Heading Windward w/Jib Only

[Sailingflutist1954]

Is this possible? I found it not possible yesterday in very windy conditions. I am a newbie and need help. The (1973) DSII would not tack any direction windward no matter how far I turned the rudder and slid sideways as if centerboard was up (it wasn't; I anchored and jumped overbd to see). Is it the areodynamics of the sail position relative to the center of mass or forward angle of the leech (I blieve the name for the forward side of a sail) which screwed me or was I doing something wrong? I am not new to sailing. I have had a DSII about 20 yrs ago (forgotten much) and a Petrel SB-12 and a Scirocco 13 (both with main and jib and the later with 22 ft mast/110 sq ft SA! and a spinnaker 2 owners b4 me.) This DSII has 3 Harken winches unlike my other DSII and 2 mainsail trim adj on the anodized boom. Thank you for any good advice.

[GreenLake]

By using only your jib, the center of effort for your sailplan moves forward, while the center of lateral resistance (given mostly by the centerboard's location) stays behind.

As a result you get a large turning moment to leeward, which you have observed. If you try to counteract that with the rudder, the attempt fails. I'd guess the rudder never generates enough lift at small angles, and once you increase the angle further, it would stall (and hence not produce much lift). Lift for a rudder equals the force available to turn the boat.

Therefore, sailing under jib alone is fine for reaching/downwind courses, but upwind, you'd be better off using just the main. When you use just the main, the CB is overdimensioned and placed too far foward.

However, raising it to some degree fixes both of these problems at the same time, because the remaining exposed section of the CB will now be further aft.

So far the theory. It matches what I've experienced on the DS the few times I sailed with only one sail, except, I wasn't smart enough then to know about the trick with the raised CB. For that, I had to read the older posts here on the forum.

[Sailingflutist1954]

Thank you GreenLake. That sounds right. Not only aerodynamics but physics, too. It was my first time in this boat and my 17 yr old daughter not having much time for ol' Dad any more made time for the boat and me but prematuraly for me. I wanted to take the DSII out on a calmer day early and play with her all day till I was somewhat familiar before taking someone out but my daughter's time for me in her life is rare these days and I didn't want to miss it. We had quite an unforgettable time!!! I'm still recovering from a lumbar disectomy, have an aortic aneurysm @4.7 cm (near surgical replacement or rupture), and a thorasic herniated disc and 2 mini strokes last spring; that's why i went to a "smaller" sailboat than the 26-32 that I have been desiring for near a decade. Common sense won out; not to mention my physioabilities the larger amount of required $, time, maintenance, and just so much more enslavement is too much. I am trying to free my time and $ up to help others before I pass on. I love sailing and hope to develop a good relationship with this DSII. she kicked my butt yesterday, but I learned. "I'll get back on her again" soon. There is a lot of learning to do; but that is the reward; to to face and deal with the unknown and meld into the interaction as edifying friends.

[algonquin]

Greenlake nicely summed up the problem and the solution to move this very light sailing craft forward.

I sometimes expect more than this boat can deliver having been used to heavier and more stable (predictable) keel boats. It is important to keep in mind that the DS series is very light and it does sail well but is much different and livelier than heavier sister ships of similar length. It takes a bit of getting used to but as you build experience over time the DS will bring you a lot of sailing satisfaction. Brad

[ctenidae]

GreenLake's thoughts match my experience with only using the mainsail. Like him I didn't realize why it works, but it does. I was having a very hard time tacking with just the main until I lifted the CB about 1/4-1/2 way. Still not easy, and she doesn't point all that well, but doable.

[Sailingflutist1954]

Thanks sailing friends. I suspected it was a physics or areodynamics thing but didn't know for sure. I just acquired the boat and it was the first time out so it was possible that there was an imbalance in the hull due to covered repairs or a leak in the inner hull or my ignorance of a rigging or other technique procedure. It is good to know that it is just the nature of the boat and not my inaptitude of sailing or a boat defect. I really didn't think it was so difficult. I was just working with basic sailing not any high performance techniques. I have read in past years in "Good Old Boat" about many people sailing with just the jib, esp. strom jib, in high winds as I had that day. They had larger sailboats which apparently made all the diff.

[Cal]

I have sailed larger boats with just a jib, usually a genoa, and was surprised at how poorly my DS2 did with just the jib. Trying to catch the tide for a short sail with the grand kids, I skipped the main. Reach or run but it wouldn't point and needed some paddling to come about.

But it was a brisk reach across the bay and back.

Cal

[Sailingflutist1954]

Yeah, that is what I experienced w/my daysailer, too. Only after I paddled through a coming about and the wind filled the jib it defiantly moved to leeward again. Must be the genoa gave it more of that force toward the stern giving the centerbd/keel more bite to steer windward. I suppose the cleets/stays for your genoa's clew are farther toward the stern than my daysailer's jib-porportionally. Glad you made it out in time with the grandkids to catch the tide. I am not familiar with that consideration here on Lake MI. If you make it out in time how long do you have to wait for it to fill back in? From my fishing solunar tables I know that the moon's orbit takes around 25 hours and that there are two high gravitational effects from the moon- a major (overhaed) and a minor (the other side). For the tide probably the geometric plane touching the surface of the ocean tangent to the area considered extended landward and continued spaceward would give the approx elevation relative to the horizon where the moon would be for high tide and the opposite planeal extension for low tide? Since we wouldn't be disecting the earth with this plane the time between would not be even close to 1/2 half of time of orbit? Enough conjecture. What's the poop?

