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Tacking Angles on a C250

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Tony Partain
1st Mate

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USA
93 Posts

Initially Posted - 06/10/2004 : 12:26:52

How close to the wind can you sail? I am curious as to the difference between the water ballast boats and the wing keel. After tuning on my rig I have made a difference of about 4 degrees closer to the wind from the way the previous owner had the boat tuned. Some of it had to do with the rig tune and some in the jib car settings. So how close can you sail to the wind?

Tony Partain
Bend Oregon

Edited by - on

bear
Admiral

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USA
909 Posts

Response Posted - 06/10/2004 : 12:41:19

Tony, I am not a rigger by any stretch, but I do try once in awhile trimming the main and jib. On Tuesday at times I was almost dead on according to the Windless. Later this month hopefully I will have Don Peet
out with me for a lesson on all this. "Bear" C250 WB

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Arlyn Stewart
Master Marine Consultant

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USA
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Response Posted - 06/10/2004 : 13:23:15

Tony, it would be very hard to do a cyber comparison... far too many variables. More important I would think would be individual observations of adjustments.

Keep in mind for example that the high freeboard, light displacement, and large sailplan all contribute to increasing tacking angles with increasing winds.

Keep in mind, I'm referring to tacking tracks rather than headings as headings are really a trap to focus too much on. The focus should be on the tack track. This can be gleaned from the gps rather than the compass.

In strong winds with a significant surf... track angles for the 250 can become 120-135 degrees or more. I've never experienced a track angle on my 250 that comes close to those enjoyed when I raced Hobie Cats. They enjoyed a track angle between 90-100 degrees.

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Steve Milby
Past Commodore

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Response Posted - 06/10/2004 : 14:41:28

One of the big variables regarding tacking angles is the ability to generate boatspeed. Generally, as boatspeed increases, the apparent wind increases. As actual or apparent wind increases, the boat's ability to point to weather increases. Therefore, a boat that is in top racing trim, with smooth bottom, keel and rudder, well-tuned rig, fast sails, and skilled crew is capable of generating greater boatspeed and sailing closer to the wind than others. That's why Arlyn's Hobie was so close-winded. On a good puff, it could generate twice the speed of a C-250.

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Tony Partain
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Response Posted - 06/10/2004 : 17:09:22

My first boat was a Hobie 20 and enjoyed those great angles but had a hard time overnighting on the trampoline

<blockquote id="quote">quote:<hr height="1" noshade id="quote">In strong winds with a significant surf... track angles for the 250 can become 120-135 degrees or more.<hr height="1" noshade id="quote"></blockquote id="quote">

What kind of angles can you attain in 7-8 knots and flat water?

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Tony Partain
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Response Posted - 06/10/2004 : 17:21:44

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Keep in mind for example that the high freeboard, light displacement, and large sail plan all contribute to increasing tacking angles with increasing winds.<hr height="1" noshade id="quote"></blockquote id="quote">

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Generally, as boat speed increases, the apparent wind increases. As actual or apparent wind increases, the boat's ability to point to weather increases<hr height="1" noshade id="quote"></blockquote id="quote">

Which is it? More wind point higher or more wind and point lower? I would assume that up to a certain point the boat will point higher and then the wind resistance on the freeboard would over come the pointing ability and cause you to lose pointing ability. Also what will the efect of being over powered?

