Sun Cat Headsail (jib) Seatrial 1

[capt_nemo]

Finally finished designing and fabricating two headsails to fly from my homemade Bowsprit protruding 4' beyond the stem. The Bowsprit was made to provide a platform on which to experiment and play with headsails for Sun Cat "Frisky". I was fully aware that when playing around with headsails I faced a challenge in not adversely affecting the balance of the rig against the center of lateral resistance below the waterline.

This post reports the performance of a large masthead hanked-on Light Air Drifter, which measures just under 75 square feet. It is the big sister to the original 38 sq ft Orange Nylon Drifter set "flying" from the original forestay. It was made from 3.3 ounce (per sq yd) Orange Polytarp which Dave Gray of Polysail International says is about the same as 2.5 oz Ripstop.

Keep in mind that I added ADDITIONAL masthead shrouds to the rig as well as the ADDITIONAL quick release masthead forestay to the end of the Bowsprit to take the additional loads placed on the previously unsupported masthead. The original quick release forestay was retained as a "Baby Stay" secured to the centerline bow cleat just in front of the mast.

Here are a few photos of the sail set up on the hard so I could get photos all round.







Visability forward under sail is excellent due to a designed 12" tack line.



Now for performance notes applicable for conditions of board all the way down and factory rudder fully down against stop.

Initially set without mainsail in very light air, less than 5 mph, the boat moved slowly but experienced slight lee helm and was somewhat difficult to steer.

With the main'sl set along with the Drifter the boat moved forward better, albeit slowly, and felt a little better balanced experiencing negligible lee helm to somewhat neutral helm.

As the wind increased a bit, above 5 mph but less than 10, the boat picked up speed, the Drifter drew nicely, and the eficiency of the main'sl was improved by the "slot" effect. Steering was effortless with near neutral helm and felt like power steering a car. "Frisky" heeled over slightly and seemed to be in her element slicing through the very light chop on the surface of the water. I tried tacking several times with the boat moving nicely and had no trouble whatsoever crossing over onto the other tack. I did find that like some other boats (especially in light air) it was better to oversteer a bit, bearing off on a close reach for the new tack, and then as the boat responded by picking up speed, harden up as much as a Cat Boat can harden up. Glancing up periodically at the tell tales on my main'sl it certainly looked like it welcomed the company of the Large Orange Drifter.

On Beam and Broad Reach the Drifter performed quite well indeed.

Fortunately all the designing, measuring, cutting, taping, reinforcing, sewing, and grommeting paid off. The Drifter more than met my expectations.
Intended to try out the other "working" headsail also, but enjoyed sailing with the new homemade Drifter so much that I sailed with it for a few hours before trailering back home. 

[Tom Ray]

This one looks like it will be far more effective than your little one, Don.

What is the "working" one like?

[bfelton]

Don,
      Are you using the an Ida high performance rudder?

Bert

[capt_nemo]

Tom,
The working one is made of 5 oz tan polytarp and is designed to be self-tending, either loose footed or club footed on a light boom - haven't sea trialed it yet to play with the sheeting arrangement. That's next.

Bert,
No, I have the stock rudder from the Factory, and unlike some others am satisfied with its performance thus far. Nobody has been able to convince me with hard data (I'm cursed in being an Engineer) that the performance differential is worth the cost of replacement or the hours of work to make one myself. l  also do not experience excessive weatherhelm as reported by some other Sun Cat Owners.

capt_nemo