Swing keel on a 42-50 footer

[wmac]

C&C made some nice sailing boats with swing keels and if you've got the bucks you would have a tough time doing better than one of Ted Hood's "Little Harbors"

[Adrian Chen]

Originally Posted by Username25

- The keel is only fully up or fully down. Sailing only with the keel in fully down position.
- Loss of inside space due to keel box.
- Running aground auto-releases the keel.
- Longer keel = more powerful rig, maybe.

Southerly yachts will sail with the keel in any position. Leeway will increase as the keel is raised.
Inside space is affected more on smaller versions of Southerly but the layout usualy works well

[Montanan]

Quote: The statement that the retraction of a swing keel doesn’t affect stability is utter nonsense. This is just not possible. End Quote.

Much depends on whether the swing keel is heavily weighted so as to provide for greater lever arm, e.g., made of steel, or whether it is intended to primarily be a lifting foil for aiding in pointing and reducing leeway, in which case the lifting keel may be quite lightweight, e.g. made of expanded foam and the vessels stabilizing weight thence resides in the shoal keel and not in the swing portion of the keel.

I have seen both kinds of swing keels. Since a swing keel is mounted on an athwartship axle / pin, it typically does not have as much weight as say a bulbed keel with a lead filled bulb, or a canting keel which has its axle bearing running down the centerline of the hull.

Many boats receive a lot of their stability from their hull shape and less from their keel weight or location. I have no need for placing my swing keel down unless the boat is being powered over by strong winds when sailing on a beam or reach, in which case I typically feel the need to reef and ease the sails to provide stability, or I will feel the need to lower the swing keel to reduce roll speed or magnitude due to rough surface conditions. The boat typically performs better [faster and less heeled] with the swing keel partly up and the sails reefed than to have the swing keel all the way down and the sails not reefed. There being considerably less drag with the keel not down and the center of lateral resistance is shifted aft as well as the center of gravity shifted aft such that weather helm is lessened dramatically when dealing with strong winds. One can't shift the vessels weight trim when dealing with fixed keel boats. Unless one has operated swing keels you just don't get a sense of how significant weight redistribution and foil repositioning has on a vessel.

Growth can occur in the bury portion of the swing keel and one has to remove the hard growth, barnacles else the swing keel can be come difficult to raise. Vegetative growth is not much of factor inside the bury as it is not in the water stream slowing the vessels hull.

[real_goat]

Originally Posted by Montanan

Much depends on whether the swing keel is heavily weighted so as to provide for greater lever arm, e.g., made of steel, or whether it is intended to primarily be a lifting foil for aiding in pointing and reducing leeway, in which case the lifting keel may be quite lightweight, e.g. made of expanded foam and the vessels stabilizing weight thence resides in the shoal keel and not in the swing portion of the keel.

I have always thought that the difference between a swing keel and a centreboard is that one is ballasted (most of the time in the end) and the other one is not or only lightly.

If it's only used for pointing and reducing leeway I would classify it as a centreboard, If it's used for stability as a swing keel.

[tinger]

Check out Seaward Yachts, they make a 46'.... a little out of my budget though.

[Montanan]

Originally Posted by real_goat

I have always thought that the difference between a swing keel and a centreboard is that one is ballasted (most of the time in the end) and the other one is not or only lightly.

If it's only used for pointing and reducing leeway I would classify it as a centreboard, If it's used for stability as a swing keel.

Real Goat you raise an interesting nuance in nautical semantics as to there being a distinction in terminology regarding the placement or inclusion of ballast on a pivoting keel. On dinghy monohull sailboats much of the ballasting is from railmeat, with modern monohulled keelboats ballasting is achieved from the addition of countering weight in the bottom of the boat, the question being where exactly are the heavier bits located.

From wikipedia, there being many other potential reference choices, likely with different takes on the subjects: "A centreboard or centerboard (US) is a retractable keel which pivots out of a slot in the hull of a sailboat, known as a centreboard trunk (UK) or centerboard case (US). The retractability allows the centreboard to be raised to operate in shallow waters, to move the centre of lateral resistance (offsetting changes to the sailplan that move the centre of effort aft), to reduce drag when the full area of the centreboard is not needed, or when removing the boat from the water, as when trailering. A centreboard which consists of just a pivoting metal plate is called a centerplate. A daggerboard is similar but slides vertically rather than pivoting.