Edited by - Tony Partain on 06/10/2004 17:23:39

Derek Crawford
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Response Posted - 06/10/2004 : 19:01:03

Tony - I'm with Steve on this one. I don't know about C250's, but on our C25 the tacking angle in light air is 90 degrees. As the wind picks up above 10k that angle decreases to close to 80. When overpowered, if you start to round up you just use it as a chance to get further to weather

(and then you shorten sail

)
Derek

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Steve Milby
Past Commodore

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Response Posted - 06/10/2004 : 20:53:55

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Which is it? More wind point higher or more wind and point lower? <hr height="1" noshade id="quote"></blockquote id="quote"> It's both. In moderate winds and smooth seas, an increase in windspeed enables a sailboat to point higher. But, the only power that drives the boat is the power that is generated by the sails. As the windspeed increases further, the amount of power generated by the sails does not increase. In fact, you eventually have to reduce sail area to keep from overpowering the boat. You have to use this fixed amount of power to push the boat against the combined and increasing forces of the wind on the boat's windward freeboard and the waves smashing against it's windward bow. Those forces cause the boat's course to drift off downwind. The principle that "more wind lets the boat point higher" is only valid until the forces of the wind and the seas overcome it.

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Also what will the efect of being over powered?<hr height="1" noshade id="quote"></blockquote id="quote"> When you're overpowered, the boat heels excessively, and that increases drag, which decreases boatspeed. All of that reduces the boat's ability to claw to windward. In a survival storm, there's a point at which even storm sails can no longer produce enough power to overcome the forces of the wind and waves, and the boat is no longer able to carry on sailing. When that happens you have to resort to other tactics, such as streaming a drogue.

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Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 06/10/2004 : 21:53:28

Tony
buy this and tell us.
http://www.sailgb.com/sshop/prod_info.asp?PID=733

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Tony Partain
1st Mate

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USA
93 Posts

Response Posted - 06/10/2004 : 22:16:14

Steve I believe that you have pinned the tail on the donkey. Your explanation and reasoning are spot on. I my experience with the C250 (I have only owned one for three months) is that in light to moderate winds my tacking angle starts out just under 90 degrees and decreases to the mid eighty's when the wind pipes up. These numbers are from GPS tracks. I have found the GPS to be a great tool.

Now the next question. When sailing in heavy weather under mail only (I haven't tried this yet with the GPS) will the boat point as high or not? Also what effect will reefing the main have on pointing? I was out in 25+ knots with the main only reefed (tallrig)and was pleased how the boat responded, it was quite docile yet seem to be moving close hull speed.

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Frank Hopper
Past Commodore

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Pitcairn Island
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Response Posted - 06/10/2004 : 22:37:03

Tony, my suggestion to buy the Silva compass was not flippant. Your boat will seldom have the same performance day to day do to the wind; as you already realize the sail plan and choice of sail has a huge affect. (Chop and wave action will affect you too.) It sounds like this is something that you want to be conscious of as you sail your boat and to have accurate data you will need a real time analog device, the deck mount compass I have suggested is the cheapest solution I know of, I used one for years on another boat. Another short term data point can be had if you race against a J-24 and ask them keep track of how high they point then try to follow them for a while and get a feel for how much higher they point than you. For me I watch the Windex, after a while you recognize the days you are pointing high and the days you are not, after all the real "possible" number is academic, the question is how are you sailing today!

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Tony Partain
1st Mate

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Response Posted - 06/10/2004 : 22:50:58

Thanks for the suggestion, its quite valid I use my compass every time sail. I use the Windex also and depending on the conditions the arrow will be inside or outside of the mark. Today I am not sailing and will not be sailing for a few days. I will be bottom painting my boat this weekend. Let the fun begin!!!

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Steve Milby
Past Commodore

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Response Posted - 06/10/2004 : 23:57:44

<blockquote id="quote">quote:<hr height="1" noshade id="quote">When sailing in heavy weather under mainsail only (I haven't tried this yet with the GPS) will the boat point as high or not?<hr height="1" noshade id="quote"></blockquote id="quote"> A boat will point fairly well under mainsail alone, but, on average, I don’t think it will point as high as it will with a balanced sail plan. I’ve never experimented with it, but the history of Gary Hoyt’s Freedom line of boats suggests that to be the case. The Freedom was originally designed and built with a huge mainsail on an unstayed mast, and no jib. They were considered very fast off the wind, but they couldn’t point to windward. Eventually, the designer figured out a way to attach a small jib, and the jib significantly improved their windward ability.

