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Swing Keel Cable Failure

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redeye
Master Marine Consultant

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3474 Posts

Response Posted - 12/11/2013 : 08:12:46

<< The cable was the weak link. >>

Wow.. didn't know that .. I would have thought it was the connection .. well it sorta was but it was the cable.

The cable swag, right.

Edited by - on

Merrick
Navigator

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USA
192 Posts

Response Posted - 12/11/2013 : 12:46:40

I am sure every 2 years is conservative even in salt water and CD is erring on the safe side as stated above. However, if in doubt take the conservative way out, so I change mine every two. If it didn't have the potential to sink the boat it would be different. I've wracked my brain about devising a backup system and there have been some interesting threads about this.
Common sense should have told the guy in the letter that after 10-12 years in salt water it might be time to inquire at least.

Edited by - on

ftworthsailor
Captain

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USA
279 Posts

Response Posted - 12/11/2013 : 14:54:40

Wow! That "Swing" keel is HEAVY. Is it really about $1500-1600 pounds? I am going to hoist my boat up to get it off the trailer. Once I do, I would like to drop the keel and move it out of the way so we can work on the hull. How do I move this heavy keel? I was thinking of building some sort of wheel'd chassis to slide it into and then have the ability to move it out of the way for now. None of the wagons or dolly's look heavy enough to do this. What have you used?

R

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9017 Posts

Response Posted - 12/11/2013 : 18:35:42

quote:
Originally posted by ftworthsailor

Wow! That "Swing" keel is HEAVY...

Yup. The specs say 1500#. There's at least one article in the Tech Tips on lowering it using threaded rods. Whatever the method, great caution is called for.

Edited by - on

Dave5041
Former Mainsheet Editor

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USA
3754 Posts

Response Posted - 12/11/2013 : 19:54:15

Redeye: The swage was fine. The cable broke 6-8" above the swage. Actually, the strands broke at different points over a 4" span. Once the repeated shock loads of the keel dropping a couple of feet broke the first strand the progression was probably fairly rapid. A good swage should be stronger than the wire rope in tension; it is wire flexion at the hard points at each end that kill a swaged fitting

Edited by - on

glen
Captain

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359 Posts

Response Posted - 12/12/2013 : 12:23:42

quote:
Originally posted by ftworthsailor

Wow! That "Swing" keel is HEAVY. Is it really about $1500-1600 pounds? I am going to hoist my boat up to get it off the trailer. Once I do, I would like to drop the keel and move it out of the way so we can work on the hull. How do I move this heavy keel? I was thinking of building some sort of wheel'd chassis to slide it into and then have the ability to move it out of the way for now. None of the wagons or dolly's look heavy enough to do this. What have you used?

R

My keel cradle is in use right now, and at a shop (with my keel in it) for the winter, so I have to guess at the dimensions. I had the keel cradle made for me and he used a steel plate as the base (old scrap stuff to save me $). I believe the plate was 3/8” to ½” thick and about 14” by 30” long and wide. Welded to that was 4” by 4” angle iron legs about 20” to 24” high, this creates a slot for the keel to sit between. If you were to turn it over it would look something like a table with open leafs. The distance between the legs is a couple inches wider than the thickness of the keel. They are welded so one of the flat sides of the angle is parallel to the keel, with the other angle set to the outside of the slot. He drilled holes in the top of each leg; one hole on the outside facing angle is there so the shop can hook a chain to it and have a point to lift it with a hoist; it is also where you will secure the cradle to the trailer. The other hole on the angle facing the slot, has a nut welded to the outside edge. This is used for a 3/8 to ½” bolt to thread through, which will tighten against the keel, pinching it at the top part of all four legs. Wooden shims are placed in the slot at the bottom (between keel and legs) to hold the keel from shifting side to side at the base. The base also has roles drilled in it so I can secure it to a transmission jack. This type of jack is nice for aligning the keel during the reinstall. Both the removal and reinstall are done at the marina, with the boat suspended in a hoist. It goes without saying, you need a good trailer, and yes the cradle is HEAVY, but our marina has equipment that will handle it. Hope this is helpful

Edited by - on

BCG-Woodbury
Mainsheet Editor

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USA
396 Posts

Response Posted - 12/12/2013 : 20:58:42

Chuck -

Thanks for the input. As the Editor or the C25/C250/Capri 25 Catalina Owners Association I think I owe it to readers re-post the letter that CD sent. I received the letter as I'm sure many CD customers did. I'll contact CD tomorrow and find out any legalities of re-posting their letter. It might not make it into the next issue but just getting it out there is surely better than not, in my honest opinion.

