3. Once boats are going as close to same speed as possible choose one boat to change one sail.
4. Test and repeat as needed to determine if new sail is same, faster or slower. In order to do that you will need to:
- Swap sides so each boat is to windward and leeward
- Once you have a feel for the new sail, swap sails from boat to boat and test again to try and repeat result.
It helps to have skippers of the same ability and also an experienced sailor in a powerboat to check trim on both boats. Having an extra person observing helps to speed up the process and keeps everyone honest.
For our testing we were looking to validate the speed and shapes of our existing 3DL sails vs. the paneled sails they are based on. Also we wanted to take a look at a new spinnaker design we’ve had in the work for a while. We also wanted to take a look at some different set up and trim options for the boat. Here’s what we learned:
Our new 3DL genoas represent a huge improvement in the engineering of a small boat genoa. With all the yarns in the sail oriented in the correct direction to capture the loads in the sail the structure of a 3DL J/24 genoa is drastically more efficient than that of even a paneled radial sail. Our experience and that of our customers has been that these sails are quite fast and easier to use in over 12 knots of wind. For our purposes we wanted to check to make sure the sails were fast towards the lighter end of the range too. Luckily both Seattle and Newport provided those conditions.
We are pleased to report that with a couple of small trim changes to the 3DL genoa the sails are as fast if not faster than the paneled sails in the lighter stuff. Combined with 3DL’s superior shape holding and speed in the breeze we feel that gives 3DL a significant advantage over the range of conditions you might see in a typical event. Changes we made to the trim of the 3DL sails in lighter airs are:1. Move jib lead 2-3 more holes forward compared with paneled sail.
2. Keep luff of 3DL genoa just smooth in lighter winds. Due to the fact
that the 3DL genoa is molded over a three dimensional mold sailing
with the typical “scallops” in the luff of the genoa in very light air
forces the draft out of the luff very quickly making the sail hard than
necessary to steer to in light winds. We found that keeping the luff of
the sail just smooth, not tight was ideal.
The shape differences between the Newport and San Diego 3DL genoas were evaluated as well. The sails have similar entry angles with the San Diego genoa being straighter in the back. This is by design with the San Diego genoa being skewed more towards open water sailing and stronger breezes. We were able to test the sails against each other and found that while very close in speed the Newport genoa had a little bit more “grunt” in light air and chop which was to be expected.
Question received from a client: In the above photo, looking at the windex, I’m guessing the boat is about 15 degrees up from dead downwind. The spinnaker pole is way forward of square to the apparent wind. Is this a typical position, and if so, are you doing that to keep the airflow attached longer? What is a good way to know if the pole is rotated fore/aft correctly?
Answer from our expert Chris Snow: Actually in the photo our sail designer was encouraging the boat with the white kite to sail with the pole further forward and it seemed faster. You are right that, usually, we sail with the pole perpendicular to the wind. However, and I think this helps more in light air, getting the spinnaker out away from the boat is fast too. That why I think having that pole a little forward of ninety degrees to the apparent wind can help. It also might make the sail a little fuller (by bringing the tack and clew of the spinnaker closer together) and that will make the sail more forgiving to trim.
We’ve tested the Newport SlantNose vs. the San Diego FR-2 and have always felt that the Newport SlantNose has a small advantage once the breeze is over around 8 knots and the boat can be sailed close to dead downwind. The flatter sections of the SlantNose give the sail a bit more projected area. The flatter sections make the sail a bit twitchier in lighter winds when the breeze is more forward on the boat.
For our test we made a modified version of the San Diego spinnaker to test. A bit deeper in the head, this sail showed lots of promise and will be tested more. Adding a bit of shape helps to make the sail even more stable. Additionally it allows the sail to be eased more and flown further away from the boat which is always fast with any spinnaker. Look for more on this updated design shortly.
We also took a look at two mainsails for future development. One was a radial foot sail that was developed for the Pan Am Games where the boats were sailed with just the class jib and 4 crew. This sail is significantly fuller than our standard mains and showed good promise in light air and chop. We were not able to test this sail in more pressure and so will continue to take a look at it going forward.
We also were able to take a look at our new team mate, Max Skelley’s mainsail design. Due to the limited time after the other testing this sail was not fully evaluated but according to Max and from what we saw certainly deserves further checking.
At North Sails we are constantly looking for ways to make our sails better. The effort that goes into these sessions is more than justified to give our clients the fastest, and just as importantly, easiest to trim sails we can provide. Please contact your closest North representative for more information.