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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

tuning standing rigging

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awetmore
Master Marine Consultant

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USA
1144 Posts

Initially Posted - 04/08/2012 : 19:25:58

I tried to follow the instructions in the pre-1998 C-25 manual today to adjust my standing rigging.

The manual calls for the lower shrouds to be not slack, but not tensioned. I can't get them close to that slack without loosening the turnbuckles so far that the cotter pins won't get back into them. This is especially true for the aft lower shrouds. I made a plumb bob and verified that my mast is not tilting forward.

Does this mean that I need a new T-bolt or turnbuckle body that is longer? Are they even available in different lengths?

I believe that the rigging on my boat is original (the PO's family has owned the boat since new, and he said that the mast had never been down) so it should probably be replaced at some point. However it also appears to be in pretty good condition and there are other places that I'd prefer to spend money.

I'll have the mast down in a week or two, which will be a good time to retune the standing rigging and replace portions if necessary.

thanks,
alex

Alex W
Seattle, WA
Express 37 "re-Quest"
previously owned 1984 Catalina 25 "Lutra"

Edited by - on

jerlim
Master Marine Consultant

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USA
1484 Posts

Response Posted - 04/08/2012 : 19:47:55

Alex - check the TECH TIPS section, especially the article by Bill Holcomb for details on the various degrees of tension per cable...in short all cables require a certain amount of tension. We prefer a stiff rig, while others may not want as much, after a point it is preference, but there are basic directions that apply to all C25s.

Edited by - on

awetmore
Master Marine Consultant

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USA
1144 Posts

Response Posted - 04/08/2012 : 20:02:03

Thanks. I hadn't read that article, although I had searched and read many threads in the archives. Most people seemed to recommend following the C-25 manual, and that is where I found the instructions that say:

[quote="C-25 manual"]
The lower shrouds (4 of them) should be adjusted so that they are looser than the upper shrouds.
While at the dock they should have no slack but also have no tension on them. No lower shroud when
pushed should deflect the mast more than any other shroud when pushed equally hard. If this can't be
achieved, the upper shrouds are too tight. Back off one-half turn at a time on the upper shroud
turnbuckles until the tension on the lower shrouds is brought into balance.
[/quote]

Reading Bill's instructions I'm guessing that my fore and back stays are a bit too slack. Fixing that first may allow everything else to come into shape.

Edited by - on

Steve Milby
Past Commodore

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USA
5902 Posts

Response Posted - 04/08/2012 : 20:10:51

From your description, something doesn't sound right, but we can't know if your hardware has been changed by the previous owner. Close-up photos of the turnbuckles on both sides might help.

Edited by - on

awetmore
Master Marine Consultant

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USA
1144 Posts

Response Posted - 04/08/2012 : 20:57:54

I can take photos when I'm down there this week.

They are chromed bronze open body turnbuckles that look just like the ones that Catalina Direct sells. The shroud and T-bolt are inserted the same amount, they just enter by about 3 threads per side past the turnbuckle body when tuned as in the manual (or how I interpreted it) and that isn't enough to run a cotter ring through the securing hole. The same style of turnbuckles are used on all 8 lines of the standing rigging.

I'll recheck it all per Bill's instructions.

Edited by - on

GaryB
Master Marine Consultant

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USA
4304 Posts

Response Posted - 04/08/2012 : 21:03:09

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by awetmore
 
...[quote="C-25 manual"]
The lower shrouds (4 of them) should be adjusted so that they are looser than the upper shrouds.

looser - not loose

While at the dock they should have no slack but also have no tension on them. No lower shroud when pushed should deflect the mast more than any other shroud when pushed equally hard. If this can't be
achieved, the upper shrouds are too tight.

I'm not sure exactly what the mean but I think this is basically stating that the lower shrouds should be equally tensioned. If the uppers are too tight the mast may have a bow side to side and/or fore to aft that would make it difficult to get the mast to deflect evenly on all shrouds when you push on them equally hard. One side would be looser and one side would be tighter or the foward lower on one side might be tight while the forward lower on the other side is loose and the rear lower is tight. Many combinations are possible that would keep you from getting equal tension.

Back off one-half turn at a time on the upper shroud turnbuckles until the tension on the lower shrouds is brought into balance.

By backing off on the uppers it allows the mast to straighten and make it easier to get all the shrouds in balance.

