fg rudder and weatherhelm

BCC Forum
1

hello out there.

i have owned my bcc for about three years and the first year was seven months out of the water doing much work. one of the things i replaced was a rudder. the old one was wood with holes in it (worms or or the like, i guess). the new one is fiberglass that i got from gary who owns “shante”. i seem to have an extreme amount of weather helm when the boat starts to heel. i have sailed under headsail alone (which i think should give lee helm?) and still the problem is there. the tendency to round into the wind is overwhelming to the point that it takes both hands and my feet braced against the leeward side of the footwell, and still i can barley manage. the poor windvane has no chance. it seems to me that the problem is the lighter, more buoyant rudder but all the builders i have talked to seem to think that highly unlikely (roger olson and todd at cape george among others). has anyone else had this problem?

jeremy j laurich
sea pig (formerly tremil sea)

2

Hello Jeremy,
I also had “fought” weather helm… until I rerigged. With appropriate rig tension, the weather helm magically vanished! And that is even with an asthetic rake to the mast. Run your numbers for tension and check them with a gauge and you may be surprised as I was as to how out of line things can be even when “looking” right.

Cheers,
Tom
“Terrier”

3

Jeremy:

In general the BCC requires a reef when the wind speed is between 12 and 14 kt, depending on point of sail. Most modern boats require a reef when the wind is 18 to 20 kt. The BCC carries about 680 sq ft of working sail area. This is the reason the boat can sail at 4 to 5 kt in 10 kt of wind. Most sailboats require at least 15 kt of wind to start sailing, unless they have light air sails.

At what wind speed does weather helm begin to build?

Rod
IDUNA

4

i have sailed the boat with a double reefed main in 15 knots and no main (just head sail)in 20 knots. the problems seems to get worse as the boat heels regardless of sail configuration. i must have something wrong with the rig if no one else with a fiberglass rudder has encountered this problem
jeremy

5

Hi Jeremy, did you notice any difference in the weather helm, between the wooden and F/G rudder ?

I don’t always remember where I read the info that I do remember, but I do remember that a sailboat rudder needs to be “neutrally” bouyant.

To me this means the rudder should just barely be able to float in the water, on it’s own.

The Foss Foam f/g rudder on Calliste floats like a surf board.

I had a very hard time to replace the rudder on the gudgeons and pentils, when the boat was pontoon berthed.

It took 3 diver weight belts, strapped to the rudder shoe, to reduce the bouyancy enough to get it verticle in the water and close to the gudegons, then it took two men over an hour ,to push and coach the rudder into place.

I won’t try re-mounting the rudder, when the boat is in the water, again !

With such a bouyant rudder as that, it seems only logical in my mind, that when the boat is healed, the free “trailing edge” of the rudder will try to float up !

Which helm that causes , weather or lee helm, I don’t know .

I would think that the wooden rudders are much less bouyant than the foam filled f/g ones .

Douglas

6

thanks for your comment … well anyway i have more tests to run and some rigging issues (maybe?) to resolve, then i shall add temporary weights and see what happens

jeremy

7

Well, the post about the rig tension is interesting.

But, if you are relatively new to full keel, cutaway forefoot boats, you may be new to this concept that the more she heels, the more weather helm she’ll have. There was a nice article in, I think, This Old Boat, about 2 years ago explaining the physics of this. Basically,as the center of effort of the sails leans over, it puts more twist around the center of lateral resistance of the hull. This is more pronouced on our type of boat.

I first experienced this in my Alberg designed Cape Dory (which I loved). The trick is to “Reef early, reef often.” Most boats sail best at 11-12 degrees of list and a BCC definitely does not wish to exceed that. As you get up to 15 deg heel, you need to be reefing. Your overall speed through the water will actually be better reefed and upright than if you are dragging rails and torquing the rudder.

I’m no expert, but my philosophy is, if you have more than a little weather helm, you have too much main up. You want a balance between main and headsail.

That said, a BCC does not sail well under one sail alone. She is not a Catalina 27 which you can dock under either sail, alone, without engine, easily. On the other hand, in a seaway or a gale, your BCC will take care of you and God help the poor soul in a Catalina.

I find the key is balance between both main and headsail (unless you are heaving to in which case you want triple reefed main alone: no headsail) and if you have more than 10 degrees of weather helm on your tiller or say 3 fingers strength or 5-7 pounds of pressure, you need to take in another reef in the main.

I cannot see how the weight of the rudder could have any appreciable effect.

Hope this helps!

Jerry
Destarte’

8

you could take a look and see if the mast rake has been increased over that of your fellow bcc’ers. that could be another contributing factor.

9

Jeremy,
I suspect that a very bouyant rudder will cause weather helm when you’re heeled. Unless you attach the weight to the trailing edge, the barn door will still be bouyant, won’t it?

I added glass cloth and epoxy to Shaula’s foam rudder as it was showing separation where the 2 halves are joined, and that may have helped decrease our rudder’s bouyancy. I was able to install the rudder in the water once, with some difficulty but not as much as Douglas had. Maybe different foam densities have been used over the years?

I agree with Roger that the mast should have very little if any rake, and that reefing the main is very important as the wind increases. We’ve found that using a balanced rig with the main and at least one foresail usually works better than either just the main, or just the jib.

BCC’s do great under wind vanes (ours is an Aries), so your problem is fixable.

Dan sv Shaula BCC #59

10

thanks everyone i really appreciate all the advice. i will spend the next week tuning the rig and trying different sail combos.

jeremy
sea pig out