The analog in a scow is a bilgeboard: these are fitted in pairs and used one at a time.

Lt. John Schank (c. 1740 – 6 February 1823) was an officer of the British Royal Navy and is credited with the invention of the centerboard. Schank, however, gave credit for the idea to British Brigadier General Earl Percy."

"Centerboards are often ballasted in keelboats." As to modern keelboats they are "technically any sailboat with a keel—as opposed to a centerboard or daggerboard."

Definition of keel: the longitudinal structure along the centerline at the bottom of a vessel's hull, on which the rest of the hull is built, in some vessels extended downward as a blade or ridge to increase stability.

Then there are the hybrid boat bottoms, wherein a boat that has a ballasted shoal keel that can perform well without a lot of added lever arm of moveable ballasting of its swing keel. The difficulties of a heavy swing keel is that it takes a lot of effort to raise is back into its trunk and there is a challenge in supporting its root at the pivoting attachment point. The hybrid boats have a fixed keel and a swing keel. The swing portion being additive to the shoal portion of the ballasting, either significantly additive or moderately additive to the total ballast leverage. The boats with a swing keel inside a shoal keel blend between a boat with a deep higher aspect ratio keel and a long low aspect ratio keel. The blending of both advantages and disadvantages, but with the ability to raise said narrow higher aspect ration, [heavily ballasted or lightly ballasted] portion of the keels. Note: Keels being plural, one inside the other.

Canting keels are a form of pivoting keel that pivots athwartship instead of along the centerline, hence are not centerboards / centreboards. Canting keels do not typically raise into the hull but rather are limited to side to side rotation, albeit there are truly complex raising / canting appendages.

[tweitz]

I have had a Beneteau 323 with lifting keel for 13 years. Because of my dock location, which requires passing a sandbar, the shallow draft of the lifting keel in the up position (2'11") gives me tremendous flexibility. The keel retracts into a trunk which is at the center of the dining table and is totally unobtrusive in the cabin. I have had very little maintenance due the lifting keel, and I have never heard the keel "clunking" either at anchor or underway. As a beamy boat, I suspect a lot of the stability comes from the form, rather than the weight, and I often sail with the keel up. I do have noticeably more leeway with the keel up, and I have always wondered about the effect on heeling with the keel up or down on a beam reach, considering that the keel down lowers the center of lateral resistance dramatically, while the keel up would allow more sideslip through the water. Clearly at the extreme the keel down would be more effective, so in stronger winds I do lower the keel all the way (7' draft). That being said, a deep fixed keel would undoubtedly provide more righting moment. I have rarely struck anything with the keel down, but when i did, the keel just swung back and there was no damage to the keel or the hull. We have twin rudders, each offset from vertical, and as a consequence we have never come close to a broach. The boat is incredibly stable in following a course, so much so that several times I thought I was on autopilot and only after a while noticed that the autopilot was on standby, the boat was simply tracking by itself. Our only real disadvantage is that we raise and lower the keel with a manual winch, 100 turns up or down. That can be a bit strenuous, and requires me to be down below a little longer than i would like when single handing. Overall, in places where there is benefit to being able to enter shallow waters, I believe the benefits vastly outweigh the disadvantages, which are often recited and in my experience overstated. I would buy a lifting keel again in a minute.

[Medved]

Originally Posted by tweitz

I have had a Beneteau 323 with lifting keel for 13 years. Because of my dock location, which requires passing a sandbar, the shallow draft of the lifting keel in the up position (2'11") gives me tremendous flexibility. The keel retracts into a trunk which is at the center of the dining table and is totally unobtrusive in the cabin. I have had very little maintenance due the lifting keel, and I have never heard the keel "clunking" either at anchor or underway. As a beamy boat, I suspect a lot of the stability comes from the form, rather than the weight, and I often sail with the keel up. I do have noticeably more leeway with the keel up, and I have always wondered about the effect on heeling with the keel up or down on a beam reach, considering that the keel down lowers the center of lateral resistance dramatically, while the keel up would allow more sideslip through the water. Clearly at the extreme the keel down would be more effective, so in stronger winds I do lower the keel all the way (7' draft). That being said, a deep fixed keel would undoubtedly provide more righting moment. I have rarely struck anything with the keel down, but when i did, the keel just swung back and there was no damage to the keel or the hull. We have twin rudders, each offset from vertical, and as a consequence we have never come close to a broach. The boat is incredibly stable in following a course, so much so that several times I thought I was on autopilot and only after a while noticed that the autopilot was on standby, the boat was simply tracking by itself. Our only real disadvantage is that we raise and lower the keel with a manual winch, 100 turns up or down. That can be a bit strenuous, and requires me to be down below a little longer than i would like when single handing. Overall, in places where there is benefit to being able to enter shallow waters, I believe the benefits vastly outweigh the disadvantages, which are often recited and in my experience overstated. I would buy a lifting keel again in a minute.

