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-   -   Weather Helm: Desirable or Dangerous (http://www.sailnet.com/forums/seamanship-navigation/83370-weather-helm-desirable-dangerous.html)

sea_hunter 02-01-2012 01:46 PM

Weather Helm: Desirable or Dangerous
 
While weather helm has an effect on many boats, some say that they like a little bit,others say "no way". Weather helm can act as a "dead man's" switch where if you fell overboard the boat would head into the wind and stall, or it can take your boat into a crazy dive windward that strains the steering , your arms and your nerves. Having less weather helm allows your boat to self steer, balanced between the load on the sail(s) and rudder~keel. Is there a balance between too much and too little weather helm and is there a time when it's dangerous rather than desirable.

sailingfool 02-01-2012 02:29 PM

I dont see material helm pressure (weather or lee) as ever desireable, as you will be losing boat speed in correcting it. Minor weather helm can be a plus in that it contributes to some helm feel upwind and makes staying in the groove easier.

A big question about the significance of weather helm is whether you are steering with a tiller or a wheel. A plus of a wheel is that it provides some leverage in dealing with weather helm, and permits no-stretching steering while sitting on the comfortable weather side. With a tiller, weather helm can be a killer on the back and shoulders, as 10-20 minutes of two hands pulling the tiller to your belly leads to asking someone else to drive...

Faster 02-01-2012 02:36 PM

I think your poll is missing a response, along the lines of "normal 5 degrees or so, easily held" which would be, I believe, a common response.

On our boat (frac, big main small jib) the amount of weather helm varies greatly with point of sail. Close to beam reaching in a breeze can load up pretty good whereas on the wind it's just about right.

I do think it's preferable to lee helm...

jackdale 02-01-2012 02:44 PM

Of course, DDW there is feel at all to the helm. That is why I do not like to run wing on wing. I agree with sailingfool's reasoning, give me a touch of weather helm. Like faster I think another option would desirable.

pdqaltair 02-01-2012 03:30 PM

Other factors:
 
a. Sail selection. Did you reef the jib first, or both together?
b. Are the sails blown-out? Has the point of maximum draft moved aft?
c. Trim. All sorts of possibilities.
d. There is a difference between helm feel and helm angle. 2-4 degrees of helm angle generally helps a boat get to weather by providing lift. For this reason (and others) lee helm is always bad; it drags you to leeward. However, feel is also very much about rudder balance;how does the shaft location relate to the COE on the blade? I've had boats with adjustable rake and I would always adjust for a light, finger tip feel. Personal preference.
e. Speed. On many high performance boats the helm goes light as the boat accelerates, if everything is trimmed correctly. This is generally over 10 knots and is a result of increased water flow.
f. Course. Some boats will have strong helm if close-hauled, very little beam reaching, and more broad reaching. Some of this is speed, some of this is COE sail location vs COE foil location (changes when the sails are eased).

So, it is many things, even on one boat.

One problem with heavy helm is what happens if the rudder ventilates in fast running; A boat with helm--either way--will be uncontrollable and will broach fast. Something to think about when going fast deep. If you're pushing hard, aim for reasonable neutral helm.

QuickMick 02-01-2012 04:04 PM

The sail condition as mentioed above is (imho) huge. my buddy put new halsey canvas on and it erased it. then I promptly preformed an accidental gybe (with no time for ye ole 'gybe ho') while no one was knocked in the head or mob who know how much of a load i dropped on his brand new canvas!! :eek: I dont see how it could be desireable as you are just adding drag via rudder.

pdqaltair 02-01-2012 06:05 PM

Quote:

Originally Posted by QuickMick (Post 825157)
I dont see how it could be desireable as you are just adding drag via rudder.

Good point. Very boat dependent.

Beach cats, for example really benefit from the lift of some helm angle, as their rudders are deep and efficient, but they have no other CB or keel. Other boats, less so.

But again, lee helm is always bad.

Bene505 02-01-2012 08:03 PM

I adjusted our autopilot a few weeks back and the course didn't change. Then I noticed that I had it in standby. The boat just tracked along.

Of course, I've sometimes adjust the sails to find a good balance, but I don't think I did that time.

Regards,
Brad

St Anna 02-02-2012 05:22 PM

Quote:

Originally Posted by Faster (Post 825105)
I think your poll is missing a response, along the lines of "normal 5 degrees or so, easily held" which would be, I believe, a common response.

On our boat (frac, big main small jib) the amount of weather helm varies greatly with point of sail. Close to beam reaching in a breeze can load up pretty good whereas on the wind it's just about right.

I do think it's preferable to lee helm...

yup, ditto to what 'speedy' says

Not fractional though, but works effectively the same

RichH 02-02-2012 05:44 PM

Sail SHAPE is the predominant factor affecting 'weather helm', followed by rig tension ... and lastly mast rake.
In that vein, its simply amazing that most cruisers never bother with sail 'shaping' to affect a near neutral 'helm pressure', heeling effort, etc. ... even for 'safety concerns'. Yes, CLR vs. CE is important ... but that 'really' only applies when hove-to, not sailing with dynamic or aerodynamic effects acting on the sails.

To remove 'weather helm' one must use 'tell tales' (such as described in www.arvelgenty.com and other sources who use that work as their 'root source', etc.) and perform the 'sail shaping' (via monitoring the full set of tell-tales) needed to get good/efficient aero flow across the sails ....... instead of futzing-around with mast rake, etc.
When one begins to 'study' tell tales and their usage, one has to totally forget & discount the erroneous 'crap' that has been taught for nearly a full century in US high school science classes ... and simply adjust and 're-shape' to what the tell tales are indicating.

For the most part even the worst of sailboat designer will have the 'balance' already designed-in or close ... all it takes is correct sail 'shaping' and tell tales usage to tweak that helm balance for the boat to be 'safe and fast', etc.

So, how much 'weather helm' ... about 3 of rudder angle, so that also the keel can generate 'lift' when beating... otherwise youre dragging the rudder through the water.


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