Regards,

Brian Gleissner

Edited by - on

redeye
Master Marine Consultant

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3474 Posts

Response Posted - 12/13/2013 : 05:38:56

<< The cable broke 6-8" above the swage >>

Wow.. OK I did not know that.. thank you.

Edited by - on

pastmember
Master Marine Consultant

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2402 Posts

Response Posted - 12/13/2013 : 09:47:57

Would that be at the ball?

Edited by - on

RAG Sailor
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USA
144 Posts

Response Posted - 12/13/2013 : 15:03:53

Thanks for the heads up. As many of you know I just took over the RAG Sail II in September. The (on the hard) survey said the cable looked fine. She's kept in lake water so I have that on my side. However, even before reading up on all of the swing keel comments I thought best to leave the keel in the down position (even at her slip). It's only logical that if the pivot fails the keel would fall straight down as opposed to swinging down with a thud if the cable broke! The cable was last replaced in 2011 so I intend to change it out in the new year and at the same time make the modifications to tighten up the pivot point with the kit from CD.

Speaking of CD, I've registered with the site but have not bought anything as of yet. It is in my profile that RSII is a swing keel but I have not received any info on the cable failure maintenance. So I believe whomever said that they are sending the notice only to past purchasers is correct.

Since RSII is in a remote lake area, there is really only one place to bring her to do the cable replacement and pivot modification. They've never done one before but I am sure they are capable of doing it. It would be most helpful if anyone has a complete set of photos to post of the job they did so I can give that to them as well. I know that the kits come with illustrations but photos are always better.

This forum has been the best source and I rely on it more than any other.

Thanks and Happy Holidays to all your Catalina Skippers!

Edited by - on

Dave5041
Former Mainsheet Editor

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3754 Posts

Response Posted - 12/15/2013 : 11:34:42

Frank, that was on my Clipper, so no ball. The keel retracted fully into a high trunk with a turning block on top to lead the cable straight back to the winch. I would think that the ball could be a stress point for likely failure.

Edited by - on

bbarstow
Deckhand

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USA
16 Posts

Response Posted - 12/16/2013 : 13:36:33

I bought my C25 swing keel three years ago. (1979 - #1223). I will, of course replace the cable using CD's $123 kit when she is hauled this spring. I sometimes keep the keel retracted for the following reasons: 1. When the keel is extended (when my slip is sufficiently deep) I can hear (feel?) the keel moving from side to side due to currents, and I find this to be a tad disconcerting. 2. The slip is often too shallow to permit full extension. 4. While under way in light breezes, speed is higher with the keel partially or fully retracted. Am I making serious errors in thinking? And is this behavior dangerous? When I bought the boat, the first thing I did was search the web for information about when to extend/retract. Guess that was before I joined the Association. Your responses) will be greatly appreciated.

Edited by - on

RAG Sailor
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144 Posts

Response Posted - 12/16/2013 : 13:57:37

quote:
Originally posted by bbarstow

I bought my C25 swing keel three years ago. (1979 - #1223). I will, of course replace the cable using CD's $123 kit when she is hauled this spring. I sometimes keep the keel retracted for the following reasons: 1. When the keel is extended (when my slip is sufficiently deep) I can hear (feel?) the keel moving from side to side due to currents, and I find this to be a tad disconcerting. 2. The slip is often too shallow to permit full extension. 4. While under way in light breezes, speed is higher with the keel partially or fully retracted. Am I making serious errors in thinking? And is this behavior dangerous? When I bought the boat, the first thing I did was search the web for information about when to extend/retract. Guess that was before I joined the Association. Your responses) will be greatly appreciated.

You no doubtedly read this and other threads about the keel being retracted full time and the possibility of it falling due to the cable snapping. So, I won't go into that. My keel is always extended but I have never heard the sound you and others have mentioned. I'm in a sheltered marina on a dammed-up river lake so I might not have the same current issues others have. However, owning an '81, I'm sure time has taken its toll and I do intend to do the pivot modification this spring. In case you have not seen this, take a look at this: http://www.catalinadirect.com/index.cfm?fuseaction=feature.display&feature_id=46 Once you complete this first page, go to the bottom and click on next story. I believe doing the pivot update and keeping my cable refreshed every 2-3 years will let RSII to keep on sailing a long time.

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9017 Posts

Response Posted - 12/16/2013 : 15:24:24

quote:
Originally posted by bbarstow

...4. While under way in light breezes, speed is higher with the keel partially or fully retracted. Am I making serious errors in thinking? And is this behavior dangerous? When I bought the boat, the first thing I did was search the web for information about when to extend/retract...