<blockquote id="quote">quote:<hr height="1" noshade id="quote">what effect will reefing the main have on pointing?<hr height="1" noshade id="quote"></blockquote id="quote"> Reefing the mainsail not only reduces its area, but it also reduces the depth of the sail’s draft. In high winds, both of those things help the boat point to windward (assuming you’re flying the optimum amount of sail without being overpowered).

Edited by - on

mday
Navigator

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197 Posts

Response Posted - 06/11/2004 : 01:06:16

I agree with Steve. Even with a reefed main, I've found flying a little jib seems to help pointing (and handling), so I always try to keep a bit a jib unfurled. If it's gusty, you don't need or want much. This is just from experience sailing my C250 WB in various conditions.

Max

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Tony Partain
1st Mate

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93 Posts

Response Posted - 06/11/2004 : 10:12:34

Max how is the sailing on Lake Pleasant? I came very close to moving to the area in 1999. Lake Pleasant looked like a great place to sail with very nice facalities.

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Arlyn Stewart
Master Marine Consultant

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2980 Posts

Response Posted - 06/11/2004 : 10:31:16

Derek, the tack angle also decreases on the 250 with increasing winds...but the weather track falls off badly with increasing winds... Tony's question seemed to be about weathering ability with equates to track not tack angle.

I'm would speculate that the C25 with fin, its skeg, greater weight would resist leeway better than a 250. From what we have seen of the heads up racing between the two... we look back at the '98 nationals which were in light air and the 250 reeled in the 25s which had a five minute head start... but when the winds increased...250 advantages disapeared.

The 250 can suffer a LOT of leeway when weathering... avoiding pinching is a must as well as weather helm angles of 3-4 degrees on the rudder trim... as Steve mentioned boat trim is huge... because if the weather helm exceeds those numbers, rudder drag will eat up any weathering efficiency.

Weathering ability in greater winds requries a tight rig to minimize sail drag.

Tony is right...rig tune and sail trim are huge. However... to set the boat up for strong wind weathering... will make it a dog in light air sailing. Nothing much new here. When I raced Hobies... the rig was tuned for differing conditions... if this wasn't done... one just wasn't compeditive.

The big problem on the 250... is the "stinking" B&R rig which basically renders a back stay adjuster mute, hence the rig has to be set for only one condition..... You c25 guys have a huge advantage here... as you can tune your rig on the fly with the backstay tensioner. Of course... I know that you know that most c25 owners tune their rigs far too tight and don't get the benefit of a backstay adjuster... they might just as well take if off the boat. The compeditive c25 racer will have a very loose rig... and know when to use the tensioner to alter the rig to a tight settup.

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Steve Milby
Past Commodore

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Response Posted - 06/11/2004 : 11:29:09

<blockquote id="quote">quote:<hr height="1" noshade id="quote">The compeditive c25 racer will have a very loose rig... and know when to use the tensioner to alter the rig to a tight settup.<hr height="1" noshade id="quote"></blockquote id="quote"> Arlyn, for years I raced with a tightly adjusted rig, and, as you said, wasted my backstay adjuster. Thanks to Derek, I learned how to adjust the rig correctly (and loooosely). Initially, I tensioned the backstay adjuster when beating to windward, and left it like that all the way along the windward leg of the course. I only eased it after I rounded the windward mark. Now I "power up" and "power down" with the puffs and lulls. When a puff comes along that is so strong that the boat is becoming overpowered, I add tension to the backstay, outhaul and cunningham. The effect is to depower the sails and keep the boat on her feet much longer. In the lulls, I ease all those controls, even though we're still on the windward leg. By doing that, you increase the percentage of time that the sails are generating maximum power, and you reduce the percentage of time that the boat is overpowered.