Jim

[GreenLake]

Tides are a complicated beast, because the landmasses and their shapes interact with the way the free water responds to the variation in gravitational pull.

Add to that the Coriolis force, which results from the fact that the earth is spinning and which deflects all moving masses sideways (be they water or air). As a result all oceans have their very own rotating tidal system.

Finally the shape, depth and extent of any bay or inlet connected to an ocean affects the timing and height of the tide as you obseve it on the shore.

Bryon D. Anderson wrote a nice little book called The Physics of Sailing Explained in which he describes this with some maps. The book is kept short and readable. However, as his description of tides indicates, he doesn't shortchange the reader by leaving out the interesting real-world complications.

Makes for a nice bit of winter reading.

[ctenidae]

Here on Long Island Sound, it's 7 foot tides running about every 5.5 hours. So, what' sbeautiful open waer in Norwal Harbor at noon is massive sand islands at 5.30. Fortunately the DS is shallow enough to get in and out of our mooring spot at low tide (but not low low tide), though we do have to leave the dinghy on the wrong side of the dock and wait for it to lift out of the mud before coming around and parking.

The interesting effect of the 5.5 hour cycle is that the tides are perfect for us every other weekend. This weekend, for instance, low tide is around 9 am, so if we do some errands in the AM, we can be on the boat by 11.30 or 12, and go out for as much as 6 hours before the water starts to get low again. Next weekend, though, we'll have low tide in the middle of the day, which means we have to go out early and stay late (oh darn).

[Cal]

That pretty well describes it. My Maine summer place is on a bay that has, on my side, clam flats at low tide for about 200 yards. Tidal range depends on where the moon is and can range from nine to eleven feet.

Today's high tide was 9.1 feet at 2.19 but there was almost no wind.

The 'shore' consists of ledge and sea grass about six to eight feet above the flats and the actual land is another six to eight feet above the sea grass.

At the time I had the DS on the sea grass tied to a tree and needed to get off, and back on, the sea grass in the 2-3 hours around high tide. I am trying to work out a mooring, but the flats have scattered rocks and the DS can find them at low tide.

Cal

[DoorCoMel]

Greetings from the other side of the "pond" (Sturgeon Bay, WI):

Your question about tides on Lake Michigan intrigued me. From what I have read (and observed) the lake is such a relatively small body of water that the solar/lunar pull accounts for only about an inch of tide, which is pretty much unnoticeable. What does make a difference, however, is extended prevailing winds from the north or south which tend to "pile" the water up at one end or the other and then the "wave" slowly moves back and forth like what happens when you lift one end of a pan or tub. This oscillation can last for a few days with regular (daily or thereabouts) water level rises and falls of several inches which can be mistaken for true tides.

An interesting facet of wind caused currents happens here in Sturgeon Bay, which is in fact a waterway between Green Bay and Lk Mich, the only thru channel across the entire Door peninsula for a distance of about 60 miles. I crew on a boat which races on Thursday evenings in the "inner harbor" portion of the waterway (about a half mile wide at this point). We never know what the currents are going to be -- depends on how much water gets piled up on the GB or Lk Mich side, I guess. And presumably GB and Lk Mich are all one hydrological system.


BTW, I have found that my DSII behaves very nicely under a reefed main and no jib on windy days. The steering trim is almost neutral.

Happy learning.

[talbot]

As an only-occasional saltwater sailor, the tide discussion is fascinating. To return to the original thread...
-- The jib alone works better when you don't need it. You can make shallow tacks when the wind is light. Useful for moving the boat a short distance across the marina with minimal hassle when the main is stowed or under its sail cover.

--In strong winds, while it's almost impossible to come about with the jib alone, you can easily jibe. So, just like you might to a 270-degree turn to avoid a jibe with the main, you can do a 270-degree turn to avoid coming about with the jib.

--I second (or third; I lost count) the assertion that a reefed main is a great option. It allows the boat to sail better without the jib, and allows you to keep the jib up longer in the first place. A jiffy reef system lets you quickly reef and shake out while under way.

--Question (this has been asked before on the forum, but I haven't seen an answer): Has anyone tried using a small (e.g., 75%) storm jib? If so, where'd you get it? Would it work to just use the jib off a smaller boat like a Lido or Puffer?

--Talbot

[GreenLake]

In 2006 someone mentioned he had been planing in the DS while using a storm jib. Apparently, some people are using them.

[Kleanbore]

I think either the JY or Flying Jr. jib would be perfect as a heavy wind sail for the DS.
In my opinion, the DS sails better at higher wind speeds without the jib, sailing on main alone. Reef it if ya got em.
Here in South Texas the winds either blow hard or hardly blow. A friend of mine came to town for a week of sailing. The white caps kept us off the lake for 2 days, so we launched early morning on the 3rd day before the wind filled in. Fill in, it did, but we were ready for it. We doused the jib (no reefs at that time) tightened the outhaul, used the hiking straps and the tiller extension. At one point going downwind on main only, the GPS showed close to 7 knots and we were surfing. Tacking was not a problem at all, but you really, really, really need to keep your head out of the boat, the sheets in your hand, and above all, never stop flying the plane!