Association Forum - Rig Tuning

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Rig Tuning

New Topic

Topic Locked

Printer Friendly

Author

Topic

jerlim
Master Marine Consultant

Member Avatar

USA
1484 Posts

Initially Posted - 04/04/2010 : 20:22:08

Much has been written about tension, adjustments and preferences, but what about waiting a bit once the boat is off the hard and splashed to tune the rig? I understand how/why the hull shape changes a bit while sitting on stands and relaxes when it's supported by water to it's natural contour. I can't find any info regarding how long she should float until she returns to her natural shape and it's OK to tune the rig...any thoughts??

(oh yes...we splashed on Friday

! ! )

Jerry

Edited by - on

JohnP
Master Marine Consultant

Members Avatar

1520 Posts

Response Posted - 04/05/2010 : 05:06:57

My guess is that it would take about 1 full minute for the stresses to equilibrate and the fiberglass hull to take its normal shape afloat.

The temperature may have more effect on the stay tension, but it would stretch or shrink each cable about the same amount. It makes sense to tune the rigging afloat.

So, when are you heading off to <s>Montauk</s>, no I mean <s>Block Is.</s>, I mean <s>Martha's Vineyard</s>, your next great maritime adventure?

Happy sailing!

Edited by - on

Steve Milby
Past Commodore

Members Avatar

USA
5909 Posts

Response Posted - 04/05/2010 : 06:39:01

With my C25, I considered rig tuning an ongoing process. You rarely get it tuned exactly right the first time you try, so you have to make adjustments occasionally. I would suggest you tune it when you launch, and then fine tune it as needed.

If I thought my boat was significantly out of shape because of the way it was supported by jackstands, I'd be annoyed at the guy who setup the jackstands. Jackstands should support the boat without significantly distorting the hull.

Edited by - on

JimB517
Past Commodore

Members Avatar

USA
3285 Posts

Response Posted - 04/05/2010 : 09:39:45

Always recheck after the first sail in decent wind.

I had a real expensive loos guage and I found a significant difference in tension just from having the topping lift on. I took it off and had to retune. Then I doscovered the spin halyard was still clipped on the pulpit. I took that off and had to retune.

Edited by - on

Dave5041
Former Mainsheet Editor

Members Avatar

USA
3758 Posts

Response Posted - 04/05/2010 : 12:01:11

You can get wacked out on this stuff. The boat gets longer and wider and the mast gets taller at a faster rate than the SS rigging lengthens as the temperature goes up.

Glad I'm not a racer.

Edited by - on

Derek Crawford
Master Marine Consultant

Members Avatar

USA
3323 Posts

Response Posted - 04/05/2010 : 16:09:19

Jim, I always tune the rig with it detensioned - backstay, vang, and mainsheet all slack.

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5430 Posts

Response Posted - 04/05/2010 : 19:37:10

Derek - do you always use the Loos meter? Is there any suitable substitution other than listening for the "twang" of the stay?

Edited by - on

Stu Jackson C34
Admiral

Members Avatar

844 Posts

Response Posted - 04/05/2010 : 22:56:43

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Voyager
 Is there any suitable substitution other than listening for the "twang" of the stay?
<hr height="1" noshade id="quote"></blockquote id="quote">

Yes. The Catalina manual actually has a quite excellent tuning guide. It's used for all masthead Catalina Yachts and works very well.

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 04/06/2010 : 06:32:38

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Voyager
 Derek - do you always use the Loos meter? Is there any suitable substitution other than listening for the "twang" of the stay?
<hr height="1" noshade id="quote"></blockquote id="quote">Derek's rig doesn't "twang"--it just "rumbles".

Right, Derek?

Edited by - Dave Bristle on 04/06/2010 06:33:24

Derek Crawford
Master Marine Consultant

Members Avatar

USA
3323 Posts

Response Posted - 04/06/2010 : 07:51:29

Yes, I do use a Loos guage (just the initial reading from the front, I don't translate the readings into lbs of tension).
The current readings are: aft lowers - 20, mainstays - 32, forward lowers 25. The forestay has 8-10" of sag and the backstay will move freely about 12".
This is a very loose rig but we don't have to deal with wave action and it is FAST off the wind and no slouch going to weather.

Edited by - on

Voyager
Master Marine Consultant

Members Avatar

USA
5430 Posts

Response Posted - 04/06/2010 : 18:43:52

I wondered about my backstay because it was quite loose - 12" would not be a surprise. I tweaked it a little tighter, and will re-read the specs in the manual and the doc: tuning the C-25.