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Tony Partain
1st Mate

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Response Posted - 06/11/2004 : 12:16:07

<blockquote id="quote">quote:<hr height="1" noshade id="quote">The tack angle also decreases on the 250 with increasing winds...but the weather track falls off badly with increasing winds.<hr height="1" noshade id="quote"></blockquote id="quote">

This is one of the things that I was wondering about but didn't articulate it properly. I seemed in higher winds going to weather would result in more leeway. After about 12-15 knots is when this seems to be a factor. So reducing sail, flatting sail and lowering the traveler to combat over powering plus a tight rig is about all I can think of to help in this situation. Pinching to reduce heel didn't seem to work as well as it did on the Hobie's.

<blockquote id="quote">quote:<hr height="1" noshade id="quote">The big problem on the 250... is the "stinking" B&R rig which basically renders a back stay adjuster mute, hence the rig has to be set for only one condition.....
<hr height="1" noshade id="quote"></blockquote id="quote">

But will a backstay adjuster provide any tuning benefits?

With this said how should the backstay with out an adjuster be set in relation to the rest of the rig?

Edited by - on

Arlyn Stewart
Master Marine Consultant

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Response Posted - 06/11/2004 : 15:46:43

Tony, my thought is that one of the most important aspects of weathering is to fight off drag. The two places it is produced the greatest is the thickness of the foil section of the sails and the attack angle of the keel and rudder.

As Steve just said, he has learned to constantly adust the foil thickness to the wind condition. In increasing wind, less foil not only means less heel but also less drag. In light air, more power is needed so a thicker foil is needed and at slow speeds, the drag is not a very big issue for the sailplan. There are some who argue that in extremely zepher winds, that a thin foil can be more beneficial. Quite frankly, my sensitivity in zephers isn't acute enough to tell.

There are a few of us who run a backstay tensioner on the 250... but it can be a risk. In high winds, employing the backstay tensioner to get the desired tight rig... will leave the leeward shrouds flopping and I mean litterally flopping around. This is thought to be unsafe because sudden shifts of loading shock the slack shrouds and might cause failure. Also, the mast is not supported at the spreader section when using a backstay tensioner on a B&R rig. This leaves the door open to mast pumping and severe mast pumping can fatigue the mast, some argue rather quickly.

There is a way to overcome the B&R rig (rig with radical raked spreaders and no forward lower shrouds) and use a backstay tensioner. It is to use a baby stay and I do use one... but I'm a cruiser, no day sailor or racer would want to deal with one.

I've discussed the use of a backstay tensioner with Bryan Beamer who uses one and who doesn't use a baby stay. The tensioner is effective in reducing the headsail slack and firming up the jib for breezy conditions while allowing a looser rig for light air work. His rig settings obviously weren't bad as he won last years Nationals. Just remember, its use creates a loose mid mast. That I know of... I've never heard however any reports of severe mast pumping on the 250... but... not many 250s have been set up loose either.... because to do so, will have them grossly overpowered when the breeze blows.

Catalina ain't going to recomend it because simply put, more mast failures have probably happened because of loose rigs than firm ones.

The backstay on the 250 is almost redundant. Many B&R rigs skip the backstay. Adjust it last and adjust it only to clear the batten strips and roach. Firming it too much will loosen the force of the upper shrouds as they push the spreader forward and hold the middle mast section prebend.

All most forgot... the other weathering drag issue is the attack angle of the keel and rudder. Lift to drag ratio is ideal at 3-4 degrees. The 250 can suffer severe weather helm when heeling too far. I've tried to outline why I think that happens on my web site. Severe weather helm requires far too much attack angle (drag) on the rudder. Trim the boat so that the optimum of 3-4 degrees is achieved... mindful that much is as great of a requirement as too much is a liability. No weather helm going to weather would be very inefficient as a great deal of lift is thrown away.