You may have found discussions about centerboard and daggerboard boats raising their boards when sailing downwind. If the keel retracts substantially or fully into a trunk, this can reduce drag. The C-25 keel remains mostly exposed, so drag won't be reduced to the same degree. However, stability will. Most centerboards provide virtually no ballast (except enough to keep them down). Your keel, in the down position, provides the righting moment the designer wanted. Partially raised, it still should. Fully raised while sailing to windward, you're not using the boat as intended, so you could risk a negligence charge if something happens. (Somebody reported here they could not measure a speed advantage--I didn't have a swinger, so can't comment.)

Partially raising the keel also moves the "center of lateral resistance" (CLR) aft, which could induce lee helm, where the boat is trying to turn downwind rather than up. This is a safety issue--a small amount of weather helm is desirable, so that if you let go of the tiller, the boat points up and stops. With lee helm, if you let go, the boat turns downwind, jibes, backwinds the jib, jibes again,...

(Correspondingly, C-250 WB owners have found partially raising the centerboard reduces weather helm from excessive to reasonable.)

Edited by - Stinkpotter on 12/16/2013 15:32:04

Dave5041
Former Mainsheet Editor

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3754 Posts

Response Posted - 12/16/2013 : 18:23:10

I couldn't demonstrate a speed improvement in light winds. I expected a modest gain, but it wasn't there. The reduced righting moment was there, as was greater directional stability or sluggish helm, depending on how you perceive it. I suspect that the minimal reduction of wetted surface is offset by the slot induced turbulence acting on the longer chord of a retracted keel and the flat leading edge. Much of the keel's mass is in the lower third, so raising it causes a disproportionate loss of righting. Very little of there retracted keel is out of the water flow, so lift, or lateral resistance, is not significantly changed when the boat is upright in light wind.

Edited by - on

Steve Milby
Past Commodore

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USA
5851 Posts

Response Posted - 12/16/2013 : 19:32:26

The proponents of raising the keel downwind point to the flatness of the leading edge of the keel as a source of drag, which they think slows the boat. But, the leading edge of the keel isn't flat. It's rounded, much like the leading edge of the wing of a Cessna airplane. Like an airplane wing, the leading edge of the keel is an integral part of the foil design, and it's shaped to divert the water to either side of the keel smoothly, without creating turbulence, and with a minimal amount of drag. Moreover, the keel is swept back at the leading edge, which also greatly increases the angle of attack and, consequently, reduces drag as the water flows over it. I think the idea that the keel's leading edge causes drag is overrated to the point of being almost insignificant. I think the amount of the keel's wetted surface is a far more significant factor.

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Stinkpotter
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Djibouti
9017 Posts

Response Posted - 12/16/2013 : 19:58:49

I think Dave was referring to the "flat leading edge" presented when the keel is raised--in other words, the top of the casting rather than the shaped edge along its length. The wetted surface doesn't change much, because most of the C-25 keel remains exposed when raised. It seems he's suggesting that the shape of the top offsets somewhat the reduced length of the forward edge.

Interestingly (maybe or maybe not), the more contemporary NACA foil design does not include a tapered leading edge--it has a fairly fat, rounded leading edge and a finer, tapered trailing edge. This is illustrated by a comparison of the original C-25 rudder with its sharp leading edge, and the NACA foil, balanced one they introduced in about 1988 (and that I bought as a replacement). Apparently, this reduces turbulence in some way I don't understand... and turbulence is one of the main contributors to drag and detractors from lift. I studied some fluid dynamics once, but it was probably long before that NACA design work.

Edited by - Stinkpotter on 12/16/2013 20:02:37

Steve Milby
Past Commodore

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USA
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Response Posted - 12/16/2013 : 20:39:33

I wasn't responding to Dave's comment. His reference to a "flat leading edge" reminded me of the theory that is often raised by others that the leading edge of the keel is a significant source of drag, and that it is reduced by retracting the keel. I have been pondering that theory for awhile, and it finally occurred to me that the reason why the leading edge of the keel isn't a significant source of drag is because the designer gave it a foil shape that is specifically calculated to reduce drag to a minimum. The keel isn't just a fat slab of cast iron. It's a foil. If it was just a fat slab of iron, then it might be a significant source of drag.

Edited by - Steve Milby on 12/16/2013 20:41:42

RAG Sailor
Navigator

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144 Posts

Response Posted - 12/16/2013 : 21:31:56

Skippers:
This is all great dialog but at the risk of alienating you all, can we please stay on topic? This thread was about swing keel cable failure. Some of you have gone off on a tangent. Many of us subscribe to certain topics because they hold our interest. It's disappointing to get an alert about your topic of interest only to read it has nothing to do with it. Again, please forgive me but I really think it's in all of our best interests.

