Balancing the rig

[Ian McColgin]

One of the wonderful things about having WoodenBoat Magazines all neatly in order on shelves next to me is that I can pluck at random. Now that stuff is on-line, some random sharing is also well.

How to balance a rig? Go to #108 for John Gardner's marvelous treatment, including the homage to Chapell that CE and CR are really fictions.

G'luck

[tprice]

Those who worry unduly about rig balance simply have to look at how race boats shift from a # 1, #2, #3 headsail and put in 1 or 2 reefs, hugely altering the CE of their sailplans. And they still can be easily made to balance out just fine.
And, the CE and CLR centers have little to do with the planforms (outline) anyway. Their airfoil shapes generally move them forward to some degree.
To complicate (or actually simplify) further, they migrate around anyway, with heel, speed and sail trim.
Look at enough good boats and you'll have a good enough eye for it.

[ahp]

Remember that Capt. Jack Aubery was very careful about the fore and aft distribution of ballast and stores on HMS Surprise.

[donald branscom]

With full sails up, can you steer with wheel or tiller with two fingers?

[StevenBauer]

With full sails up, can you steer with wheel or tiller with two fingers?

In how much wind?



Steven

[Ian McColgin]

I should have made clear that Gardner's article addresses how to design a rig when none is provided or you want something different.

While various centers change a lot given the weather, a good sail plan accounts for that. For example, like most catboats, Marmalade has an impossible weather helm if she's over-canvassed. But interestingly, Brewer had the genius to give her a lee helm if undercanvassed. Many sloops run fine enough under genny alone that some lazy sailors use dropping the main as a quick reef. In really light conditions that would be a bad lee helm. Point is that how you shorten sail is very individual to the boat and the conditions, which you learn by experience, but has little to do with the initial design.

The centers are indeed fictions as they are static lateral measures of forces that are not really located there at all. But that's why we have so many good rules of thumb.

My favorite rule of thumb is litterally a rule of thumb. For small open boats of traditional design, the center of lateral sail area (misnomered CE) should be one thumb width ahead of the center of area for centerboard, skeg and rudder (misnomered center of lateral resistance) if the plan was drawn 1-1/2" to the foot.

G'luck

[Yeadon]

Aaaargh. I need to go find a copy of this Gardner story right now.