How Do You Guys Maintain Sail Perfect Trim On Port Tack?

On my Laser I've got a couple of sets of tell tales varying distances back from the mast that let me know when I'm starting to get out of trim. On my Sunfish I've got a similar set which work very well when I'm on starboard tack because the flow is not affected by the mast on that tack.

But as we all know, when you're on port tack the mast is creating a disruption of the flow on the leeward side of the sail, which pretty much makes the leeward tell tale on that set useless. I'm curious to hear how you guys deal with this and stay in trim and powered up while pointing.

Here's how I do it. A bit back from the luff just above the top of the mast, I've got another set of tell tails. On port tack, these are in clear flow... because they are above the mast. I do watch these on occasion but because they are way up there, they are a pain to look at with any regularity. Also, if you've got a bit of twist in your sail up there (looser vang, for example) those upper tell tales may show trim where in fact the sail as a whole may be over sheeted a bit.

I also... for super light winds... have a set on the window. So I watch these also when on port tack. These can show attached flow on both tacks... because they are so far back... but because they are so far back from the luff, there may be separation of flow on the leeward side migrating from the upper boom back towards the forward tell tales but you can't see it because your forward tell tales are getting rotored by the mast.

So, for example, when I'm pointing on port tack, I'll scallop my way up wind... meaning I'll slowly head up while watching the leading edge of the sail at the luff where the rings attach the sail to the upper boom until I just begin to see that leading edge start to quiver. That quiver you get just before the luff starts to... well... luff.

As soon as I see this quiver, I'll head off a few degrees... all the while paying attention to my boat speed. Then I'll repeat the process, keeping my boat speed up but while continually testing how high I can go... so that I don't miss a 5-10 degree lefty lift that I could have used but didn't because it wasn't shown on my forward tell tells like it would have had I been on starboard tack and gotten a 5-10 degree righty lift.

Anyway, would love to hear how you all deal with this port tack sail trim issue. Especially when trying to go upwind as fast and as high as possible.

Thanks!

- Andy

I've this same "scalloping" technique on all my various sailcraft. Having a jib helps.

Do others here find they point higher on port tack than starboard—but go faster on starboard tack? My sailing lake has many islands, which helped to gather this perspective. Is this due to the sail's center of effort being slightly more aft on port tack?

I have tell-tails, but haven't yet installed them on my new Intensity sail. My previous racing sail (which the previous owner had raced) had tell-tales about one foot back at about 18" above eye level, and another pair about four feet from the peak. Actually, those upper tell-tales were placed so it appeared the Sunfish logo was chasing it—as if live bait!

Andy,

Your question is quite 'technical' and I can only make a few points that may, or may not, be relevant.

In an interview Dave Loring (two-time World Champion) states that he doesn't use any tell tales because he wants to focus on what happens on the water. Of course, Dave has decades of high-level experience racing dinghies (Laser and Sunfish) and, I imagine, has a feel for the boat that mere mortals such as me, will never achieve. Keeping your head out of the boat is good advice though.

On the other hand, Scott Kyle, an earlier World Champion, recommends two sets of tell tales. The first one at the top to the third (middle) panel, ~30" from the gaff. He places the second set at the bottom of the second pane, ~26" from the gaff.

Just about everybody agrees that, going upwind, sailing really close to the wind (pinching) won't make you win a race. And that on port tack, one should foot off a bit more. Of course, waves and wind strength come into play as well.

I will be curious to read what you find out, 'playing' with the tell tales, and using an aeronautical eye.

PS: Years ago I was at a regatta where Dave Davies (a National Champ, as I recall) had his whole sail covered with tell tales. I didn't quiz him on that, but I imagine that he really wanted to study air flow across his sail.

PS #2: The search function will reveal that the topic of 'tell tales' has come up several times in the past. But I couldn't readily find an answer to the specific question you asked.
Another link: http://sailingforums.com/pages/Sunfish_FAQ/#Where do I put telltales

Wavedancer,

Thanks for your insights. I think my problem is I'm just too curious... wanting to examine and ponder every little nuance. And the funny part is, I go dinghy sailing to relax!

Cheers,

- Andy

These comments and advice are very good . Up until 12 months ago I lived on the east coast and was an active SF racer. Let me know if you are going up to Tomales Bay sometime and perhaps we can sail together for an hour or two. My wife wants to sail around the bay too thus just the hour or two of solo speed tuning. Chris

Hi Chris,

I don't know where you live but one place we've been sailing a lot lately is from the boat ramp at the 9th Street Park in Benicia. It's located just under 3 miles east of the Carquinez Bridge where Route 80 passes over the Carquinez Strait. Here's a Google Earth screen shot of the area looking due west.



When you have any kind of onshore gradient in the Bay Area, it always blows at this place. Day and night. Last Sunday, we were on the water at 9 am sailing in 15-18 mph west winds. I'm teaching a friend who lives 5 minutes from this boat ramp to sail and we were doing broad reaches in the "Flat Water Area" of Southhampton Bay.

Later on I left my friend to his own devices to work on his techniques so I used the time to sail upwind in my Laser to the Glen Cove area at the top of the photo. In that narrower area it was blowing over 20 at times and the tide was coming in at 3 knots so I had lovely flat water and several miles of high speed downwind broad reaches as my reward on the return trip.

Having sailed this spot a number of times now, here's 3 things I like about it.

- Being a natural wind tunnel, it blows pretty much all the time. And early in the day a lot of the time.
- It's warm. No cold ocean water.
- For less experienced sailors... like the guy I'm teaching... the flat water area in Southhampton Bay is really nice.

Cheers,

- Andy

chris williams said:

...and was an active SF racer... thus just the hour or two of solo speed tuning.

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I'd be happy to show you some of our sailing spots... if you'll teach Greg and me how to make our Sunfishes go fast!

- Andy

That looks like a good spot - I live in SF so it is an easy trip. I'd like to check it out some time. Chris

andyatos said:

On port tack, these [tell-tails] are in clear flow... because they are above the mast. I do watch these on occasion but because they are way up there, they are a pain to look at with any regularity.
- Andy

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While sailing yesterday, I noticed that a portion of my new sail that has the only hand-tied "tie" responded earlier than the rest to the wind. (That one "tie" is slightly tighter at the halyard hitch than the other standard clips on the luff).

If I can locate a magazine-sized piece of new sail material, a sheet of mylar plastic, or even a SAIL magazine's cover page, I will tape its windward edge to the luff—above the mast—and see if it doesn't give an audible response.

andyatos said: ↑
On port tack, these [tell-tails] are in clear flow... because they are above the mast. I do watch these on occasion but because they are way up there, they are a pain to look at with any regularity.
- Andy

Click to expand...

The above magazine cover (a Professional Boat Builders magazine cover) didn't survive the launch. However, a 13"x14" sheet of thin plastic (a "Posted-Private" sign—but much thinner than the usual material) worked very well—especially annoying when the wind picked up to above 15 knots. I stapled a sheet to each side of the main just above the halyard hitch, and the result was a gratifying rattle just as the luff stalled.

'Course, if you still look up to verify the audible "stall-warning", you'll still get a stiff neck!

I'll try out a smaller, more reasonably-sized, piece later. Maybe one of similar stiff plastic material the size of a tell-tale? Would such a "stall-warning" be legal for racing?