Edited by - on

Stinkpotter
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Djibouti
9017 Posts

Response Posted - 12/16/2013 : 22:05:00

Edited by - on

Steve Milby
Past Commodore

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5851 Posts

Response Posted - 12/17/2013 : 06:11:22

quote:
Originally posted by RAG Sailor

Skippers:
This is all great dialog but at the risk of alienating you all, can we please stay on topic? This thread was about swing keel cable failure. Some of you have gone off on a tangent. Many of us subscribe to certain topics because they hold our interest. It's disappointing to get an alert about your topic of interest only to read it has nothing to do with it. Again, please forgive me but I really think it's in all of our best interests.

What more would you like us to say about swing keel cable failure? It appears that we have discussed the subject as comprehensively as necessary. If we have missed something, you can probably do a search and find it in one of our many earlier discussions of the subject.

We don't have a rule on this forum that strictly limits us to discussing a narrow subject. After you have been a member here for awhile, you'll find that we generally adhere fairly closely to the topic of the discussion until we have covered the subject comprehensively. Then, we sometimes let the thread wander wherever our interests take us. Each of us comes here for our own reasons and with our own expectations. You apparently prefer discussions that rigidly adhere to the original subject. I prefer more freewheeling discussions. I think it's important that we address those original issues first, but after doing so, I enjoy sorting out what I like to think of as the "mysteries" of sailing. Those mysteries are the things that often come up in our discussions, for which nobody seems to have a clear answer. At age 71, I'll be the first to admit that I don't have all the answers. There's alot that I still don't understand about the art of sailing, but I love searching for the answers. The forum doesn't exist only to serve your interests. It serves the interests of each of us.

Forum members come and go. New members tend to ask the same basic questions that others have asked in the past, and those of us who have been around for awhile don't find it very stimulating to cut and paste the same answers to the same questions that we addressed many times in the past. In this thread, I figured out something that I didn't understand before, and I find that exciting. I don't want you to be disappointed when you click on a thread and find some discussion that isn't narrowly limited to the original topic, but I trust you can be patient while some of us pursue our interests, as well as yours. In time, you might find it as exciting as we do to learn something new about the art of sailing.

Edited by - Steve Milby on 12/17/2013 06:14:27

bbarstow
Deckhand

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USA
16 Posts

Response Posted - 12/17/2013 : 10:00:59

I would also like to respond to 'Rag Sailor'. I am the guilty party who originally strayed from the straight and narrow of the swing keel cable topic. All of your responses have been of great benefit - especially if you consider that my thinking was flawed to the point that I sometimes sailed with my keel retracted. That behavior was dangerous, and will not be repeated. For all your input I am grateful, and I thank all who responded.

Edited by - on

pastmember
Master Marine Consultant

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2402 Posts

Response Posted - 12/17/2013 : 13:43:10

When will we get a "like" button on this forum? I "like" Steve Milby. BBarstow... its all good. RAG, hang in there, we are worth it.

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ftworthsailor
Captain

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USA
279 Posts

Response Posted - 12/17/2013 : 14:27:10

While I can understand RAG's concerns and annoyances, I am also of the mindset that the discussions need to have more character associated to the response. Such as real life examples, pictures and even sidebar discussions that occur as a result of multiple responses to a single issue that may or may not be controversial.

In all cases, I prefer that a response be from someone that takes the time to provide us with a genuine response or a cut and paste of a prior response that applies. This Forum would get old quickly if every question was answered with "go SEARCH for the answer because it has already been addressed somewhere in a past article or response".

"Active member" answers are always of more interest (to me). Not to take away from any of the posting of the past, because there are numerous postings that provide links to published articles, YouTube videos, and websites - each adding to your overall learning process. It's how we grow as a community.

I am not really looking forward to having to drop my keel after the cold weather passes in order to do the repairs to my boat, however the urge to have this boat floating and working again is strong. Without your suggestions and pictures, I doubt I would be able to accomplish this task. The costs associated with taking it to a Marine Repair facility would be prohibitive, which is probably why the insurance company Salvaged her in the first place. Costs more than the boat is worth on the market.

I guess you just gotta love the Catalina 25 to want to save one and NOT allow one of them to go to the scrapyard and get cut up.

To everyone that responds to any posting, Much Thanks.

Edited by - ftworthsailor on 12/17/2013 14:30:25

ftworthsailor
Captain

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USA
279 Posts

Response Posted - 12/17/2013 : 14:35:02

RAG said:"So now, if y'all think I should walk the plank, well, so be it..."

No..... Actually, I think you need to drink another bottle of RUM ! ! ! Aaaaarrrgghhhhhh!!!

Edited by - ftworthsailor on 12/17/2013 14:36:59

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