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  #1  
Old 06-23-2003
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Pig to tack

I have a 27 foot Nova 27, built in 1972, and recently purchased. It is a very well built GRP sloop with long keel and transom mounted rudder. Sails very well, but is a pig to tack. In light to moderate airs, you have to back the genoa to get her to pass through the eye of the wind. It appears that it is a design problem. I am wondering whether to reduce the size of the main, or possibly to add a bowsprit, to move the foresail triangle about 18 inches forward.
I used to own a 1953 wooden double diagonal sloop, which suffered from severe weather helm, and the previous owner had tried all the obvious things like moving the mast, shortening it .. without success. Two years after I had her I saw her from a distance on the beach, and realised that the rudder plate was far too small. Made a bigger rudder... so problem solved. Point is, I am prepared to experiment.
Anybody got any ideas, or had a similar problem.
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Old 06-23-2003
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Pig to tack

Usually tacking problems come from a wide range of factors. In my experience the problem most often the problem is one of drag or a lack of a sufficient pivot point. In the case of long keel sailboats (and catamarans for that matter.) there is a lot of wetted surface and a lot of lateral plane. This large wetted surface tends to produce a lot of drag and so quickly slows a boat down reducing steerage.

Also on a long keeled boat (like a catamaran), the lateral plane is arrayed over the length of the boat so that as the boat rotates the forward end of the lateral plane tends to be forced further inboard than the inside of the turn and the aft end tends to be forced outboard the outside of the turn. In other words, instead of ''carving a turn'' a boat with a long narrow waterline plane tends to slide through a turn. This sliding produces a lot of drag as water is forced to aside by angular displacement of the turn.

Lastly, without a ''defined'' pivot point, and acting in the turbulent water at the aft end of the keel, attached rudders tend to be pretty inefficient. As a result there is a tendency to turn them hard over in a tack and that just further adds to drag.

A couple remedial thoughts here; first of all I would make sure that you have a clean, bottom with smooth bottom paint. You have a lot of wetted surface so a ''racing bottom'' is more important to you than to a racer. I would experiment with making slower turns, which would mean a slower more deliberate turn with the rudder at a smaller angle. In other words, carving a turn. I would also consider using a smaller headsail as the wind resistance of a large genoa during a tack might be adding to your problem.

If you decide to get more extreme, I don''t think that a larger rudder will cure your problem, as it would only add more drag. When I lived in Savannah I was hired to design a solution for a 38-foot ketch that could not be tacked without its engine. In that case we removed the keel-hung rudder and faired the trailing edge of the keel. I then designed a transom/partial skeg hung (actually stern post hung since this was a double ender) rudder that was separated from the keel. This actually improved the behavior of the boat dramatically to the point that it could reliably be tacked and backed into a slip as well.

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Old 06-23-2003
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Pig to tack

As a catamaran sailor, I think Jeff is probably close to the mark on possible reasons your boat doesn''t tack readily. In addition to his suggestion to be more deliberate in "carving" your turn, if you are carrying a large genoa, the force of the wind on this sail may be making it harder for your boat to round up quickly. Try easing/luffing this sail just before you start your turn; with the wind pressure shifted aft (pressing on the still-sheeted main), the wind should help pivot the boat, or at least slide the stern around better. You may need to quickly sheet in the genoa once through the wind (and/or ease the main momentarily) to prevent the wind from pushing you back into irons once you are through the wind (a light catamaran, like a Hobie 16, needs to backwind the jib and ease the main, because you lose a lot of speed tacking, and the wind tries to pivot you back into irons when it hits the other side of the mainsail). Your boat is undoubtedly heavier, but it''s still better to have the wind pressure working in your favor than against it when trying to tack.

Allen Flanigan
Alexandria, VA
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