Last... keep the boat within 10-15 degrees of heel. This in my opinion not only makes the sails more efficient... but I argue that heeling a hull such as that on a 250, actually creates hydro lift forces to leeward and is very counterprouductive to weathering. It is also the same lift forces to leeward that cause increasing weather helm beyond the good 3-4 degrees.

When weathering...note where the tiller is. If it is at more than 3-4 degrees... effieciency is being lost, if it is less than that... there is no efficiency as the rudder and keel are not lifting windward.

Edited by - on

Tony Partain
1st Mate

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USA
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Response Posted - 06/11/2004 : 19:33:05

Arlyn thanks for the reply I will respond tomorrow. Everybody have a good weekend I need to go pick up the boat and bottom paint.

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Tony Partain
1st Mate

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Response Posted - 06/14/2004 : 00:14:17

<blockquote id="quote">quote:<hr height="1" noshade id="quote">A boat will point fairly well under mainsail alone, but, on average, I don’t think it will point as high as it will with a balanced sail plan<hr height="1" noshade id="quote"></blockquote id="quote">

What would be the best combination of main and jib for pointing ability? Larger jib and reefed main or smaller jib and no reef? I have what I feel is the correct amount of weather helm. Would running a larger jib and reefed main lead to better pointing?

BTW the bottom paint is almost done, just need to lower the four corner bunks, prime and paint and I am done. Should get two done tomorrow and two on Tuesday, slpash on Wednesday.

Edited by - on

Arlyn Stewart
Master Marine Consultant

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Response Posted - 06/14/2004 : 07:31:39

The fastest I've had my boat going was with full main and two turns of reef on the 110 jib. It maintained 7.3 knots (1.1 knots above hull speed) for several hours. When the wind increased a bit more, the first reef in the main was took, the jib let out and speed fell to 6.2 knots (hull speed). Nothing I could do under reefed main would coax it back above hull speed.

Breaking hull speed takes a lot of effort... its normally thought that to do so, the jib has to supercharge the main. This used to be called the slot effect, named because an overlapping jib was brought in close to the main and formed a tight ventura for the air to compress and then rush thru at higher speeds and thus cause an extraordinary lift of the main.

The slot effect has been debunked in that we know that the overlapping is not neccessary... but the principle of the jib working in conjunction with the main is well understood. Some argue that the jib if set so that it appears that the main and jib are one large sail offers the best speed ability, others still think its the way a jib even if it doesn't overlap, feeds accelerated air over the back of the main causing the main to superpower.

Some of the problem is thought to be the leading edge of the main's foil which is the mast. If that poor leading edge can be taken out of the equation by presenting the jib and the main as one sail, then big dividends are achieved. I've never heard of a 250 breaking hull speed under main alone, so the theory of the poor leading edge is a good one.

Interestingly, Roger McGregor uses a rotating mast similar to what is used on Catamarans on his newest 26. With a rotating mast, the mast is able to be positioned so that its thinner section is aligned with the foil and thus reduces the turbulence of the air and provides a better flow over the back of the main. While I'm not sure a Mac 26 can be turned into a hot rod... the rotating mast on a catamaran was an enhancement.

At any rate, the go fast condition cannot be achieved with a headsail that is sagging off on a loose forestay. While some of this may have to do with the foil thickness of the headsail(too much drag), I believe that it takes a firm headsail to join in proper relationship to the main and present the slot effect, elimination of the mast issue, one sail image or whatever is happening to create what most sailors discover sooner or later... a power charged condition.

Edited by - on

Tony Partain
1st Mate

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Response Posted - 06/14/2004 : 12:01:46

After reading your last post, one could assume that the jib position and shape are the utmost of importance. Even with a main that has some miles on it, one would benefit from a new jib. The fastest I have had my mine on the gps was 6.7 knots (this was before bottom paint and had quite of growth on the hull) with a full main and the 150. The 150 is the newest sail in the group and it stands to reason that the better shape and over lap contributed to the speed I had attained in a relatively low wind condition.

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