jamesmalcolm

How to make J/24 Keel Templates

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My J/24 is sitting on the trailer, the weather is decently warm, and I have a few weeks off of school for the holidays. I am looking to fair the keel. How do I make a set of templates? I know that the minimum dimensions are in the Class Rules, but I don't know what to do with them. What should I make the templates from? Should I make them in halves? How do I measure to see if the keel is centered in the boat? Does anyone have a photo of their templates? I'm not trying to take anybody's design, I just want to see what I am about to try to make. Any info anyone has would be great.

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Yes, a template that hooks the nose is a good idea to get the leading edge radius correct.  

Mylar is dimensionally stable (mostly) so using that as the source material to cut out the templates is a good idea.  Cut close to the line, then hand sand the last little bit.

 

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New question, can I alter/move around the keel stub? If my keel is off center am I allowed to change the location of the stub if I keep it's shape? 

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My J24 days are well passed and I am sure others are much more knowledgeable, but I do know you want the keel as far forward as possible.  In the rules there is a max measurement from the transom to the trailing edge of the keel and you want that to be at max. 

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Go find the J/24 Facebook groups. One of the class measurers, Tonja, is very active there and will happily answer any questions regarding class legal modifications.

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First, download and read a copy of the class rules.  Don't get rule interpretations off of this forum.

Then, follow the link to the West Systems manual.  Start at page 88, read until end.  Any composite concepts you're not familiar with, start from page 1.  Note that this is information . . . which is not a substitute for experience and skill.

https://www.westsystem.com/wp-content/uploads/Fiberglass-Manual-2015.pdf

A J24 is an asymmetric egg; this process is difficult on a boat that is well built, much less a boat like the 24.  And you don't want the class minimums for a keel shape (I promise, just don't), which means you'll want to pull a shape off another J24 you trust to be a fast and consistent relative to the more competitive fleets in the country.

If I were to buy another random J24 today, the first thing I would look for is a recently optimized keel shape and position from a reputable shop.  If the keel was rubbish, everything else about the boat would have to be perfect before I would buy it, and then I'd save the money to pay a pro to build a keel.  It's such an important component of the boats potential performance and market value.

Good luck!

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It has been thirty five years since I made my set.

I had never done a keel shaping job on any boat.  I did make a few thousand rudders and centerboards fir dinghies and catamarans and I had raced sailboats for about 27 years so I had some general concepts in my mind. 

a guy asked me if I could shape his j-24 keel for him. He said the class ruies showed some minimum thicknesses and described limits on location 

I read the rules 

i laid out the class offsets on some appropriate material, tinkered a bit with the design, cut out some templates and started making keels shaped like those templates. 
 

I still use the same templates.
 

why don’t you think about how you plan to shape the keel, Buy all the materials and tools, secure a place to do the work, and make a templated keel?

as far as I can tell, nobody on the  planet makes Keels as fast as mine, I started knowing nothing and finished a week later, and  there is more advice in this thread than I ever got..

Ask around or read various threads in these forums. People  all over the planet seem eager to point out my total lack of intelligence or sense. You cannot possibly be more stupid and ignorant than I am. 
just build the templates the right way and fair the thing the right way.

it won’t sail as fast as one of mine but if that concerned you, you wouldn’t consider having anybody but me fair the keel 

 

...

...

.. 

..

that was fun
 

 

 

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23 hours ago, Gouvernail said:

It has been thirty five years since I made my set.

I had never done a keel shaping job on any boat.  I did make a few thousand rudders and centerboards fir dinghies and catamarans and I had raced sailboats for about 27 years so I had some general concepts in my mind. 

a guy asked me if I could shape his j-24 keel for him. He said the class ruies showed some minimum thicknesses and described limits on location 

I read the rules 

i laid out the class offsets on some appropriate material, tinkered a bit with the design, cut out some templates and started making keels shaped like those templates. 
 

I still use the same templates.
 

why don’t you think about how you plan to shape the keel, Buy all the materials and tools, secure a place to do the work, and make a templated keel?

as far as I can tell, nobody on the  planet makes Keels as fast as mine, I started knowing nothing and finished a week later, and  there is more advice in this thread than I ever got..

Ask around or read various threads in these forums. People  all over the planet seem eager to point out my total lack of intelligence or sense. You cannot possibly be more stupid and ignorant than I am. 
just build the templates the right way and fair the thing the right way.

it won’t sail as fast as one of mine but if that concerned you, you wouldn’t consider having anybody but me fair the keel 

 

...

...

.. 

..

that was fun
 

 

 

If I could afford to have this done professionally I would. That being an obstacle, I'm doing it myself. I have only been in the class for two years and I have never even seen a set of templates. I've only been able to find one photo online and it was from a Ranger 22. How does one go about lifting a fast shape from another boat? Is it getting a large set of calipers and measuring the thickness at different points of the keel or is it reverse fairing a piece of aluminum to match the keel? I am thinking it is the former but with this class ya never know...

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37 minutes ago, jamesmalcolm said:

If I could afford to have this done professionally I would. That being an obstacle, I'm doing it myself. I have only been in the class for two years and I have never even seen a set of templates. I've only been able to find one photo online and it was from a Ranger 22. How does one go about lifting a fast shape from another boat? Is it getting a large set of calipers and measuring the thickness at different points of the keel or is it reverse fairing a piece of aluminum to match the keel? I am thinking it is the former but with this class ya never know...

You are ahead of where I was two weeks before finishing my first J-24 keel... I have never attempted to copy an existing keel. I cannot answer your question. 
 

really... it is super easy. Make a set of templates that are the right shape and work on the keel until it is the same shape as your templates. 
 

  

 

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