Edited by - on

JimB517
Past Commodore

Members Avatar

USA
3285 Posts

Response Posted - 04/07/2010 : 09:43:05

When I talk about using the Milby/Crawford method, I set the rigging up using Milby's guide, then tension the wires according to Crawford's numbers above.

This results in a very loose rig.

My boat has nearly perfect balance in light to medium air - you can let go of the tiller and she'll steer mostly by herself.

You can tune lee helm/weather helm with the backstay adjuster while sailing. With the backstay adjuster fully on the mast is bent quite a bit and the forestay tension on the Loos guage comes up in the 45 range.

My boat is fast and competitive off the wind and I need better pointing. The inner jib car tracks help quite a bit with that.

So would a new 155 mylar/laminate racing jib but that is a little too much $ right now!

Edited by - on

Derek Crawford
Master Marine Consultant

Members Avatar

USA
3323 Posts

Response Posted - 04/07/2010 : 10:04:07

Jim, with all due respect I believe that you would be faster with a new main rather than a new jib. It looks as though your main is the original Catalina triangle. If you had one with a big roach you'd add 20-30 sq.ft more sail area (my leech extends a good 2" aft of the backstay). And this should not affect your PHRF and it is within our class rules.

Edited by - on

JimB517
Past Commodore

Members Avatar

USA
3285 Posts

Response Posted - 04/07/2010 : 11:24:07

I have the Ulman full batten, loose footed main. It is 1 year old. It has already stretched quite a bit (I am a little dissapointed it stretched so soon, but then I have sailed about 250 days on it).

Here is a pretty good shot of my boat in racing trim in about 15 - 20 knots.

You can see the new main, we were busy sheeting in the jib.

My racing jibs are hand-me-down mylar/laminate/carbon fiber jibs from a Merit 25. They were 2 seasons old when I got them. The jib from a Merit 25 is about a 145% on my boat. It is also not a deck sweeper. So I am giving up some significant square footage with that sail. The Merit #2 is about a 125% on my boat. The price was right (free for the taking). I converted them to hank on and put my numbers on.

I have dacron 155, 135 jibs in really good condition. I use the dacron jib on race day if the wind is really light.

Here you can see us off the wind, passing a Cape Dory 26.

The biggest issue racing is that I can pass the Catalina 27s and Catalina 30s down wind. Up wind I get rolled and out pointed. The local guy in the 27 has all new mylar/laminate sails (jib and main).

Edited by - on

HeelinPatrick
Navigator

Members Avatar

USA
102 Posts

Response Posted - 05/24/2010 : 10:28:40

I've read the tuning write ups and all, but have a question on how to keep the aft lowers loose. When I tuned mine, I needed to have a fair amount of tension on the aft lowers to keep the mast in column. The problem is, the front lowers I think are over tensioned as a result when I crank on the back stay. Just yesterday, 5 strands on the one lower broke, and had to order a new set.

Any tips on having 'loose' aft lowers? Also, when I do crank on the backstay, the mast seems to stay strait in the lower half, then curves backward on in the upper half. I had envisioned a gental curve in the entire mast, rather than the top half bending back.

And any total deflection estimates, seems that the top of mast curves back about 2 to 3 inches with back stay on, compared to mast perfectly strait with back stay off.

Thanks for any help!!!

Edited by - on

HeelinPatrick
Navigator

Members Avatar

USA
102 Posts

Response Posted - 05/24/2010 : 10:30:57

I forgot to add too, I haven't built up the courage to do the uppers to 1" deflection with 50 lbs pull at shoulder. I'm thinking I'm closer to 2 or 3 inches when I give it a decent pull. I'm afraid of pulling the deck and bulkheads if I tighten down any more.

Edited by - on

PCP777
Master Marine Consultant

Members Avatar

USA
1225 Posts

Response Posted - 05/24/2010 : 11:48:02

How does one tighten a forestay that has the CDI Roller furler 4/6 on it. This weekend my forestay was wobbling so bad I abandoned my sailing trip.

Edited by - on

JimB517
Past Commodore

Members Avatar

USA
3285 Posts

Response Posted - 05/24/2010 : 12:06:18

loosen the forward lower shrouds.

tension the backstay turnbuckles

retighten the forward lower shrouds.

retighten the aft lower shrouds.

(both forward and aft lowers should be just past finger tight).

This will tilt the mast back.

Sail and check weather helm. Tilting the mast back increases weather helm.

Forestay should be real tight for best pointing.

Edited by - on

PCP777
Master Marine Consultant

Members Avatar

USA
1225 Posts

Response Posted - 05/24/2010 : 12:17:08

Thanks Jim!

