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Go Back   SailNet Community > General Interest > General Discussion (sailing related) > SWING KEELS GOOD or BAD?
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Thread: SWING KEELS GOOD or BAD? Reply to Thread
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Topic Review (Newest First)
02-02-2013 10:26 AM
Smier
Re: SWING KEELS GOOD or BAD?

All very good points, BUT they almost all fall into what I would classify as human error. All but "failure mode 3" are easily prevented or remedied with a little prior planning. The majority of cable/pin/trunk issues arise from lack of maintenance. Yes, it is more work, but in my case for instance, I can't have a full keel boat if I want to sail on our families lake in Ontario. In late summer the water level in our bay has dropped as low as 2 feet at the dock. We can't even launch a full keel sailboat at the boat launch. Properly maintained, many of these have lasted decades with out an issue. I am planning on replacing my keel pin, brackets, and cable this year. My boat just turned 30 years old, and I plan to venture out into more challenging waters soon, so I want to ensure everything is perfect working order. For me it's a small price to pay to be able to sail where I want to! The other huge plus is I can easily take my boat and my family anywhere I get the urge to sail. So in my opinion, swing keels are great, but it really comes down to what your needs are. I see a full keel sailboat, and see it as limiting to my sailing adventures...
02-01-2013 09:07 PM
Harborless
Re: SWING KEELS GOOD or BAD?

Quote:
Originally Posted by CarbonSink62 View Post
IMHO fewer moving parts underwater is better; when I was looking for a Catalina 25, I didn't even look at the swing keel models.

Failure mode 1: the cable breaks while the keel is down and you are stuck in deep water.

Failure mode 2: the cable breaks while the keel is up and the keel (1900#) swings down until it hits the stop (which might not). This could let the green monster into the people tank.

Failure mode 3: The boat surfs down (or falls off) a wave and the keel retracts a bit; at the bottom of the wave, the boat stops but the keel keeps going. See #2 above.

Centerboards aren't as problematic, but I still prefer a solid keel.
Dont forget Failure mode 4, my particular case actually: You leave the board down at dock thinking 1/4 from shore is deep enough. Low tide buries your stick in the mud. Boaters who cant read or dont care zoom by creating big wake. Lateral forces break your wedged centerboard in half.
I have a brand new centerboard- Not by choice.
02-01-2013 04:23 PM
mstern
Re: SWING KEELS GOOD or BAD?

There is a lot of good advice here, but also a lot of sloppy jargon. Swing keels, centerboards and daggerboards are three (very) different things. They have one trait in common- the ability to vary the draft of the boat - but they each implement that trait differently and with different trade-offs.

The keel on a sailboat contains the primary ballast for the boat. With a Swing Keel, that keel (not surprisingly) swings. The arrangement differs boat to boat, but the basics are that a cable lead to the trailing edge of the swinging keel hauls the keel up and down (via a winch of some kind), while the trailing top edge of the keel is affixed to the hull with a single pivot point. While retracted, some swing keels are contained completely outside the hull; some retract into a recess either partially or wholly within the hull. Either way, movement of the swing keel significantly changes the boat's center of gravity and resulting stability. Well known examples of swing keel boats are the Catalina 22 and 25.

A centerboard boat is much like a swing keel boat with one big difference: the centerboard does not contribute significantly to the boat's stability. It contains no ballast. The Oday line of trailer sailers (22, 23, 25) embody this design concept. As one of the posters above noted, the ballast for these types of boats is in the boat itself, encapsulated in the hull in a stubby keel. The centerboard pivots in and out of a slot within this keel. Because its not very heavy, the tackle needed to move a centerboard is much less complicated and easier to maintain than its swing keel cousin. Lots of dinghys that have no ballast beyond the weight of the crew also have centerboards.

A daggerboard is a completely different animal altogether. Daggerboards are unweighted fins that move directly up and down through the bottom of the hull. They can be as simple as the arrangement on a Sunfish, where the daggerboard has a handle on top of it that you simply grasp and pull (or push) to move the board to its desired depth. As you can guess, daggerboards are far more common on smaller dinghy type boats.

One more type of moveable keel is the "retractable keel", that has elements of both the daggerboard (moves straight up and down) and the swing keel (contains the boat's ballast). On the RK series of boats from Seaward, the daggerboards have lead bulbs on the bottom containing the ballast for the boat. Of course, Seaward has devised an ingenious power system to extend or retract the keels/daggerboard as needed. Lets you get into the shallows, but still have a high aspect keel with the ballast down as low as you would have on a fixed keel.

I have an Oday 23, and find the keel/centerboard combination to be the best compromise for me. I get the convenience of variable draft, virtually no maintenance of the mechanism, and the comfort of knowing that the ballast for my boat is encased within the hull and ain't falling off.
02-01-2013 02:15 PM
Lou452
Re: SWING KEELS GOOD or BAD?

I think swing keels good or bad is misleading. The use is what makes the keel good. one type of keel is not a bad thing. Dingy bad / blue water boat good ? The swing keel will let you take that type of boat places and do things others will not go to or do as easy possibly not at all. I like my catalina-22 swing keel and I think for most of my use fresh water lakes it fits better than the other two options. I do not know sales and resale longevety but my opinion is the swing keel catalina-22 is more in demand in this environment than the other two. I see more swing keels in my area. Good Day, Lou
02-01-2013 01:51 PM
ABH3 Boyer
Re: SWING KEELS GOOD or BAD?

