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Swing keel weight and wobble

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EricCBohn
Deckhand

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USA
5 Posts

Initially Posted - 06/26/2019 : 11:07:40

I have a 1983 Catalina 25.

After hauling it out yesterday to have the keel lifting hardware replaced I noticed a few things that I'm unsure about. Video for reference: https://youtu.be/T--10I63XEE

You'll notice a lot a play in the keel when I grab and rock it. Is this normal, or should I be concerned?

Also, notice the angle of the keel cable as it goes from boat to keel, and notice the cable actually rubbing against the thru hull. The cable is routed aft of the turning ball as required.

Any advice would be appreciated.

Edited by - EricCBohn on 06/27/2019 08:30:42

EricCBohn
Deckhand

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USA
5 Posts

Response Posted - 06/26/2019 : 11:08:41

Also, does anyone know the weight of the swing keel by itself?

islander
Master Marine Consultant

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Response Posted - 06/26/2019 : 11:53:17

1500 LBS

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

GaryB
Master Marine Consultant

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Response Posted - 06/26/2019 : 17:32:04

I don't own a swing keel but from what I've read in the past, the movement of the keel is most likely a result of a worn pivot pin and possibly the pivot pin bushing in the keel itself being worn or the hole wallowed out. Both can be repaired.

Can't answer your question on the cable rubbing.

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GaryB
Andiamo
'89 SR/WK #5862
Kemah,TX

Lee Panza
Captain

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USA
465 Posts

Response Posted - 06/26/2019 : 22:32:34

Eric:

The amount of movement in your video appears to be similar to my '84, which has apparently always lived in salt water. I've never heard of a keel falling off due to pivot wear, but the banging back and forth inside the case is an annoyance, especially when anchoring out overnight.

I've seen pictures of swing keels with the pivot hole extremely worn, and this by itself does not seem to be a huge problem. If the bronze pivot pin is significantly worn that would be a little more worrisome, for the obvious reason that the pin supports that 1,500 lb. hunk of cast iron. But the pivot pin would have to wear quite a bit before it approaches the point of failure, and apparently the cast iron rusts and wears away more rapidly than the bronze.

What does concern me in your video, however, is that the hanger casting on the port side appears to be loose. I'm not sure if I saw movement at around the 13-second mark, because the camera was itself moving, but at the very least it appears that the forward end of that casting has dropped from its correct position. This is clearly evident at about the 15-second mark.

Here's a link to one of the Catalina assembly drawings showing those hangers in detail:

The bottoms of the hangers on my boat are essentially flush with the bottom surface of the hull. Yours appears to be protruding below that surface at its forward end.

As you can see from the assemply drawing, these hangers are supported by 5/16 bolts screwed into receivers embedded in the fiberglass of the hull. They are only engaged in the receivers by about an inch or less, so if this particular bolt has backed-out some (it looks like the hanger has dropped perhaps 1/4" or so) it has lost a significant amount of his holding power.

If this is nothing more than a loose bolt, you should be able to screw it back in where it belongs. There was some discussion on this forum awhile back regarding how much to torque these bolts, but I can't remember now what we came up with. At a minimum I'd recommend taking it out and coating it with Tef-Gel or Lanocote before running it back in and torquing it down firmly.

While you're hauled-out you would be well-advised to replace the pin, the hangers, and the bolts. Catalina Direct sells kits with the components. At the same time, you should also install the spacer discs that keep the keel centered in the case. These are all things a do-it-yourselfer can do (although grinding the new hangers by hand could be tedious). Repairing the worn pivot hole in the keel might be more than you'd want to do yourself - it may be a job for a machine shop if it's worn as much as the video suggests - although people have posted here about having done this themselves as well. You can expect that a bushing will be required, and it will need some of the lost cast iron to be replaced around it.

Leon Sisson put together an excellent description of this work:

http://sailincat.com/boating/C25_proj/C25_sk_idx.htm

Its good that you're planning on replacing the cable; consensus seems to be that it should be done every two years or so. Your video didn't examine the cable, or the attachment to the keel, but cable failure is not rare, and it can have devastating consequences.

You may also find that the turning ball needs replacement if the groove has worn much deeper than it should be. This may well be why the cable seems to be contacting the bronze pipe riser. Sometimes the ball stops turning on its pivot, and the cable wears a deep slot in one side.

None of this is rocket science, but you should probably figure on doing more work than you had intended during this haul-out. You didn't indicate how long you've had your boat, but after 35 years the keel pivot and the keel raising system are overdue for a major overhaul. It's a job I'm intending to finally get to myself this year, having finally retired, but for now this is all I can pass along to you.

The trouble with a destination - any destination, really - is that it interrupts The Journey.

Lee Panza
SR/SK #2134
San Francisco Bay
(Brisbane, CA)

EricCBohn
Deckhand

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Response Posted - 06/27/2019 : 05:22:51

Thanks Lee. We just bought the boat a few weeks ago. It's been in freshwater its whole life. I've read about the "banging" from the swing keel on these boats, but our keel doesn't have an audible bang at least.

This video is of this Tuesday, 6/25, when we had it hauled out to replace the keel lifting hardware (with kit from CatalinaDirect) as the tube the cable rides in was so weathered and cracked it would seep water when squeezed (we didn't replace the pivot hardware, I didn't think I'd need it at the time). While it was out I did't notice any hangar movement as I rocked the keel back and forth. If you slow the video down to 0.25 it doesn't appear to move?

