What's faster, questions on balance while cruising long distance

[markxengineerin]

On a reach in 10-20 knots, my boat has some weather helm no matter what I do with the main sail.

What's faster, a full size and trimmed main, with lots of rudder correction for the weather helm? Or A 3rd reef in main, letting it luff a bit, and less rudder correction to maintain course?

Another related scenario, what's faster, autopilot steering the boat to a destination compass heading, or letting a windvane (or autopilot in Wind mode) zig zag the course +/- 20 or so degrees as it typically does? No sail adjustments in either case.

I would like to do what's fastest, but don't have the equipment (or consistent wind conditions) enough to figure this out easily on my own. I made a poor effort and could not draw any conclusions either way.

Thanks!

typical chart, wish I had rudder angle on here too, could be added:

[s/v Jedi]

Did you use the traveler?

[markxengineerin]

Yes, traveller is almost all the way out in all cases. Beam reach, apparent wind right around 90 degrees +/- a little. I'm not sure if that is the correct traveller position, but I've read to use that more than the main sheet, can't remember why. The effect seems very similar, I guess the main sheet pulling slightly more "down" on the boom vs. side to side for the traveller.

[AnsleyS]

The answer to your question is that a boat sails better with very little weather helm. The hydrodynamics far outweigh the aerodynamics.


First, pick a jib (or roller furl) that is appropriate to the wind speed, trim it to the course and then balance it with the main using the sheet, traveler, reef(s) and luffing if absolutely necessary. A small bit of weather helm is good to keep her from falling off.


After tuning the sails and helm balance try tuning the autopilot and windvane. I think that you may be able to reduce the twenty degree wobble. If you can get them to operate better together then sailing with them will enable you to take advantage of lifts that may come your way.


Have fun with it. This is one of the great joys of using the wind rather than the diesel.

[TeddyDiver]

Nothing you asked has a simple answer. Too many variables, boat, sea state, wind, current, VMG etc. Just try and learn.

[Nekton73]

I spent too long composing my post and others have covered what I said, so I'll change it and just say that I think you would benefit from experimenting in calmer wind conditions and learning to use your entire sail plan before heading out into 20Kt+ conditions. As others have said, have fun and play with your boat.

[markxengineerin]

Thanks, that's a better way of asking the question- "which more important, hydrodynamics or aerodynamics". Next question is, how much rudder angle is "ok"?

The steering wheel, which can rotate 1 full turn cw or ccw, is at about -100 degrees when I consider it "obviously bad" helm, with an weird looking wake out the back. Under "seemingly ok" conditions, wheel maybe -30 to -45 degrees. I do not recall the relationship between rudder angle and wheel angle, I'll check next time it's calm.

[markxengineerin]

All of the above is running a 130% genoa and staysail, both. Maybe that is too much, but wouldn't more headsail area reduce weather helm? Head sail choice was made based on the heel angle being acceptable, without consideration for balance.

The boat is a pacific seacraft 37, which is known for being balanced, so obviously I'm doing something wrong. I haven't cared in the past to look for the extra 0.5 to 1 knots, but with 3000 miles ahead (crossing from Canaries to Carib) it will make a difference.

[rslifkin]

Depending on the boat, weather helm can come from either an unbalanced sail plan or too much heel. On some boats, once you heel beyond a point, weather helm increases rapidly regardless of how the sail plan is balanced.

30 - 45* of wheel input without obvious rudder turbulence in the wake is likely not a concern. Some weather helm isn't an issue, and can actually help performance upwind. If the wake is getting weird from rudder turbulence or you have the wheel turned 90+ degrees, that's likely too much weather helm.

From the full sail plan my first reef on that boat would likely be to drop the staysail and go to genoa and main only. Second reef would be to put a reef in the main. Third would be to swap the genoa for the staysail, then fourth would be a second reef in the main. Order of doing those last reefs will depend on how the boat balances. It may be better to put the second reef in the main before you swap to just the staysail up forward, or it may not be, but you'll have to try it to figure out which works better.

[flee27]

All the above is good advice. IMO with all the head sail you have up and a third reef in the main, the weather helm issue would have to be from too much heel. Unless there is some other rigging issue. Mast rack not correct maybe?

But it also doesn't seem like the sail plan you are describing would case a heel angle too high with apparent winds below 20 knots at that angle of sail.

Best
Foster

[donradcliffe]

First of all, the majority of your time between the Canaries and the Caribbean will be spent running, not reaching. Adjust your sail plan accordingly, but that's another discussion.

If you really want to talk about a reach where the true wind and waves are on the beam, weather helm is not fast. Not only is it not fast, the autopilot will use more power and will be more likely to fail. Therefore, move your center of effort forward by reducing the size of your mainsail. It depends on the wind strength, but the optimum may be to take the mainsail down. Keep an eye on the amps being used by your autopilot.

The more you heel, the more current the autopilot works to keep you on course. If you have the main down and the wind increases further, it is time to get rid of the staysail and partially furl the genoa.

The only time you will go faster in apparent wind mode is when you are going to weather, where the constant wind shifts mean you are either luffing or overpowered.

[markxengineerin]

No, heel is not excessive. Do you mean mast rake? My mast is bent "back" slightly more than would be normal for a cruising boat, where they are usually straight.
The rake (separate thing) was set by a professional rigger and looks ok to me.
I would not be surprised if there was some other rigging issue. The only other thing I can think of is that I reinforced the skeg of this boat, made it a bit wider. It's a skeg hung rudder. I may have increased it by 1/8 to 1/4" with additional layers of carbon fiber because I didn't like how easy it was to flex. Now it's rock solid, but maybe the extra width is messing up the flow over the rudder? Grasping at straws.. probably something I am doing wrong with adjustments. I'll make some videos on a convenient day.

Edit: trying the same condition with the main completely down will be interesting, I avoided it because it seemed crazy, maybe it's not.

[Bowdrie]

Wind close to beam with full main, a 130 and a staysail in 20Kts? That's too much sail.
As has been posted; put a reef in the main, drop the staysail.
Once the rudder gets over ~5 degrees angle the drag starts climbing.

[markxengineerin]

10-20 knots, varies, see graphic in first post. Would too much headsail cause weather helm, by itself, in a normal, properly set up boat, that's not heeling excessively?

[s/v Jedi]

- traveler out
- outhaul not all the way in
- sheet tight, use traveler and tell tales for trim
- do jib changes to find balance. Experiment lots.

#1 reason for weather helm is heel. When you heel the shape of the submerged part of the hull changes from symmetrical to asymmetrical and the more you heel, the more asymmetrical it becomes and this steers the boat into the wind.

So don’t think more headsail helps… if it heels you more, it doesn’t help.

Your boat is well balanced so experiment with the headsails but a rudder angle of 4-7 degrees gives a better performance than 0 degrees because the sail trim isn’t optimal when trimming for neutral rudder.

For upwind sailing many boats can get a perfect trim, even during gusts and you can just let the rudder go free. I once sailed 6 hours without touching the rudder, just let it go and trim the sails.