New Replacement Swing Keels; A Group Project

[CloudDiver]

You guys have to know by now that I'm crazy... like coo-coo for cocoa puffs right? I guess I just like a challenge, and I can't resist any opportunity to wield my TIG and Plasma Torches.

So there have been many threads and several dozen comments about getting a replacement for C22 swing keels. Seems like the only plausible 3 solutions are;
1. Restore your keel, no matter how bad it looks... it COULD be saved.
2. Find a used keel at a boneyard that is in better shape than yours, then restore it.
3. Open your wallet and bend over, $2.3K plus freight for a new factory replacement.

So this got me thinking, with all the DIY expertise we have as a group; Why can't we come up with a better solution that replaces most of the high cost with sweat equity?

So looking at the original factory drawing got steam coming out of my ears. I could use 10 gauge cold rolled steel (or even stainless if I want to go bat sh!t crazy) and plasma cut all the shapes I need to do a skin over rib style frame, like an aircraft wing. I would weld in the stainless keel pin bushing as well as 1/2" 13 TPI stainless threaded bung for the cable eye bolt. The profile would be accomplished by rolling the steel skin through a roller to give it a light curve and clamping it down over the rib frame to tack weld, then essentially there would be one weld bead all the way round the edges. The lowest part of the keel would essentially have internal compartments that could be filled with lead and plugged off. Then, just clean up with coarse sanding and paint with Interprotect 2000, light fairing as needed.

I'd need feedback and some help from the group. I don't have a factory drawing which details a profile view of the foil. All I have is my own keel, lol! I'm not too savy with computer drawing tools, maybe someone here is? I think if we put our heads together we can figure this out, keep costs to a minimum, and do a kick ass job!

To get the juices flowing here is the factory keel drawing;

 

[Jacomo Sailor]

I saw somewhere just the other day a profiling template for grinding your keel into a more efficient shape. I was pretty sure it was through Catalina Direct but I just looked and couldn't find it. I did however find a site where you can order complete templates and they do have the C22

http://www.computerkeels.com/c.htm

 

[CloudDiver]

I saw somewhere just the other day a profiling template for grinding your keel into a more efficient shape. I was pretty sure it was through Catalina Direct but I just looked and couldn't find it. I did however find a site where you can order complete templates and they do have the C22

http://www.computerkeels.com/c.htm

Good resource to keep in the back pocket, although I'd rather not pay $60 for something a member here may be able to do. Let's see how it goes.

 

[CloudDiver]

Check this place out... Don't you wish you had one of there in your town? This a sort of creator/builder club where you pay a membership to use heavy equipment. Use the Google walk-through feature to tour the shop spaces and see the CNC Plasma Cutter in the back!

http://makerplace.com/

If someone could lay out the design on a dwg file I could cut the whole thing out of 2 sheets of steel in just a couple hours, maybe less!

 

[Jacomo Sailor]

That place is really cool. I'd go broke building stuff if there was one in my town.

 

[piedpiperIII]

Luke, I did buy the video from catalina direct to watch how to referb my keel and in the packet was a template for the correct foil shape. is that what you are looking for? I did check my keel once it was stripped and down to bare metal, the shape was just about spot on for my keel.

 

[$tingy Sailor]

There's nothing magical about the CD template. It's a 19% NACA foil shape that, when applied perpendicular to the keel, results in a 13% NACA foil shape when water flows over it. The keel hangs at 60 degrees to the hull, 30 degrees from vertical, NOT 45 degrees as stated in the CD package and widely assumed. The info and plots for the shape are available online, for example, here:

http://airfoiltools.com/airfoil/naca4digit

 

[piedpiperIII]

sorry stingy

 

[$tingy Sailor]

For what? No offense taken here. Just tossing in my 2 cents from what I've learned refinishing my keel. There's a lot of misinformation about the design. I'm just trying to set the record a little straighter.

 

[allen-deckard]

Personally if I were to design my own keel to replace my swing keel then I would wave my magic wand and try this out.

I would have basically the same shape as the current keel but would make it nearly solid lead with a stainless hanger extending the length for strength.

The lead would be closer to 800lbs but in the process would not have the keel swing down any longer but would basically be mounted in the swung up position. The added 300lbs should be enough I'd say to keep the boat upright and would eliminate me cranking the keel up and down and eliminate rust corrosion.

Like to add that I don't race my boat nor do I have any future intentions of doing so, so any rules to that effect would have no barring on me.

But alas my days of being a welder/fabricator are over and If I get to the point of replacing my keel I'll have to just buy one of the factory replacements.

 

[Jacomo Sailor]

The lead would be closer to 800lbs but in the process would not have the keel swing down any longer but would basically be mounted in the swung up position.

Can't speak for the C22 since I haven't sailed mine yet, but on my Clipper Marine, if I cranked the keel part way up it greatly changed the balance of the boat and created a pretty strong degree of weather helm. If I cranked it most of the way up I got a lot of lee way. I would expect that the C22 preforms similarly with the keel up.

I'm thinking that a hollow fiberglass keel filled with lead would be the shiz-nit. Basically would be laid up in two half molds with a stainless internal back bone. The upper part would be solid fiberglass and the hollow part would be filled through a hole with lead shot and epoxy and then the hole permanently plugged.

