• Mobile App For Android Now Online!

    Download it here. The app is searchable in the Google Play Store under Sailboat Owners.

    Sorry iPhone/iPad users, we are still waiting on Apple. :(

    Click the X in the upper right corner to make this go away

Swing keel effectiveness

Tsam

.
Jun 28, 2011
30
S2 6.8 Long Lake, MN
On my 6.8m S2 I have a shoal draft keel(2ft) and a swing keel/centerboard that extends 2.5ft below fixed keel. I have not been able to notice a performance difference with the swing keel retracted or extended. So, I don't use it much. When should I notice the greatest effect of having it extended?
Thanks
 
Jan 19, 2010
8,921
Hunter 26 Charleston
When beating (pointing) high into the wind. Try this. With your keel in the up position, see how far into the wind you can sail before you sails start to luff. Then right at the point of luffing lower your keel and see if you can sail a few degrees higher. You should and if not, something is not tunned correctly.
 
Jan 19, 2010
8,921
Hunter 26 Charleston
As a corallary, one advantage to a swing keel is that on a broad reach or running, you can raise the keel to reduce drag and pick up a little speed.
 
Sep 22, 2018
1,646
Hunter 216 Kingston
On my 6.8m S2 I have a shoal draft keel(2ft) and a swing keel/centerboard that extends 2.5ft below fixed keel. I have not been able to notice a performance difference with the swing keel retracted or extended. So, I don't use it much. When should I notice the greatest effect of having it extended?
Thanks
How sure are you that the swing keel actually moves ? ;)
 

WayneH

.
Jan 22, 2008
799
Tartan 37 Pensacola Shipyard, FL
My Tartan has a keel/centerboard arrangement. Beating to windward with the centerboard up causes her to side slip and greatly increases the pressure on the rudder to keep her straight. Lowering the centerboard allows the helmsman to center the rudder and not have to fight it at all.

Raising the centerboard allows us to get into our slip. :biggrin:
 

LloydB

.
Jan 15, 2006
485
Macgregor 22 Silverton
How do you measure your performance now? If by course over ground or speed thru water you will probably not notice a 10% difference in a 15 minute run halfway across the lake. 13 miles instead of 12 is a bunch when in a two hour race.
 
Sep 24, 2018
1,045
O'Day 25 Chicago
@rgranger is right about pointing ability. I have a shoal keel with a swing centerboard as well. It was stuck up for the first few weeks on the water. Then magically pointing ability seemed to improve. It took a couple of weeks for me to be convinced that it dropped down. I didn't dare try to pull it up for fear that it might get stuck again. When I pulled it up at the end of the season is when I knew 110% that it had dropped down. I think @rgranger 's test is an excellent idea and I hope it gives instant feedback
 
Nov 8, 2010
11,240
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
When beating (pointing) high into the wind. Try this. With your keel in the up position, see how far into the wind you can sail before you sails start to luff. Then right at the point of luffing lower your keel and see if you can sail a few degrees higher. You should and if not, something is not tunned correctly.
This will not tell much.

Regardless of what configuration of keel, the sail trim is what it is (a function of sail shape and sheeting angle). A keel will prevent SIDESLIP and generate lift, which over the course of an upwind leg will add up. But you really cannot see it at a single point of time.
 
Jun 14, 2010
1,432
Quorning Dragonfly 1200 home
Lowering the keel should also help improve slow speed turn response to produce a tighter turn radius, and reduce leeway when docking.
 
  • Like
Likes: SailingLoto

TomY

Alden Forum Moderator
Jun 22, 2004
2,428
Alden 38' Challenger yawl Rockport Harbor
I think people mistake a centerboard for something that will snap your neck when you lower it, like a Turbo-charger or something.

All the centerboard can do is provide added lift. 'Lift' helps a sailboat go to windward. You don't 'feel' it sailing to windward. At it's best, the added lift simply improves the boats actual course to windward, over the ground. Nothing changes on deck, the boat or the sails angle(s).

That's why many people say, "I never see any change so just leave the centerboard up" There is nothing to see an not much to feel.

I can often see the result of the additional 4' of lowered centerboard by an increase in the angle to the wind the boat will make to windward, on the GPS chartplotter. This is revealed in the heading into the wind narrowing by a few degrees, or the icons pointer on the screen swinging a few degrees closer to the wind. Nothing else on deck changes, this is simply the lift working to increase course to windward.

I'm happy to see 5 degrees improvement to windward, but with all the factors involved (current, wind, wave action and on and on,...) in practice it's often less.