Lee Helm

[orion27]

I was wondering if there is a possibility my daggerboard is not dropping completely.
Is this issue from time to time on other boats? Boat is dry sailed with an unpainted bottom.
I seem to have developed some lee helm but the symptoms are a bit confusing.
Fully trimmed the tiller handle is slightly to weather or neutral. At times I
have to drive the boat up to weather. If I let go of the tiller the handle the swings
to weather and the boat takes a dive to leeward. The only thing I can figure is my
daggerboard is not fully down. I'm sailing PHRF with a 31' 10" headstay. One year
old set of North radials. Rudder is fully down with the conventional pin across the
blade. Is there a measurement I can take from the top of the daggerboard to the
coach top in the water to determine if the board is all the way down? Last race
was sailed in 10kts of breeze. Thanks for any and all comments.

[dave]

I guess that's possible but I would bet that your rudder is kicked under a tad too far. The trailing edge of the rudder needs to line up exactly with the trailing edge of the keel to be balanced correctly. One way or the other you need to pull the boat and put it on pads or a tall trailer to check both things.

Don't put your faith in the factory lockdown pin/hole as far as setting your rudder right. You need to check this as I said.......................... CAREFULLY, and probably drill a new hole for the pin.

[orion27]

Thanks Dave, hard to believe such small adjustments can have such a dramatic effect.
I recently added two coffee can lids as bushings between the blade and the cheek plate.
This seemed to help keep the blade tighter between the cheek plates. I not comfortable
with a sloppy rudder. The last two races have been in light air. The blade might be pushed
to far forward and not coming back to butt up against the pin in the light air. Do you
recommend actually pining through the blade?

[dave]

I wouldn't sail the boat without pinning the blade. If someone is really that worried about running aground and having a rudder that will kick up, they should likely be sailing somewhere else!!!

I have allude to this fact before: I raced cats for 19 years all over the country. Cats have TWO rudders so getting them right is doubly important! The amount that the forward lower tip of the rudder blade is raked fore or aft makes a HUGE difference in boat performance, driving comfort and safety. Cats rudders are maybe half as deep as the 7.9 blade and on cat rudders having the blade tip only 1/8" too far forward or too far back can make the difference between auto tack weather helm and auto jibe lee helm!!!

I'm not a betting man, BUT, I'll bet you that the factory lock pin hole is in the wrong spot. The only other thing that I'd ask or add. Is this on both tacks? If not then I'd say that like mine, your daggerboard trunk isn't glassed into the boat centered from front to back. One my boat the back of the trunk is at least 3/8" off center with the front edge, which angles the leading edge the the starboard side. This not only makes the boat point better on starboard and worse on port but also makes for more helm load on starboard and less on port. This REALLY blows, but I've never looked at any two 7.9s which had the trunk glassed in at the same angle, and only one which was darn close to center line! That sucks but there it is!

[Tim Bosma]

If you are still worried about the ability of the rudder to kick-up if you touch (rocks, bottom, etc) then you can use a sacrificial pin such as a #2 pencil, Bic Stik pen, maple dowel of appropriate diameter, foam filled McDonalds straw, something that will hold under normal pressure, and give way under duress (kinda like out navigator!)

[orion27]

Just to be clear I always pin my rudder I just asked if Dave if he
recommended pinning "through" the rudder blade itself. Silly
question . Thanks for all the good info!

[dave]

Yes, I drilled a hole through the housing and head as far from the pivot point as possible and up out of the water wash.

[Tim S.]

If the problem is new, and you haven't made changes to anything that would affect the hang angle of the rudder, I would check the rudder for any signs of stress at the bottom of the rudder head. My boat developed lee helm just before the rudder snapped off last year. Broke right along the bottom of the rudder head. Seems it was just too many years of compression and tension cycles on it, and also, when I was removing glass from it, some of the cloth was never wet out.

When repaired it, I purposely laid up the top to be shorter than original, and flat. This way, I could screw a flat shim on it to contact the pin, and make the shim whatever thickness it needs to be to have the correct angle. Also, the top of the rudder had a radius to it before, and would bend the pin because it only contacted it in the middle. Of course, that would change the angle, and add weather helm as it bent -- not good.