When tuning it's important to get a little rearward rake in the mast and make sure it's not leaning to one side or that it doesn't have a curve to one side or the other when you sight up the mast (It should be plumb side to side and the mast track should be straight when you sight up the mast). <hr height="1" noshade id="quote"></blockquote id="quote">

Reading Bill's instructions I'm guessing that my fore and back stays are a bit too slack. Fixing that first may allow everything else to come into shape.
[/quote]

Edited by - on

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 04/08/2012 : 21:08:43

Alex,
I've got two Loos gauges you're welcome to borrow to adjust your shrouds with. I'm not sure what size the standing rigging is on a C-25, but it's got to be similar to a C-250.

Edited by - on

awetmore
Master Marine Consultant

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USA
1144 Posts

Response Posted - 04/08/2012 : 21:11:17

Thanks David, that would be great. I'll shoot you an email. It is a mix of 3/16" and 5/32".

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hewebb
Admiral

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USA
761 Posts

Response Posted - 04/09/2012 : 04:25:15

David

I have a loos gage but have not yet used it. What tension do you set your stays at? I have looked for a value and ask around here but have not yet determined where to set them. I think I have my rear stay quite tight and the side stays tight but they will loosen in a stiff wind.
I plan to check the side stays with each other to see if they are all about the same. Seems that when I get to the boat I end up going sailing and tend to forget checking them.

Howard

Edited by - on

pastmember
Master Marine Consultant

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2402 Posts

Response Posted - 04/09/2012 : 06:36:13

If you have not raked the mast back, (about 7" at the top), then your aft lowers may be a bit short. The masthead design can easily have lee helm if the mast is not raked a little. I would probably add a toggle at the bow to allow for rake before I would add toggles to the aft lowers to add length.
You don't need two Loos because the setting you settle on is up to you and either loos can show you whether or not you have the sides balanced. Stand on the coach roof, reach out at shoulder height to attach the loos, that way you are measuring from the same point on all shrouds and you are far enough from a turnbuckle that the tension will register accurately.
As for how tight you set the rig, I sail in a high wind venue and do not like rigging flogging on the lee side so my rig was always tighter than most here on this forum. It is true though that a loose rig is a fast rig. Remember you are probably surrounded by other sailboats at your marina, ask racers what tension they set for in your local and then ask if you can pluck their rigging. After you get a sense for the sound of the tension used in your area then you can tune your rig by sound, then use the loos to fine tune it into balance.

Edited by - on

dmpilc
Master Marine Consultant

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USA
4593 Posts

Response Posted - 04/09/2012 : 09:38:01

You have the tall rig, so your upper shrouds should be attached to the outer holes on the deck chainplates. With the 4 lowers attached but loose, tension the uppers to between 25 and 30 on the loos gauge keeping the mast plumb side-to-side. One side may need to be a tiny bit tighter than the other to stay plumb. If you have an adjustable backstay, tighten the forestay just enough to insert the cotter pins/rings. I like to have at least 2 threads visible "above" the cotter pin hole for safety. The rest of your fore/aft tensioning will be done with the adjustable backstay. If your backstay is not adjustable, tighten the backstay to rake the mast back about the fore/aft diameter of the mast (or as Frank indicates, 7" if you can achieve it). Next hand tighten the 4 lowers being careful not the bow the mast in any direction, then tighten with tools 1/4 to 1/2 turns each, in rotation, until the afts read 10 on the loos and the forwards 15. The main point in tightening the lowers is that you don't want to bow the middle of the mast to one side or the other. I like to keep the afts a bit looser than the forwards so the mast can rake a little more forward while sailing downwind. However, if you do not have the adjustable backstay, it may make more sense to tension all 4 lowers equally to 15 on the loos. You should be able to stand at the mast, grab both forward lowers about shoulder height and, pulling toward you, feel equal tension. Same with the aft lowers. Then go sailing and test the handling. Sailing close-hauled, it should feel about the same on either tack.

Edited by - dmpilc on 04/09/2012 09:50:42

awetmore
Master Marine Consultant

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USA
1144 Posts

Response Posted - 04/09/2012 : 09:57:14

Thanks for the additional help. We do have an adjustable backstay. Our current main is extremely stretched out, so raking the mast backwards would result in the boom becoming a head kicker. I have a new main on order, and when that arrives I'll try raking the mast as you described. Having the mast raked back a bit would fix my issues with the lower shrouds.

Our shrouds are connected to the outer chainplate holes.

There are a few 26' Thunderbirds setup for racing in my tiny marina, I'll check to see what their rigging feels like. We don't have any other Catalinas except for an ignored/neglected C-27. The Thunderbird is more of a racing boat and appears to have a keel stepped mast instead of deck stepped.

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