 

[CloudDiver]

The method I am suggesting would actually be overall lighter than the original, but I have no way of estimating by how much. The lead would only be contained in the lower chambers of the internal structure. As Allen pointed out lead is denser than cast iron, so having the mass at the lowest point would give you the correct righting moment but the denser lead would have you use less of it overall.
I would construct the keel overall and then get the finished weight of the steel alone. Depending on how many ribs there are internally and how close they are spaced together I would have a certain number of chambers at the lowest part of the keel, where it is wider of course. I would use the steel keel as the smelting pot itself, heating it up to 700 F with a big propane torch. I'd fill the voids from a 3/4" hole at the trailing edge with lead shot and smelt into the void. After each void I would know how much lead I was able to get into each void and know my total weight.
Lets say the Keel structure weights just 125 lbs when complete without lead. If I have 3 chambers below in the lowest third of the keel and I get an average of 75 pounds of lead into each one I end up with a gross weight of 350 pounds, 225 being lead below 2/3 of the overall length. I think that is about 'ball park' that would give you equal to or better righting moment than the original keel. There are guys over at the boat design forum that could figure this out mathematically and give a better answer.
Anyway, just using my artistic background I could get pretty close drawing out the foil profile with measurements taken off my own keel and cutting out with jigs using my plasma cutter. But if someone has a knack with any CAD software that will save in .dwg format I could cut out all the pieces on the CNC making this a relatively easy process. The fab hours would be reduced by more than 60%.

 

[CloudDiver]

Jacomo, this is actually a great suggestion. Its good because using lead shot with epoxy does not require smelting the lead. Cons, you'd have to make a mold of an original keel first. You'd need lots of room in an indoor shop and it could be quite messy. Between making the mold itself, laying up the new keel, and putting in the shot/epoxy ballast I think you have way more investment in labor and material. Big advantage though, way less steel and potential for rust.

Can't speak for the C22 since I haven't sailed mine yet, but on my Clipper Marine, if I cranked the keel part way up it greatly changed the balance of the boat and created a pretty strong degree of weather helm. If I cranked it most of the way up I got a lot of lee way. I would expect that the C22 preforms similarly with the keel up.

I'm thinking that a hollow fiberglass keel filled with lead would be the shiz-nit. Basically would be laid up in two half molds with a stainless internal back bone. The upper part would be solid fiberglass and the hollow part would be filled through a hole with lead shot and epoxy and then the hole permanently plugged.

 

[CaptDon01]

Personally if I were to design my own keel to replace my swing keel then I would wave my magic wand and try this out.

I would have basically the same shape as the current keel but would make it nearly solid lead with a stainless hanger extending the length for strength.

The lead would be closer to 800lbs but in the process would not have the keel swing down any longer but would basically be mounted in the swung up position. The added 300lbs should be enough I'd say to keep the boat upright and would eliminate me cranking the keel up and down and eliminate rust corrosion.

Like to add that I don't race my boat nor do I have any future intentions of doing so, so any rules to that effect would have no barring on me.

But alas my days of being a welder/fabricator are over and If I get to the point of replacing my keel I'll have to just buy one of the factory replacements.

That's pretty much the Catalina factory new C-22 swing keel that came out in 1995 with the introduction of the MK-II version. I understand that because it uses lead for the ballast, the lead is only in the lower section of the keel, and the keel is 50 pounds lighter, but actually has a higher righting factor, and it will keep your boat class legal. It's a plug and play improvement for the boat that we still plan to do with our 1988 New Design C-22.

The Catalina factory uses a lead shot and resin mixture for the ballast on the Catalina-18. The fixed shoal draft keel is molded as part of the hull, and is filled with 450 pounds of lead shot. Great little boat with nice performance, absolutely unsinkable,(think Boston-Whaler construction), and one has sailed factory stock from Oxnard CA to Hawaii several years ago, (did have a Raymarine autopilot).

Little known fact, the factory also had a wing keel conversion kit for the swing keel version C-22, (like they made for the C-25's). I spoke with the factory and they are not sure where the mold is since the big move out of Woodland Hills to Largo Florida.

Don

 

[Jacomo Sailor]

I've read about that wing keel conversion in the past. Seems converted boats suffered from poor performance and didn't point well. It would still be a fun project to tackle though and if kits were still available I could see myself doing it. Maybe a guy should design a bolt on conversion that is a full blown fin keel.

 

[allen-deckard]

Never knew or never looked I should say that they are located in largo florida.

Heck that's an afternoon's drive for me guess if I ever decide to get a keel from them I could save some $'s on shipping anyway.

Wonder if they'd stick it on for me as well

 

[CaptDon01]

Yeah, years ago when they bought Morgan Yachts. 2012 they closed the Woodland Hills factory and moved everything to Largo,(more room and lno more hassles from California). They told me 4-6 week delivery for a new swing keel.

Don

 

[CloudDiver]

I wish I could get my hands on drawings for that wing keel conversion, I bet I could pull it off. I imagine it would be possible to add additional weldments (the same as the 5/16 bolts for the keel hangers) than would allow it to be a bolt in piece, and be able to switch back to the swing keel.

 

[ShotgunSlim]

Never knew or never looked I should say that they are located in largo florida.

Heck that's an afternoon's drive for me guess if I ever decide to get a keel from them I could save some $'s on shipping anyway.

Wonder if they'd stick it on for me as well

I have family in the area and stayed around while visiting them one Wednesday afternoon so I could get the factory tour. Do it!! Well worth the time to see the place and Mr. Warren Pandy gave a great tour of the facility. Unfortunately, rain cut the outside part of it short so I'd like to go back one day.

 

[CaptDon01]

One of the drawings for the C-22 and C-25 wing keel retrofit kit.

Don