Swing Keels

[Wandering Star]

I’m curious and need a sailing lesson. When sailing any design of centreboard dinghy, according to point of sail and wind strength etc, the crew adjust the centreboard for optimum performance allied to stability. When you sail a large cruiser with a swing keel, such as a Southerly, do you sail with the keel fully up or fully down or optimise the angle it’s raised to suit the conditions?

 

[mjcoon]

I've never sailed a yacht with a movable keel. But I do remember that my mother thought that the centreboard on my dinghy contributed to its stability. I had to point out that it was made of wood and so had the opposite effect to having a keel!

 

[Strikeliner]

I’m curious and need a sailing lesson. When sailing any design of centreboard dinghy, according to point of sail and wind strength etc, the crew adjust the centreboard for optimum performance allied to stability. When you sail a large cruiser with a swing keel, such as a Southerly, do you sail with the keel fully up or fully down or optimise the angle it’s raised to suit the conditions?

When sailing the keel is down and it stays down.

 

[SteveA]

When sailing the keel is down and it stays down.

When we had a Bene 21.7 it was the same it stay down while sailing. Very different to a dinghy as the weight moved aft if lifted - just what you don't want.

 

[LiftyK]

Not quite what you asked but let me add that Seal and Parker liftkeel owners actively adjust depth of keel according to conditions. As the keel rises and falls close to vertical, the angle does not change.

 

[kof]

A centreboard is not for stability but for grip and reducing leeway - it's the crew weight that provides the stability. In a Southerly the keel provides both and when sailing its always (far as I know) in the down position to provide the maximum righting force on the boat.

I’m curious and need a sailing lesson. When sailing any design of centreboard dinghy, according to point of sail and wind strength etc, the crew adjust the centreboard for optimum performance allied to stability. When you sail a large cruiser with a swing keel, such as a Southerly, do you sail with the keel fully up or fully down or optimise the angle it’s raised to suit the conditions?

 

[Wandering Star]

Thanks for the replies, consensus seems to be keel down when sailing & up when parked.

 

[Rappey]

I had a iron swing keel.. I certainly had it up when running downwind as that allowed the boat to go faster..
A friend of mine does similar in his jeaneau 33

 

[Bathdave]

As a southerly owner (and former windsurfer racer who used raceborads with retracting dagger boards) I have some experience of this

I have experimented with different keel positions on the boat, and pretty much always now just leave the keel fully down (except when navigating shallow water and harbour sills - and believe me we use the keel switch a lot! )

In a dead run the boat sails fine with no keel, (other than it does tend to roll more - hardly surprising ) and get a little bit more speed, but as soon as you are on a very broad reach you seem to get too much leeway

I have tried partially retracted on broad reaches and no seen no significant speed increase

If we raced it, I might have spent more time trying to eke out an extra .1 and experimenting but it doesn’t seem to make much difference.

The difference with a board is massive, but it think it’s because a board is planing and the grip /lateral resistance is coming from the rails (the edges )

I just love the flexibility the swing keel gives me in the tidal waters round the CI and Normandy/Brittany

 

[Daverw]

When I raced dinghys we would lift the centre board up to reduce drag and get onto plane, but at the same time move weight, stability was then sometimes rather challenging though. Not options on our yacht, certainly would not want to stand on centre board holding on main sheet to right after capsize ?
we have a Kelt 29 with fully lifting keel and the only time it comes up is when beaching or on the hard standing, occasionally when we catch the mud in the Humber but normally power out with the keel lifting its self slightly.

 

[JumbleDuck]

My little Hunter 490 goes faster downwind with the keel up, but it's a faff to lift it and it makes her much wobblier (sorry, "tender") so I usually just leave it down. Unless I am rowing (no engine) when lifting the keel is definitely worth the bother.