Edited by - on

aeckhart
Master Marine Consultant

Members Avatar

USA
1709 Posts

Response Posted - 05/24/2010 : 13:20:05

Derek,

I too have the non-standard roach on my main. It's a screamer in light air but I find myself reefing earlier than I did with the standard main. Do you find this to be the case?

Edited by - on

HeelinPatrick
Navigator

Members Avatar

USA
102 Posts

Response Posted - 05/24/2010 : 14:46:14

Jim, I should have mentioned I have an adjustable backstay.

I'm thinking too, that following what you did, if you then let off the back stay tension, wouldn't the mast then bow forward (which I've heard isn't desirable).

When I tuned it the first time, I did the uppers, then with no tension on the fore or back stay, took slack and slightly tightened forward lowers, and even lighter tightened the aft lowers. Then when I would put on back stay tension, looking up the main track, you could see a S-curve (bottom half bowed to starboard, upper half bowed to port. Adding a fair amount of tension to the aft lowers seemed the only way to get rid of the S-curve, but then that just adds extra tension to the front lowers. And might be why the one front lower strands started to break.

I just don't want to smoke another pair of lowers, and make sure the rig is safely tuned.

Thanks for any input!

Edited by - on

PCP777
Master Marine Consultant

Members Avatar

USA
1225 Posts

Response Posted - 05/25/2010 : 06:31:27

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by JimB517
 loosen the forward lower shrouds.

tension the backstay turnbuckles

retighten the forward lower shrouds.

retighten the aft lower shrouds.

(both forward and aft lowers should be just past finger tight).

This will tilt the mast back.

Sail and check weather helm. Tilting the mast back increases weather helm.

Forestay should be real tight for best pointing.
<hr height="1" noshade id="quote"></blockquote id="quote">

I have an adjustable back stay as well, so how do I set it? 50%?

Edited by - on

jerlim
Master Marine Consultant

Members Avatar

USA
1484 Posts

Response Posted - 05/26/2010 : 17:58:30

I set all the other stays w/ the adjustable rig back stay as loose as it gets...and then build in a gentle mast curve...which can be increased when necessary by tightening down on the backstay.

Edited by - jerlim on 05/26/2010 18:03:29

Steve Milby
Past Commodore

Members Avatar

USA
5909 Posts

Response Posted - 05/27/2010 : 06:11:37

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by PCP777[i]I have an adjustable back stay as well, so how do I set it? 50%?
<hr height="1" noshade id="quote"></blockquote id="quote">
That depends on the direction you want to sail and the windspeed. If you're sailing to windward and in strong winds, then you should increase the tension on the backstay, so that you take the sag out of the forestay, thereby reducing the amount of power generated by the sails, especially the jib. If you want to sail off the wind, or in lighter air, then you should ease the tension on the backstay, to increase the amount of sag in the forestay, thereby increasing the amount of power generated by the sails.

The amount of tension that you apply should generally be proportionate to the strength of the wind. When sailing to windward in strong winds, the tension should be enough to remove almost all of the headstay sag. When sailing to windward in lighter air, the tension should eased until there is some noticeable headstay sag. The exact amount depends on the exact windspeed, but if you get it close to the correct amount of tension, you'll be much better off than the boats that don't have backstay adjusters.

Edited by - Steve Milby on 05/27/2010 06:18:05

PCP777
Master Marine Consultant

Members Avatar

USA
1225 Posts

Response Posted - 05/27/2010 : 07:33:17

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Steve Milby
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by PCP777[i]I have an adjustable back stay as well, so how do I set it? 50%?
<hr height="1" noshade id="quote"></blockquote id="quote">
That depends on the direction you want to sail and the windspeed. If you're sailing to windward and in strong winds, then you should increase the tension on the backstay, so that you take the sag out of the forestay, thereby reducing the amount of power generated by the sails, especially the jib. If you want to sail off the wind, or in lighter air, then you should ease the tension on the backstay, to increase the amount of sag in the forestay, thereby increasing the amount of power generated by the sails.

The amount of tension that you apply should generally be proportionate to the strength of the wind. When sailing to windward in strong winds, the tension should be enough to remove almost all of the headstay sag. When sailing to windward in lighter air, the tension should eased until there is some noticeable headstay sag. The exact amount depends on the exact windspeed, but if you get it close to the correct amount of tension, you'll be much better off than the boats that don't have backstay adjusters.
<hr height="1" noshade id="quote"></blockquote id="quote">

Thank you Steve.

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.