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Catalina 250 Specific Forum

Rounding up - is it my sail?

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britinusa
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Initially Posted - 08/03/2006 : 11:55:48

Just returned from our 7 day cruze to key largo florida.
The wind was pretty blustery on day 2, so we sailed with just the Jib and were able to reach all the way from Sands Key to Pumpkin Key.
The next day, still blustery, but not so heavy, we put up the main with 2 reefs in it. WOW! We had the best sail ever! no rounding up, nicely balanced, easy steering (wheel) even Peggy noted the amazing difference. (We have only put in a single reef previously, this was the first with double reef.)

To achieve the double reef, I tied a line from the 2nd Tack reef around the boom and moved the aft reefing line to the 2nd cringle. Not neat, but very effective.

Ok, so now the question!
Is it possible that the amount of rounding we have experienced previously is due to the Jib / Main sail area ratio?

ie. Would a 135 or 155 jib reduce the rounding.

(We had intended to install a 2nd water tank before we left, but the wrong size tank arrived and would not fit.)

The stern sits about 2-4" lower than the bow looking at the waterline.

So my theory is that if I put up a 135 Jib, then the ratio of jib to main will be higher and the balance restored similar to that achieved with the 110 jib and the full battened main.

Have any of you 250 owners compared balance with the different sized jibs?

Paul.

Joint Decision. (Sold)
PO C250WB 2005 Sail # 841.

Moved up to C34 Eximius

Updated August 2015

Edited by - on

Russ.Johnson
Commodore

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Response Posted - 08/03/2006 : 14:45:09

Hi Paul,
It's me again. I'm glad your trip went well.
I was wondering how the extra water tank would work (mine works pretty well).
It seems we have the same experiences about at the same time.
I'm glad you posted this topic, I was working on sail balancing last week.

I only have the 110% jib, but here's what I've found so far.
There the 3 situations I find most round-ups on my WB.

1 - Greater heel angle causing less rudder surface/control.
This has been discussed a lot with the shorter 3rd generation WB rudder.

2 - Sailing Broad Reach with following seas on the quarter (2-4ft).
This is caused by waves hitting the stern and rudder pushing the aft around.

3 - Sail Balance between Jib and Main (today's topic)
This happens to me when the boat is heeling 15 degrees (or less) and
sailing from close haul to beam reach.
I was able to reduce this problem with the following
Add more power to the jib and less power to the main.
Move the jib sheet cars all the way forward on the tracks.
Tighten the outhaul (to flatten the main).
Loosen the boom vang (to twist off, luff the top of the main).
Loosen the main sheet (so it will luff before the jib).
Reef the main if necessary (if the above isn't enough).

There are several posts about:
Pulling the centerboard aft to help the balance.
Tuning the mast and raking it aft.
I find the extra water tank helps, but after all the above have been checked.

I agree with you, sail balancing makes a big difference.
I would like to hear how others manage it.
What wind speed would you furl a 135% jib?

Russ (#793)

Edited by - on

welshoff
Captain

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Response Posted - 08/03/2006 : 15:46:13

Paul,
I have a 135% on my boat (wing keel), so not sure if it relates to a water ballest?

When the wind gets "blustery", I usually roll up the 135% to about a 110% to 100%. I find this gives me a better control over the boat. Then as Russ stated, I flatten the main/loosen boom vang to depower it then adjust the jib as Russ said to put more power into it via the lead angle on the jib sheet. I then "play" the main on the bigger wind gusts to help keep the boat flat.

If the wind continues to "push" me around, I then will put a reef in the main. Most of our power comes from the main sail and I adjust the head sail to balance out the main first. On windy days I think the 135% adds to the round ups and I usually get a little more control when I reduce it's size first. Then move on to the main and make the above adjustments. My 135% works best for me on lighter wind days and I need the extra "pull" to get a little more speed out of the boat.

Note: my boat also has better balance since I added weight to the bow to put her on her lines and then adjusted mast rake and rigging tensions.

Edited by - on

britinusa
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Response Posted - 08/03/2006 : 16:31:52

Russ,
<blockquote id="quote">quote:<hr height="1" noshade id="quote">1 - Greater heel angle causing less rudder surface/control.
This has been discussed a lot with the shorter 3rd generation WB rudder.<hr height="1" noshade id="quote"></blockquote id="quote">
I avoid this issue by keeping the boat on an even keel as per the admirals memo!

