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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

Keel cable hum

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Scotd
Navigator

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USA
136 Posts

Initially Posted - 01/27/2004 : 10:34:13

I have not head much on the forum about keel cable hum, does it hum on the Catalina 25, I have owned a Venture 22, a Chrysler 22 and a Mac 26c and all of those had the keel cable hum. In fact it was easy to trim the sails on those boats for the hi pitch of the cable.
Being a new Catalina 25 owner and not even being able to rig the boat til spring (South Dakota winters) or get it in the slip til the ice comes off the lake. Maybe the snow and cold is getting to me, starting to think of these strange things. LOL

Scot Dannenbring
"Getaway"
#3376 1982 SK/SR
Rapid City, SD
http://rap.midco.net/scotd6/

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Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 01/27/2004 : 10:48:00

It sounds like you are an experienced hummer. I just got my boat last september and was surprised by the hum and have mixed feelings about it. It is, as you say, a tuning tool but also an in your face waste of forward motion force. That hum is not free, I know the cable would not be free of drag even without the hum, the hum just reminds you you are being robbed. A cylinder is the worst possible aerodynamic shape, our cables are a large diameter. I wish there were some other material we could use to reduce the size and the drag.

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Gary B.
Admiral

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USA
969 Posts

Response Posted - 01/27/2004 : 11:56:34

The hum is caused by the vibration of a taut cable. Try taking the tension off it by releasing the winch a turn or two. The hum on my boat stops, just as if you released the thumbscrew on a guitar or violin string. I doubt that it has a serious effect on "drag" to do this, so I don't think it would slow you down any, or much.....I stand to be corrected.

Seems to me that the relatively large keel is going to have so much disturbed water behind it already that the drag of the cable would not be significant, whether taut or loose.......Again....please show me where I am astray in my thinking here; I want to learn....

Gary B.
Vice Commodore
Encore! #685 SK/SR

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LeighMarie
Navigator

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USA
188 Posts

Response Posted - 01/27/2004 : 13:11:28

I have had the same experience as Gary. When it starts to hum, a turn or two to loosen the cable takes care of it immediately. The cable is already dragging through the water so it's not like you're adding any more drag other than maybe another half inch or so of cable. And if there is extra drag and it slows you too much, then maybe you have more issues than just with the cable. (Didn't mean to be offensive, Frank!)

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Steve Milby
Past Commodore

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USA
5908 Posts

Response Posted - 01/27/2004 : 13:56:21

If memory serves, the swing keel is rated by the handicappers as a fraction faster than the fixed keel, so the drag caused by the cable must not be too significant.

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Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 01/27/2004 : 14:24:26

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Gary B.
 
Seems to me that the relatively large keel is going to have so much disturbed water behind it already that the drag of the cable would not be significant, whether taut or loose.......Again....please show me where I am astray in my thinking here; I want to learn....
Gary B.
Vice Commodore
Encore! #685 SK/SR
<hr height="1" noshade id="quote"></blockquote id="quote">
Gary,
You have given me piece of mind whether you are right or not, I simply quietly repeat... "It's is turbulated water anyway...OMM". I don't know about you but I feel better already.
Steve,
... and faster yet with out the drag of the cable! DARN! "It's is turbulated water anyway...OMM". AHHH

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ClamBeach
Master Marine Consultant

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3072 Posts

Response Posted - 01/27/2004 : 15:49:29

I'd venture a guess (sailor's pun?) that you get a lot more drag from the water flowing through the keel trunk than the drag the cable itself. Note that the cable drag changes a lot when you sail through rafts of eelgrass and accumulate a couple bales of it around the keel fitting.

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gnorgan
Admiral

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USA
563 Posts

Response Posted - 01/27/2004 : 21:40:10

Hum

What hum?

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 01/27/2004 : 23:33:18

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by ClamBeach
 ...Note that the cable drag changes a lot when you sail through rafts of eelgrass and accumulate a couple bales of it around the keel fitting.<hr height="1" noshade id="quote"></blockquote id="quote">

There's nothing like having to dive over the side and swim under the boat to remove a hundred pound ball of seaweed from the keel cable!