 

[TernVI]

I have sailed a Sonata 7 lift keeler. These have the centre-board type iron lift keel housed in a slotted iron stub keel.
So with the keel 'up' draft is about 2ft and with it down about 4ft6?
With the spinnaker up, raising the keel about 1/3 moves the clr back and reduces the tendency to broach, without changing stability much. You want the crew sat to weather and sail the thing flat anyway. Lifting it further on a run is possible.

 

[TernVI]

I've never sailed a yacht with a movable keel. But I do remember that my mother thought that the centreboard on my dinghy contributed to its stability. I had to point out that it was made of wood and so had the opposite effect to having a keel!

Your mother was right!
Well sort of. Many dinghies are very tippy with the plate well up.
Although it doesn't weigh anything, it does a lot to stop the boat heeling quickly.
A boat like a Merlin that's narrow on the waterline can be quite nervy with the plate right up and the boat going slowly!

 

[mjcoon]

Your mother was right!
Well sort of. Many dinghies are very tippy with the plate well up.
Although it doesn't weigh anything, it does a lot to stop the boat heeling quickly.
A boat like a Merlin that's narrow on the waterline can be quite nervy with the plate right up and the boat going slowly!

Thanks for the defence of my late mother. However I think you are just as wrong as she was, with less justification. (I studied physics and she didn't!)

 

[TernVI]

Thanks for the defence of my late mother. However I think you are just as wrong as she was, with less justification. (I studied physics and she didn't!)

I too studied physics and learned to observe....

 

[tyce]

Beneteau 343 swing keel- Keel up when wind on the beam or aft of. 1/2 down approaching a beat and fully down beating. It has a ballast stub so does not need the keel down but when it is it changes draught from 1.3 - 2.6mtr.

I think it makes a big difference when sailed this way.

 

[greeny]

Beneteau 343 swing keel- Keel up when wind on the beam or aft of. 1/2 down approaching a beat and fully down beating. It has a ballast stub so does not need the keel down but when it is it changes draught from 1.3 - 2.6mtr.

I think it makes a big difference when sailed this way.

Agree completely, Beneteau 323 also lift keel (swing) I sail mine pretty much the same as you. Makes a noticeable difference to speed off the wind. Plus the advantage of 0.8 keel up, 1.8 with it down means you can cut corners a bit and can get into places much earlier than others on rising tide.

 

[Barbican]

Having had a couple of Southerly yachts I sail the boat with the keel down as far as the depth of water allows, unless I am going downwind when I find that removing some of the drag from the keel and lifting the bow a little, as the weight transfers aft, helps performance - normally I leave a little bit poking out but I’m not sure if that makes any difference. When motoring I will also often raise the keel in the same manner, to remove the drag, but when manoeuvring in tight confines I will have the keel as far down as possible to ensure the boat has a keel to pivot on which helps control especially going astern. Later Southerly yachts have a couple of big rudders and a skeg aft which maintain directional stability well when the keel is up. The boats remain Category A with the keel up but leeway goes up, and they will heal a little bit more. I do find the keel helps dampen some of the motion if it’s a bit rolly, so yes - in different conditions and taking crew instructions into account the keel will be set accordingly.

 

[ProDave]

My previous boat had a swing keel. It always remained down for sailing except when entering or exiting the harbour near to low water when we needed all the draft we could get. the keel was fully up in the harbour to dry out at low tide.

When our keel was up on that boat there was nothing not even a stub, so steering even under motor was poor, so we always tried to leave a bit of keel down for that reason.

 

[Hermit]

I think it significantly depends if the yacht has a lifting keel or a centreboard. A centreboard yacht (think Ovni, Garcia 45) has all the ballast in the hull and the centreboard is to prevent leeway. Centre of gravity does not move when the board is up. I believe Ovni recommend board up when running before bad weather and Pete goos certianly talks about lifting his board when running.

A lifting keel, however, contains the ballast for the boat. By lifting it, the CogG rises and the boat will become more tender. As such, it should always be down when sailing.