<blockquote id="quote">quote:<hr height="1" noshade id="quote">2 - Sailing Broad Reach with following seas on the quarter (2-4ft).
This is caused by waves hitting the stern and rudder pushing the aft around.<hr height="1" noshade id="quote"></blockquote id="quote">
This is a common situtation. The stern down condition most likely worsens the roundup, so I hope that adding the additional water tank will help that (at least while it has water!)

<blockquote id="quote">quote:<hr height="1" noshade id="quote">3 - Sail Balance between Jib and Main (today's topic)
This happens to me when the boat is heeling 15 degrees (or less) and
sailing from close haul to beam reach.
I was able to reduce this problem with the following
Add more power to the jib and less power to the main.
Move the jib sheet cars all the way forward on the tracks.
Tighten the outhaul (to flatten the main).
Loosen the boom vang (to twist off, luff the top of the main).
Loosen the main sheet (so it will luff before the jib).
Reef the main if necessary (if the above isn't enough).<hr height="1" noshade id="quote"></blockquote id="quote">

This is the stuff that is not so clear for me. (How I would have loved to go to the nationals this year and get the benefit of our very experienced sailors to explain this.)

My problem is probably best descibed as 'confused', folks talking about flatening, twisting, powering, depowering, etc. I read plenty of online articles on the subject, but have yet to find a clear and consise discription of all these terms. (I don't mind admiting it as I know once I get it then life will be good

)

Back to the observation that I was able to balance the boat without issue after putting in a double reef. I would occur to me that using a larger jib would balance out with the unreefed main.

One day I'm going to slap myself on the forehead when I figure this out.

Paul

Edited by - on

aeckhart
Master Marine Consultant

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Response Posted - 08/08/2006 : 07:26:58

Paul,

There are a number of books and articles on this subject but the best I've ever found to explain sail trim is the North U. sail trim course. It comes as two paper back books or books with CDs. The cost is not prohibitive for the books and they are pretty well illustrated. You will find them on any North Sails web site.

Edited by - on

dlucier
Master Marine Consultant

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7583 Posts

Response Posted - 08/08/2006 : 08:50:00

Paul,

For some info on sail trim, go to the article link at SailNet and do a search on "Mainsail Trim", "Headsail Trim", or something similar. You should find some good info.

[url="http://www.sailnet.com/collections/articles/index.cfm"]SailNet Articles[/url]

Edited by - on

britinusa
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Response Posted - 08/08/2006 : 19:56:01

Thanks Guys,
Al, are you referring to 'North U. TRIM CD Rom' that is available from [url="http://www.cruisingdirect.com/cd/CD_catalog.taf?_function=list&category=12"]sailnet[/url]

Paul

Edited by - on

britinusa
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Response Posted - 08/13/2006 : 08:57:43

I found a great resource for help with Sail trim.
"The Complete Sailor, learning the art of sailing" by David Seidman.

We (the admiral and I) have been working our way through the segments on Sails and Sail Controls.

My original question was <blockquote id="quote">quote:<hr height="1" noshade id="quote">Is it possible that the amount of rounding we have experienced previously is due to the Jib / Main sail area ratio?
<hr height="1" noshade id="quote"></blockquote id="quote">

And after reading, absorbing and hopefully understanding, it would seem that is the case.

Here's my translation of the situation.

With full main and 110 jib, we experience substantial rounding.
the contributing factors appear to be...
a) CLR (center of lateral resistance) is moved aft when the stern is lower than the bow. This is now easy to understand: The boat is designed with the CLR just about the center of the drop keel, perhaps a little aft of that. So when the boat is stern heavy, then the bow is higher, the stern is lower so the CLR is effectivly moved aft.

b) CE (center of effort on sail plan). It's reasonable to assume that under just the jib the CE is mostly forward, and under just main it is mostly aft of the CLR. The more jib displayed to the wind the more forward the CE, and if the jib is fully deployed and the main is reefed and the weather helm is less, then the sail plan is in better balance. That translates to the CE is nearer to the correct location of just aft of the CLR.

Of course there are other factors that move the CE, mast rake, prebend, and sail tensions all affect the CE.

Sooooo, on our next trip we are going to correct the CLR by adding weight forward, we're going to check the mast rake (if the wind is light enough not to blow the topping lift around so we can use it as a plumb.) And we'll be spending time triming the sails.

Going to be fun!

Out of interest, who's using a larger jib than the 110%?