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Scotd
Navigator

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USA
136 Posts

Response Posted - 01/28/2004 : 12:00:03

I did notice that on the other boats that depending on the angle of the keel the boat sailed different. Not always was all the way extended the best for the sailing conditions. Is the Catalina the same way or do you just lower it and forget it? I really noticed this on the Chrysler 22. It made loads of difference if I raised it a foot or so.

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Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 01/28/2004 : 13:20:38

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Scotd
 I did notice that on the other boats that depending on the angle of the keel the boat sailed different. Not always was all the way extended the best for the sailing conditions. Is the Catalina the same way or do you just lower it and forget it? I really noticed this on the Chrysler 22. It made loads of difference if I raised it a foot or so.
<hr height="1" noshade id="quote"></blockquote id="quote">
Great question.
As recent C25 owner with only a few weeks on the water I have wondered the same thing. As the winter has progressed and I have become more intimate with my swing mechanism I have come to the conclusion that the mass of the C25 keel is too great to trifle with and that since the head of the keel "snugs up" in the head trunk and the entire keel is kind of floppy when not fully down and snugged up, that these things should be either fully down or fully up.
That's my take.

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Brooke Willson
Admiral

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USA
983 Posts

Response Posted - 01/28/2004 : 14:54:17

<blockquote id="quote">quote:<hr height="1" noshade id="quote">these things should be either fully down or fully up.
<hr height="1" noshade id="quote"></blockquote id="quote">

Exactly.

Brooke

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Randall
Navigator

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123 Posts

Response Posted - 01/29/2004 : 21:07:23

Scot, I've always assumed the same with my Cat 25: crank the keel up slightly to balance the helm.

My 79 TR/SK is my fifth sailboat, and when I launched her, I followed the conventional wisdom and put a couple of cranks on the winch. I have always been very impressed with the light, well-balanced helm on "Kite". When I first logged onto this website a couple years back, there was a lengthy discussion going on about how to balance the helm, how to build a balanced rudder, etc. I was incredulous! I couldn't figure how you could improve on the design. I had a Spirit 6.5 that was an absolute brute to control in any kind of breeze. In contrast, my Cat is a kitten in a high wind. Could it be that adjusting the keel makes a siignificant difference in helm pressure?

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Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 01/29/2004 : 21:22:27

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Randall
 Scot, I've always assumed the same with my Cat 25: crank the keel up slightly to balance the helm.

My 79 TR/SK is my fifth sailboat, and when I launched her, I followed the conventional wisdom and put a couple of cranks on the winch. I have always been very impressed with the light, well-balanced helm on "Kite". When I first logged onto this website a couple years back, there was a lengthy discussion going on about how to balance the helm, how to build a balanced rudder, etc. I was incredulous! I couldn't figure how you could improve on the design. I had a Spirit 6.5 that was an absolute brute to control in any kind of breeze. In contrast, my Cat is a kitten in a high wind. Could it be that adjusting the keel makes a siignificant difference in helm pressure?
<hr height="1" noshade id="quote"></blockquote id="quote">

Yes yes yes, it will. But at what cost? My concern is that the pin-keel interface is too woobly to be safe over prolonged positioning anywhere other than fully down or fully up. If you need to trim to save your bacon I would do it in a minute, but I would never trim my keel as a normal proceedure, it puts too much strain on things and can wollow out the keel-pin hole.

I had a Spirit 23 and miss it terribly, it was a wonderful boat.

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Randall
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123 Posts

Response Posted - 01/29/2004 : 22:07:28

Our Spirit 6.5 (21' 3") was our first boat 10 years ago. My wife has never forgiven me for selling it. She still considers it the perfect sailboat.

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IndyJim
Navigator

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USA
130 Posts

Response Posted - 01/29/2004 : 23:18:00

I too have been mesmorized by that cable hum. Since I don't race, the cylindrical drag and turbulated water isn't an issue. When I'm not at the helm, its kind of fun to play tunes by adjusting the tension and thus the pitch of the hum. Just kidding.... But for a guy who sails on an inland mud puddle, when she's humming her tune, the boat is really hauling! So, while taking the tension off a little will reduce or eliminate the hum, I like to think of it as RPM's.

Gosh, a whole thread without somebody suggesting we all do wing keel conversions!

Off to Strictly Sail in Chicago! Gotta get that winter "sailing fix". Just 2 1/2 months until I can slide her back in the water!

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