I love my swing keel boat. I dont have worries about it failing and swinging down uncontrollably because it is always down when I'm underway. When I hit a random boulder in 8 feet of water it swung up and didnt wreck anything. just took off some paint. My draft with keel up is 2ft 6in and 5ft 6in when down. That puts the weight right where it needs to be so it performs very well in strong wind and bigger waves. I can also trailer my boat easily. As far as the moving that much weight around, I installed an electric wench where the old hand cranker was so all I have to do is press a button. I also keep an extra wench and battery on board just in case. The wench gets used to raise and lower my mast so I can do it single handed. I dont think I would beach it but I can get close enough to shore to walk in without getting my shorts wet. A huge advantage is not having to depend on someone else and have to pay them to pull it out of the water. If there is a big storm on its way or I just want to give her a proper bath hook up the trailer and pull her out. I always dream of a bigger boat but 26 ft is definately big enough for my family and a few friends. It also fits my finances well.
02-01-2013 01:02 PM
Barquito
Re: SWING KEELS GOOD or BAD?

I had trouble in my sailing area, in that, I harvested a lot of weeds on the swing keel cable.
02-01-2013 10:14 AM
jimgo
Re: SWING KEELS GOOD or BAD?

By the way, if the O'Day's 2'10" draft is accurate, it's only 2" deeper than the Catalina 25. There are also wing keel models that don't need a lot of water. They sort of split the difference between swing and fin keels. They are fixed, but shallow draft (the Catalina 25 with a wing is something like 2'11"). Their pointing ability is better than the swing keel models with the board up, but not as good as a fin keel. But, they don't have any lifting mechanisms to worry about.
02-01-2013 10:13 AM
denverd0n
Re: SWING KEELS GOOD or BAD?

Living and sailing around Florida, where shallow water and shifting sand banks are an issue, I think a swing keel is a wonderful thing. That's why I used to have a San Juan 23, which has essentially the same arrangement as the O'Day 25.

Find an unexpected sand bar? The swing keel just pivots up and the boat gently comes to a stop. Pull the keel up the rest of the way and back off or sail away. Easy peasy. With a centerboard it would hit the sand hard and stop suddenly, possibly even doing some damage. If you were heeled over when it hit, then the centerboard is now digging into the sand and holding the boat heeled over. If there isn't any damage, then you pull up the centerboard (with some difficulty if you were heeled when it hit) and go on your way.

Yes, the swing keel includes a pivot point and pennant arrangement that adds a bit of complication. Still, in the 8 years that I owned the San Juan, I never had even one single problem with that. I do not consider it a significant issue, and feel the benefits of a swing keel well outweigh the minor drawbacks. In fact the sailing dinghy that I own now has a swing keel, and I specifically looked for that versus the more common dagger board in boats that size.
02-01-2013 10:06 AM
jimgo
Re: SWING KEELS GOOD or BAD?

I'm new to all this, but I enjoy learning, so when I bought my Catalina 25 I started reading up on this a bit. I'm not an expert, but the following is my understanding. Like Ward said, each form of movable keel has its advantage and disadvantage. A swing keel, like on the Catalina 25, carries a good bit of the balast of the boat in the part that swings. In the Catalina 25, that's something like 1200 or 1500 lbs of balast that hangs down. When the keel is down, you move 1500 lbs (or some portion thereof) up to 5 feet from the boat. This significantly improves the boat's righting motion, and gives her characteristics more similar to a fin keel. Don't get me wrong, I'm not saying that it's "just like" a fin, but the boat tends to behave more like a fin than a shallow draft full keel. The down side is that you have to raise and lower 1500 lbs. And, if the winch, cable, turning ball, swage fittings, pivot bolt, or other part of the lifting mechanism breaks, you have 1200/1500 lbs of steel that will come crashing down and smack into the keel trunk, which in many cases results in the boat sinking, or at least rapidly taking on water. It is rare to see this happen, but it is an important to know about and monitor this as a failure mode.

With boats like the O'Day, you have a very light weight centerboard that swings. 65 lbs crashing into the keel trunk is going to do a lot less damage than 1200-1500 lbs. Of course, the down side is that the balast is moved much higher up in the boat compared to a fin or swing keel. If you think back to high school physics classes where you talked about leverage, moving the ballast closer to the center of rotation/center of gravity on the boat means it takes more balast to counteract the rotational forces imposed by the sails - that is, you need more balast to improve the boat's righting ability if you're not going to put the weight on a long fin keel. The swing centerboard still improves the boat's pointing ability, so it isn't a useless part of the boat, and the mechanisms to control the centerboard are simpler and eaiser to inspect and maintain.

Some boats use dagger boards. Though you typically see these on smaller boats like Sunfish, there are some very large boats that use these. The problem with a dagger is that it won't "kick up" when you run aground, where the swing keel and swing centerboard will do that.

Hope this helps!
01-31-2013 10:49 PM
Waltthesalt
Re: SWING KEELS GOOD or BAD?

There are three things here:
Swing keel: Outside the hull, no centerboard trunk in cabin, heavy and gets the weight lower that the others, draft when up is the width of the keel. Very common on trailersailers like Catalina 22.
Centerboard: Weighs less, not significant in stability, has nothing below hull when it's up, easier to trailer launch and can go into shallow water. Common on dinghys and smaller boats also sharpie type boats. Trunk in the cabin takes space, trunk can be fouled with stones when beaching.
Keel centerboard: Has keel like stability, shallower than a full keel, draft is usually greater than a swing keel. No CB trunk. More common in the larger trailersailers like Catalina 25.
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