I'm brand new to boats so I'm learning as I go.

Edited by - EricCBohn on 06/27/2019 07:18:18

AlMo
1st Mate

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USA
55 Posts

Response Posted - 06/27/2019 : 17:31:05

I get a distinct humming noise that seems to emanate from the SK cable; is it the tune of a stainless cable against a brass tube? I.e., tubular bells :). And if I have the cable inspected annually, and sail only in fresh water, would you say I can get away with 3+ years of use?

1978 C25 "X Lives" #1035
SR/SK

Lee Panza
Captain

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465 Posts

Response Posted - 06/27/2019 : 19:18:24

Eric: If the rubber riser tube is cracked you HAVE to replace it; no question. Part of it is below the resting waterline, and if it cracks more and begins to leak unnoticed when the boat is unattended in the water... well, you know the rest. But it sounds like you did, and it sounds like you've relaunched.

In addition to replacing the rubber tube (and the turning ball) I would have suggested you check the integrity of the bronze riser pipe, especially its connection to the hull by a mound of resin material. I think people here refer to this as the "volcano" as an apt description. This "to-hull" connection (rather than a proper "through-hull" fitting) has been problematic for some people. There are similar connections at the drains from the sinks and the "ice-melter." Obviously you won't want to check them if you're back in the water, because you wouldn't be very pleased with yourself if you do discover that there's a problem with one of them. Next haul-out.

As for the "keel clunk" you'll notice it when the boat is being tossed around a bit. Normally the keel rests against one side of the case or the other, but when the boat rocks back and forth while the keel wants to remain stationary, you'll hear it. It's sometimes noticeable when you tack or gybe, but it's most disturbing at night.

Speaking of sounds: Alex, you brought up another well-known idiosyncrasy of our swingers. That hum is the cable vibrating back and forth from the water rushing past it. This has to do with the phenomenon that engineers call vortex shedding. You'll notice that the pitch changes as you increase or release tension in the cable. Some people here prefer to keep some tension on the cable while others allow it to go slack. I'm in the latter camp; I suspect that an inaudibly low frequency oscillation is less likely to disturb the metal (even though it may be traveling a little farther back and forth) than a higher frequency vibration while the cable is carrying tension. But I'm not a metallurgist. I need to point out, however, that if you leave much slack on the winch drum the cable will become a sloppy mess. When you go to raise the keel you should guide the cable back to an orderly arrangement of each turn lying neatly next to the one before it; otherwise, successive windings will compress the irregular wraps and could create kinks that weaken the cable. When I was dry-sailing my boat (it lived on the trailer in the yard, even though I was sailing it every other weekend) I found this to be a nuisanse that I just learned to live with; I kept a work glove nearby for this.

Lastly, I'm not going to comment on the frequency of changing the cable in fresh water rather than salt. I'm sure a lot of swinger owners, even on salt water boats, don't religeously change-out the cable. But it's like that old saying: "Even Russian roulette is PERFECTLY SAFE five sixths of the time on the average."

OK, poor analogy; I apologize.

But the thing about crevice corrosion in stainless steel is that it can be happening with little or no superficial evidence. This is the same reason for changing-out the standing rigging periodically. The consensus in the boating world, even beyond our little community here, seems to be 10 years, or more frequently in the tropics.

So Eric, you're off to a good start, and you'll find people on this forum with a lot of experience to share. The rule is: there are no dumb questions except the ones not asked. I'd strongly encourage you to join the Association to help keep this going.

The trouble with a destination - any destination, really - is that it interrupts The Journey.

Lee Panza
SR/SK #2134
San Francisco Bay
(Brisbane, CA)

EricCBohn
Deckhand

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USA
5 Posts

Response Posted - 06/27/2019 : 19:35:27

Thanks again Lee. Yes, it's back in the water.

We're probably going to have the keel removed this winter and do the full refurbish (bored out, new pivot pin machined, new hangars, sandblast and epoxy, etc). Does anyone have an idea on a reasonable price for paying someone to do this work?

Edited by - EricCBohn on 06/27/2019 20:13:51

islander
Master Marine Consultant

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USA
3992 Posts

Response Posted - 06/28/2019 : 07:39:58

quote:
Does anyone have an idea on a reasonable price for paying someone to do this work?

Almost impossible to guess. Different parts of the country have different rates for marine work usually T&M. Also depends on what needs to be done and what unknown problems they may encounter. Preferably you would want someone or a facility who has worked on Catalina swing keels before.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Edited by - islander on 06/28/2019 07:43:20

Frank Law
Navigator

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USA
159 Posts

Response Posted - 07/01/2019 : 21:00:44

The Hole in the keel for the pivot pin does wear. I had a hole that might resemble a comma or peanut and it would clunk when lowered .
With keel dropped / lowered I made the hole as round as I could using hand tools and had a machine shop make a stainless sleeve which I epoxied into the enlarged hole . The sleeve from Catalina direct was
too small in diameter . That seemed to fix my problem at the same time I replaced the hangars and pivot pin which did not look that worn

Frank Law
Ex cat 25 owner

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