Lee helm

SollaSollew · #1 (**permalink**) 10-20-2008

Although a pleasure in a breeze, my boat exhibits significant lee helm when the wind drops off. Below 5 knots the wheel is at 3 o'clock or worse. She rides on a dual keel (this is NOT a bilge keel, if you don't know what it is I can't explain it without a drawing, well I sort of can, imagine two fins in line with one another connected at the bottom by bulb) with 5.5 feet of draft. In these conditions the traveller is pulled to windward all the way. What do list members suggest. I read somewhere that one should reef the genoa to better balance the boat. For what it's worth the boat loves to sail at anchor despite a riding sail and an all chain rode. If the boat has a fault it is this.

Eric

JohnRPollard · #2 (**permalink**) 10-20-2008

Eric,

I understand the keel configuration (Bavaria uses something similar). But I'm having trouble reconciling your description of "lee helm" with your statement that the helm is at "3 o'clock".

Are you saying that, on a starboard tack, you must turn the wheel about 1/4 turn to starboard? And, on a port tack, you must turn the wheel 1/4 turn to port?

Are or you saying the opposite, i.e. that on port tack you must turn the wheel 1/4 turn to starboard, and vice versa?

tenuki · #3 (**permalink**) 10-20-2008

sit on the other side of the tiller..

sailingdog · #4 (**permalink**) 10-21-2008

As for sailing at anchor: Either get a riding sail made up or anchor by the stern. Don Jordan has a very good argument for anchoring by the stern—but many boats don't have the gear necessary to do it.

Lee helm, especially very consistent lee helm as you have on your boat, is often caused by a problem in the rigging—if it isn't a problem with the original design to begin with. It would help if you said WHAT FREAKING BOAT YOU HAVE. Some boats have known issues with severe lee/weather helm and many have known solutions. It could be something as simple as adjusting the mast rake a bit.

Idiens · #5 (**permalink**) 10-21-2008

I think that keel type is called a tandem keel and is used to reduce draft without reducing side force, but I guess it will not have the same righting moment as a deep fin keel that you boat may have been designed for.

Usually excess weather helm can be fixed by trimming the rigging (mast further forward). However, weather helm usually gets worse with increasing wind, so that reefing can help reduce it. It entirely depends on the boat. I often remove the main sail completely before starting to reef the genoa, but that's just my boat.

You also need to look at how much rudder is applied with 90 degrees of helm. I read that more than 17 degrees of rudder is undesirable because of increasing drag.

A lot of boats "hunt" at anchor. Some often recommend anchoring from the stern, or rigging a trip line to tension the rode from the stern. You can also try changing the scope and setting the rudder hard over, which sometimes works in a tideway.

SEMIJim · #6 (**permalink**) 10-21-2008

Quote:

Originally Posted by SollaSollew

Although a pleasure in a breeze, my boat exhibits significant lee helm when the wind drops off. Below 5 knots the wheel is at 3 o'clock or worse.

Does this happen on all points of sail, on both tacks?

Quote:

Originally Posted by SollaSollew

In these conditions the traveller is pulled to windward all the way.

That may or may not be correct. Yes, in light air, on certain points of sail, you may want to induce twist by easing the mainsheet and trimming the traveller to windward, but you almost never want the boom above the boat's center-line.

Quote:

Originally Posted by SollaSollew

What do list members suggest. I read somewhere that one should reef the genoa to better balance the boat.

I think you'd be well-served by getting yourself a copy of Ivar Dedekam's Sail and Rig Tuning.

Quote:

Originally Posted by SollaSollew

For what it's worth the boat loves to sail at anchor despite a riding sail and an all chain rode. If the boat has a fault it is this.

That is not uncommon amongst modern keelboats. Our Pearson 30 does it, and she's about as well-balanced as you could hope for.

Jim

DrB · #7 (**permalink**) 10-21-2008

apparent? I assume you mean apparent wind. If it doesn't, I wouldn't be too concerned.

My boat has "lee" helm in anything less than 3 kts, meaning if I put my helm at a neutral rudder and adjust my genoa and main, after about 20 seconds it will head down wind. Above 5, it has a balanced or weather helm depending on sail trim.

Bringing the boom/traveler toward windward in very light air is not typically done. Traveler mid or down and sail slightly baggy. The idea is to help get the sails to fill with the limited wind that you have. If you want to get rid of lee helm, put weight on the leeward side of the boat towards midship. This helps fill the sails and increases the wetted surface and will decrease "lee" helm.

Throw away the book that you read reef genny to make the boat more balanced in light wind. Reefing reduces sail area, not what you want in light air.

DrB

SEMIJim · #8 (**permalink**) 10-21-2008

Quote:

Originally Posted by DrB

Bringing the boom/traveler toward windward in very light air is not typically done.

True about the boom, most definitely not true about the traveler. It is quite common to have the mainsheet traveler car to windward in light air, to get the boom back where you want it after easing the mainsheet for more mainsail twist.

Jim

tenuki · #9 (**permalink**) 10-21-2008

Quote:

Originally Posted by tenuki

sit on the other side of the tiller..

I was being serious btw...

DrB · #10 (**permalink**) 10-21-2008

Quote:

True about the boom, most definitely not true about the traveler. It is quite common to have the mainsheet traveler car to windward in light air, to get the boom back where you want it after easing the mainsheet for more mainsail twist.

Agree somewhat. Traveler should really be no more than mid or just past mid windward in very light air, which 3kts is. OP said he had it ALL THE WAY windward. In my experience, doing that in light winds means you have really no control on any part of the sail because wind/air pressure flow just isn't there. Bringing the traveler all the way up and then releasing the sheet to drop the boom often yeilds a bouncing boom that causes the sail to go slack then taunt, slack, taunt, etc. I think the better process is to center the traveler and then get weight leeward to generate a fuller sail, get speed/air flow, then fine tune the sail

Also, assuming the boat the the OP is talking about (5.5 draft, doble keel) is a heavy boat and 30+ ft, 3 kts of wind is barely enough to get the thing moving. You really need to get some air flow over the sails before subtle changes in sail shape have an effect.

DrB