Paul.

Edited by - on

Bill Holcomb
Admiral

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Response Posted - 08/13/2006 : 09:35:41

Hi Paul,

It sounds like you had a neat trip and an educational one too.

The condition where your boat rounds up hard is often called "weatherhelm". A few years ago, I wrote an article for the Mainsheet magazine regarding weatherhelm and it's been added to the website in the Tech Tips section. The article might shed some light on the subject.
http://www.catalina-capri-25s.org/tech/snkhelm.asp

On your C250, there might even be a bit more of a tendency toward weatherhelm since the design team at Catalina made the decision to place the mast so much farther forward on the boat when compared to the C25. Your sail area is about the same area as a standard rig C25. But the relative size of the sails is very different. The difference shows up most strikingly when you look at the "J" and "E" measurements. "J" is essentially the foredeck measurement from stem fitting to the front edge of the mast: while the "E" measurement is the length of the mainsail foot.

On the C250 the "J" = 9' and the "E" = 11'
On the C25 the "J" = 10' 6" and the "E" = 9' 7"

This means that you have a much larger mainsail and a much smaller jib sail as compared to a standard rig C25. AND, your larger mainsail will tend to be a big weathervane that wants to spin your boat so that the bow points upwind. Additionally, your smaller jib size doesn't balance and counteract the main as effectively as on a more balanced sailplan. For instance, a C25 110 jib would be about a 135 or 140 on your boat.

My thought has been that double reef points on the C250 mainsail would be pretty important ever since the design first came out......Just like having double reef points on the tall rig C25 mainsail. Snickerdoodle's tall rig exhibits considerable rounding in winds as light as 14 or 15 knots if I don't tuck in a reef. And the second reef is needed when the breeze gets up in the 25 to 30 knot range.

Why did Catalina change the sailplan? By moving the mast forward, the designers could open up the interior substantially. So, the C250, C270 both have much larger mainsails and significantly smaller jibsails than the original C25 and C27.....and roomier interiors.

Bill Holcomb - C25 Snickerdoodle #4839

Edited by - on

britinusa
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Response Posted - 08/13/2006 : 10:10:33

Bill, your explaination follows my new understanding. I must admit, when we purchased the boat, we had the choice of a 110% or 160% jib, now wish I had taken the 160%.

However, peggy feels more comfortable when we are balanced for level sailing, so we're ok with the reefed main and full 110jib. If I see a 160 jib going cheap I'll consider snapping it up.

Paul.

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reuben
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Response Posted - 08/13/2006 : 18:44:32

We have the 135 jib, and it's great: plenty of canvas for winds up to fifteen mph, furl to about 110 at fifteen, tuck a reef in the main at 20 and sail in comfort all day.

Rather than a 160, Paul, you might consider an asymmetrical, which is (I think) about a 180. You can't go to windward with it, but the broad reach is stunning, and it's easy to rig with a sock using the jib halyard and an ATN Tacker.

We did learn, a few days ago, that the chute is too much sail for 15 mph winds. But in lighter winds it's a quick way to hull speed, and Catalina makes them in beautiful colors.

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frog0911
Master Marine Consultant

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Response Posted - 08/13/2006 : 22:32:38

I would disagree that the second hole in the headboard has no function. Its main function is to prevent the headboard sail slug from tearing out if reefed in high winds. Not my analysis, but from an article from sailnet which has to do with reefing. Here is the link. http://www.sailmaker.com/articles/reefing.htm Go down to the bottom under "Key Items To Look For" third bullet.

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Arlyn Stewart
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Response Posted - 08/23/2006 : 17:08:23

The simple answer is that if the rounding up that you have experienced was at lower heeling angles, then yes... it was likely due to sail balance.

However, if the rounding up was at greater than 30 degrees, it was likely do to the addition of hull lift imbalance to the other issues that have been mentioned.

Double reefing the main goes a very long way to keeping a 250 on her feet and away from the hull lift issues that come on with excessive heeling.

Interestingly, when equipped with the 1st generation rudder, a 250 w/b with 110 showing only would round up when overpressed... proof that sail balance is not the only or even perhaps the primary issue of 250 hard mouthed character.

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britinusa
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Response Posted - 08/23/2006 : 20:29:23

Arlyn, If I took the boat to 30d of heel I would be needing a good divorce attorney

Paul

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Arlyn Stewart
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Response Posted - 08/24/2006 : 06:55:50

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