This is great feedback, as much as I would love to own a Southerly, it was a bit out of my budget, so i have been looking at Bene and Jeanneau who offer this feature. The trick is going to be finding a used boat with it, since it is not that wide spread.

[jeepers]

Have you considered the Grampian 46 twin swing keel. The molds are available in Canada.(A huge savings with the current exchange rate) A twin swing keel ketch rigged with possibly dual inboards is my choice.

Grampian 46 History
https://sailboatdata.com/sailboat/grampian-46

[wingssail]

A lot of east coat raceboats used a shallow draft keel with a retractable centerboard. This is not as good for potential groundings but otherwise gives you some more choices.

[boatman61]

You could always build yourself a Waterwitch with lee boards.. no trunk in cabin, easy to maintain and you can beach/dry out..

[boatman61]

Originally Posted by tweitz

I have had a Beneteau 323 with lifting keel for 13 years. Because of my dock location, which requires passing a sandbar, the shallow draft of the lifting keel in the up position (2'11") gives me tremendous flexibility. The keel retracts into a trunk which is at the center of the dining table and is totally unobtrusive in the cabin. I have had very little maintenance due the lifting keel, and I have never heard the keel "clunking" either at anchor or underway. As a beamy boat, I suspect a lot of the stability comes from the form, rather than the weight, and I often sail with the keel up. I do have noticeably more leeway with the keel up, and I have always wondered about the effect on heeling with the keel up or down on a beam reach, considering that the keel down lowers the center of lateral resistance dramatically, while the keel up would allow more sideslip through the water. Clearly at the extreme the keel down would be more effective, so in stronger winds I do lower the keel all the way (7' draft). That being said, a deep fixed keel would undoubtedly provide more righting moment. I have rarely struck anything with the keel down, but when i did, the keel just swung back and there was no damage to the keel or the hull. We have twin rudders, each offset from vertical, and as a consequence we have never come close to a broach. The boat is incredibly stable in following a course, so much so that several times I thought I was on autopilot and only after a while noticed that the autopilot was on standby, the boat was simply tracking by itself. Our only real disadvantage is that we raise and lower the keel with a manual winch, 100 turns up or down. That can be a bit strenuous, and requires me to be down below a little longer than i would like when single handing. Overall, in places where there is benefit to being able to enter shallow waters, I believe the benefits vastly outweigh the disadvantages, which are often recited and in my experience overstated. I would buy a lifting keel again in a minute.

Delivered one of these UK to the Algarve.. sailed like a witch downwind with keel up.. only bad moment was when the owner decided to drop the keel unannounced at 6kts.. luckily only small seas else we would have broached for sure.. did I ever give him a bollocking.
Unlike a Southerly they cannot be beached.
This was the same owner who thought it amusing to suddenly release then lock 6ft of snuffed spinnaker uphaul as I was upfront pulling it down with a F6 and increasing wind.. boy did my coccyx hurt when I landed.

[Fore and Aft]

Boatman61 have you ever sailed any Maurice Griffiths bilge Keelers?
Cheers

[Andina Marie]

We had a retractable keel on our 71 ft steel ketch. Draft down 13 feet, draft up 5.5 feet. Perfect for cruising the Bahamas. It was actually about 8 inches off center so with it UP there was a contiguous keel of about 5" the full length of the boat for riding smoothly over rocks and trees.

[boatman61]

Originally Posted by Fore and Aft

Boatman61 have you ever sailed any Maurice Griffiths bilge Keelers?
Cheers

Did have one of these many moons ago but for me it was more a long shallow keel with bilge plates than a true bilge keeler..
https://sailboatdata.com/sailboat/eventide-24
Not a bad little boat, not fast but did all I asked of her.