Work took me to San Diego today, so I grabbed the early, direct flight and wrangled my way into an afternoon racing lesson with J-world. Mike from Cincinnati was getting a three-day private lesson, and let me share an afternoon. Today, in 21C sunshine and 10-14 knots of wind, three of us sailed a J-80: Mike, me and our instructor.
The people were easy company, and I was on-board the boat within an hour of touchdown. No motor, so we pulled the boat to the end of the finger dock, pointed into the wind, hoisted the main and sailed away, tacking every 20 meters. Mike was at the helm, I was on the jib. Piece of cake!
The J-80 is pretty similar to the J-100. It’s 2 meters shorter, but about the same beam. The first thing I noticed was that the mast had a lot of pre-bend. This made me curious, since we are still learning about our tuning. I assumed this was because the shrouds were tight, but they weren’t. VERY CURIOUS. The instructor thinks that their masts may have become permanently bent over time as people have left the backstays on overnight…and this might have been happening for 30 years. Whatever the reason, this had a big impact on the mainsail shape, and the interplay of the other controls. Simply put, the mainsail was quite shallow and flat.
Another difference was the traveler. I like the traveler on the J-100 MUCH better. With windward sheeting, we can play the traveler in gusts. Not possible with the setup on the J-80. This means the boom vang became important upwind, so that gusts could be managed with the sheet. We should still try this, especially for windy races.
But the most important difference I noticed was that the boat only has one lifeline, rather than a pair – and good thing I noticed that! Upwind I was hiking on the high side, and was about to slip my torso below the upper lifeline like we do on PERSPECTIVE. Just in time, I realized there wasn’t a lower line that would have been my ‘seatbelt’. YIKES! We would have been practicing our man-over-board lessons out in a gentle 2 meter swell!!
We sailed white sail, with mainsail (no reef) and a #3 jib (no overlapping genoa).
Since I was just there for one afternoon, Mike let me hog the instructor’s attention, and I learned quite a lot. My goal was to understand how to trim the mainsail for pointing and speed and what we should be doing about the backwinding we get in 10+ knots with the genoa. I’ll try to summarize what I learned:
- IGNORE THE LUFF. It is the back edge of the mainsail that drives pointing and speed. This is true even with a non-overlapping #3 jib. It is even more the case when we have a #2 or #1 overlapping Genoa. Bottom line: we can ignore the backwinding at the luff.
- TOP BATTEN ANGLE. The key parameter to optimize for pointing and speed is the angle between the boom and the top batten of the mainsail. The target (in 10 knots or so of wind) is for that batten to be parallel to the boom. To check this out, several times I lay down in the cockpit and looked up at the boom and the sail above it. With some coaching, I could see the angle.
- Boom Vang: On the J-80, we adjusted the boom vang to get the batten parallel to the boom.
- Traveler was mid-boat and sheet was on just hard enough to get the tell-tales streaming.
- Boom was a bit below center line
- Outhaul was almost maxed out (already at 10 knots)
- Luff of the mainsail (in 10 knots) was trembling.
- So at 10 knots, the mainsail was very flat, and it was trembling along its luff. Thinking about much mast bend was on the J-80, and the general flatness of the sail, it isn’t surprising that we get backwinded. NOTE: in higher winds (see below) and in lighter winds, more twist is desired, and the batten is deliberately angled away from the boom.
- CONTRAST this to what we were doing last year. We didn’t like the backwinding, and often put a lot of twist in the mainsail, with the traveler up to windward. The boom was certainly around centerline, but the top batten would have had a 20 degree (or more) angle to the boom. It looked good, and felt balanced, and we were fast, but we sacrificed pointing.
- BACKSTAY should be playing a different role than we’ve been using it for. I’ve been using the backstay aggressively when sailing upwind to flatten the main by bending the mast. The downside of this is that it opens the leech of the mainsail, and the top batten is no longer parallel to the boom. WE HAVE BEEN GIVING UP POINTING. Sure, we could compensate by trimming the mainsheet harder (or the boom vang), but we haven’t! The instructor used the backstay to manage weather helm by opening up the leech on purpose when we started to get overpowered. Once the wind built to about 14 knots, we adjusted the backstay and I was lying again on the sole of the cockpit to watch the affect. Sure enough, a bit of backstay added 5 degree increments to the angle between the batten and the boom. The weather helm was better. We did this before dropping the traveler. HMMMM, maybe we need to be managing this actively upwind?
- HALYARD & CUNNINGHAM. I was surprised how little attention was played to the tension on the luff of the mainsail. It goes back to point #1. Take a look at the second picture. This shows how the halyard was set initially (LOOSE) in 10 knots downwind. Okay, that’s cool. But when we turned upwind, we just tweaked the Cunningham to clean up the lower part. Later when we were sailing upwind in 14 knots, I asked again about the halyard and Cunningham, and the instructor said offhand,” yeah, I guess we could clean it up a bit. But that’s only a detail, focus first on getting the back edge of the sail right. In order of priority:
- Outhaul & Backstay
- Traveler & Sheet
- Halyard & Cunningham”
- JIB. In all of this, in order to point, it was critical to have the jib hauled in tight. Since we had a #3, and not a genoa, I couldn’t learn how tight is the right tight for overlapping headsails. But for the #3 jib, we brought it in tight. The spreaders had black tape on them 2” and 4” from the tips. To point high, we had the jib to the inner tape, jib lead car aft. The last two inches made almost 10 degrees in pointing angle. Hmmm, on windy nights with the #3 do we need to rig an INHAULER?
After this started to sink in, I came back to the fundamental difference in mast bend, and how we set up the boat last year (shortened forestay, no mast rake, controllable weather helm) vs the year previous (longer forestay, maximal mast rake, tons of weather helm). As a result of our discussion, this year I want to set up differently: intermediate rake for an even tighter forestay with more pre-bend and flatter mainsail to manage weather helm without sacrificing pointing.
That just about sums it up. I’ll follow up with J-world on the rig-tuning, but I think there is already plenty we can learn from in here!
Top Gun, here we come!