'm reserving judgement on whether it has improved performance until the end of this Springs series.

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shnool
Former Capri-25 Tech Editor

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USA
1032 Posts

Response Posted - 02/22/2013 : 05:01:15

Klassi... please do keep us posted. I just went through and measured mine, found it to be JUST within tolerances as per the association. I found it to be symmetrical... but compukeels seems like a great way to bring everything to optimum. I am almost tempted to buy and see if the shape is right.

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klassi1
1st Mate

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88 Posts

Response Posted - 06/11/2013 : 12:39:18

Reporting back on the performance of a templated keel. We kicked the local J24 hotshot's butt a couple of times. Consistently beat the Merit 25s (3 of them). Good upwind performance and I don't feel like I lost alot going downwind. All in all, I'm happy with how we performed this Spring. Good crew on a good boat giving everybody a run for their money.

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shnool
Former Capri-25 Tech Editor

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USA
1032 Posts

Response Posted - 06/11/2013 : 15:40:09

AWESOME! Beyond cool. Hmmm... now you gots me thinking. Now that my bottom is done, re-fairing the keel is NO BIG DEAL..

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