The easy way to get the angle right, is to remove the assembly from the boat and measure it. Since the transom is perpendicular to the waterline, and the front edge of the rudder head is parallel to the transom, you just have to put a long straightedge against the trailing edge of the foil, and ajust the angle until the distance between the straightedge and the front edge of the rudder head is the same at the top and bottom. I did this, and then measured the shim thickness I needed to make between the rudder and pin. Worked well, and the helm feels nice and neutral like the other 7.9's I've steered. I do have holes for a bolt through the rudder head, but I haven't redrilled it through the rudder since repairing it. My setup seems to hold the correct angle just fine under sail, and we keep the rudder up at the dock to keep it clean, and regularly go in shallow places with the kids, so having the other bolt in would be inconvenient anyway.

[orion27]

Thanks for all the suggestions guys. The rudder is strong and there is no evidence of failure.
I will be sailing our Friday night race this evening and I will report back after the race.
Planned adjustment is to close the gap between the pin and top of the blade which was
approximately 1/8+. Don't know what this translates to down low

[dave]

Tom, if you don't know then you're just guessing! That's why I get it lined up right and drill a through hole: no guessing!!!

[orion27]

I appreciate that. I will take some measurements when I get the rudder on the boat. With the head of rudder butted
up against the pin now, the blade is in plane with the rudder cheeks whereas before i.e. pushed forward, that
was not the case. So I will take some measurements and use the in plane setting as a starting point. Hey Dave,
I value your input so let's keep talking.

[dave]

You will be AMAZED at the difference in feel and pointing! Most boats actually point the best with a heavier rudder loading, but it gets to be fatiguing after a long day of steering. With the max headstay length the 7.9 rudder is already loaded like crazy, you just can't feel it because the rudder is so counterbalanced.

Something that I just now remembered and one more GREAT reason for drilling and pinning the blade. Due to the location of the pivot bolt in the 7.9 rudder head and the fact that the rudder has positive buoyancy when submersed, the rudder will actually FLOAT up, and it can't tilt backwards because of the factory pin but it can and WILL tilt forward [up under the boat] unless the pivot bolt is extremely tight!!!!!! Sorry for just now remembering this, it's something that I learned about the boat seemingly eons back. My hard drive is full enough that recall is sometimes not what it should be!!!

[Tom Elsen]

Tom, did you change your rig tune in any way?
Or did the settings change themselves, by spinning off?
I agree that the rudder is the most likely cause. Sometimes it will 'wiggle' loose enough to kick around a couple of degrees.
Lastly, any possibility of weeds where you sail? Those will give you lee helm every time.

[orion27]

Sailed last night and I'm happy to report the small adjustment to the rudder angle
made a dramatic difference to the helm. I'm just amazed the small adjustment
made such a difference. Thanks!

[dave]

Glad that it worked for you, I was 99.9999% sure that was the problem. It's amazing what cats can teach you!

Not to hijack this thread or get too off topic, BUT: Monohull sailors loath catamaran sailors and have no respect for their sailing abilities. As in all sports, cross training is often the best way to improve at your chosen activity. Granted, If you never sailed anything but a Hobie 16 [POS] you won't learn much except the dramatic effect that slight changes in course can have on apparent wind speed and angle and boat speed and angle. If and when you move on to a cat that can actually tack, has great controls and has good upwind capabilities, a whole new world of sailing opens up and everything that you learn WILL effect the way that you sail a monohull from that point forward.

Example: Many people say that cats aren't tactical because they "can't tack". That is pure BS, but the point is that they are going SO MUCH FASTER when not tacking that you must choose your tacks very wisely. Cats are more of a strategic machine WHEN compared to most monohulls, but that is a good thing to bring back to the monohull sailing because it puts a greater emphasis on picking the right spot on the line, picking the right side and how closely entwined those two things are. It does you no good at all to pick the right side for the first upwind leg if your starting position prevents you from going that way! This hurts bad enough on a heavy monohull but you can usually pick you way through to a half decent outcome if you're a good sailor and pay attention. Do this on a cat in a fleet with the same relative sailing skills and you had better hope that the race is LOOOOOOOOOOOOOOOOOOOOOONG, because you may never be able to overcome that first bad decision!!!!!