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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

Backstay, Adjustable, Standard Rig vs. Stand. Rig

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Allmanjoy
1st Mate

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USA
44 Posts

Initially Posted - 04/13/2020 : 10:02:20

So couldn't find anything in the search on this subject, so trying to understand a couple of things on replacing my Backstay.

I'm new to sailing and still learning the basics. I need to replace the backstay, and figured since I am new to sailing that I'd just replace it with a standard set up. The adjustable backstay seems very interesting, but the forestay attaches to the top of the mast so is the adjustable backstay that advantageous? (Being that the top of the mast can't bend aft for a tighter camber.)

Hope that makes sense, still learning the sail speak.

Jay C 1985 C25 SR/SK

Steve Milby
Past Commodore

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USA
5853 Posts

Response Posted - 04/13/2020 : 10:57:35

James, you're right that the top of the mast can't be pulled back any farther. (Well, you can bend the mast a little, if you adjust the stays to permit it, but not enough to really matter.) But that illustrates the fact that there's a widespread, almost universal, misunderstanding of what a backstay adjuster does for a boat like a C25 with a masthead rig. A backstay adjuster doesn't tighten the forestay so that you can point higher to windward. On a masthead rig, it's purpose is to loosen the forestay, which powers up the jib, so that you can sail faster downwind and in light air.

That being the case, I really liked the backstay adjuster on my Catalina 25 TR/FK. I also have one on my Cal 25 that I race. Every time I round the windward mark, and whenever the wind goes light, I ease the backstay adjuster. Often, I'll also ease the jib halyard. The goal is to create forestay sag, which deepens the draft of the jib and powers it up. Whether you race or cruise, a backstay adjuster is a nice control to have, because racers and cruisers alike like to go a little faster downwind and in light air.

But, a backstay adjuster certainly isn't necessary. Most sailors enjoy their boats without one. If you're the kind of sailor who really enjoys tweaking the sails, then now would be a good time to add it to your boat. If not, then don't bother.

Steve Milby J/24 "Captiva Wind"
previously C&C 35, Cal 25, C25 TR/FK, C22
Past Commodore

Allmanjoy
1st Mate

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USA
44 Posts

Response Posted - 04/13/2020 : 11:33:59

That makes perfect sense. I appreciate the quick response. Thank You!

Jay C 1985 C25 SR/SK

Steve Milby
Past Commodore

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USA
5853 Posts

Response Posted - 04/14/2020 : 05:00:26

You're welcome.

It would probably be worthwhile to explain why the misunderstanding of backstay adjusters is so widespread. On fractional rig boats, a backstay adjuster does in fact help a boat point to windward in strong winds. The reason is because the forestay doesn't go to the top of the mast, as it does on a masthead rig, and the crossection of a fractional rig's mast is more spindly than the mast on a masthead rig. Consequently, when the backstay adjuster is tensioned, the top of the mast bends aft. That pulls some of the fabric of the mainsail forward, moving the mainsail's draft forward and depowering it.

Because a backstay adjuster works that way on a fractional rig, people assume that it works the same way on a masthead rig, but, as you observed, the differences in the rigs cause different results. Backstay adjusters are useful on both masthead and fractional rigs, but they work in very different ways and are useful for different reasons.

Steve Milby J/24 "Captiva Wind"
previously C&C 35, Cal 25, C25 TR/FK, C22
Past Commodore

Allmanjoy
1st Mate

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USA
44 Posts

Response Posted - 04/14/2020 : 16:08:26

I gained the fractional mast knowledge from YouTube but the video failed to speak about masthead rigs, so thanks for clearing that up.

Jay C 1985 C25 SR/SK

dmpilc
Master Marine Consultant

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USA
4593 Posts

Response Posted - 04/14/2020 : 19:10:33

Thanks Steve, that was a great explanation. glad I looked at this thread. Thanks also James, for asking the question.

DavidP
1975 C-22 SK #5459 "Shadowfax" Fleet 52
PO of 1984 C-25 SK/TR #4142 "Recess"
Percy Priest Yacht Club, Hamilton Creek Marina, Nashville, TN

Stinkpotter
Master Marine Consultant

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Djibouti
9017 Posts

Response Posted - 04/15/2020 : 08:37:51

I didn't have a backstay adjuster on my C-25, but I've seen how the some bend can be induced on a mast-head rig like the C-25's, given its forward and aft lower shrouds. Tuned so that, with the backstay adjuster relaxed, the aft lower shrouds are a little looser than the forward lowers, when the adjuster is tightened, the top of the mast moves back, pulling against the forward lower shrouds as well as the forestay. This allows the forward lowers bend the mast (somewhat). The aft lowers are initially looser so that they can allow the mid-section of the mast to move forward as it bends. It's nothing like a fractional rig with a tapered (or "spindly") mast, but it can be something... This is an example of why serious racers like "loose rigs"--so they can pull on things and make changes. (I was never one of them.)

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

dmpilc
Master Marine Consultant

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USA
4593 Posts

Response Posted - 04/15/2020 : 08:52:47

On our C-22, when racing, We leave as much as 12-15 inches side-to-side play in the forestay and juat barely hand-tighten the aft lowers. Use the backstay adjuster to tighten the forestay going upwind, forward lowers have from 10-20 on the Loos gauge, depending on expected wind conditions (10 light, 20 heavy) and keep the uppers at about 20-25, respectively. This allows the mast to rake forward downwind putting more "bag" in the genoa going downwind.
I remember the C-25 rig being a lot tighter

DavidP
1975 C-22 SK #5459 "Shadowfax" Fleet 52
PO of 1984 C-25 SK/TR #4142 "Recess"
Percy Priest Yacht Club, Hamilton Creek Marina, Nashville, TN

Edited by - dmpilc on 04/15/2020 08:55:59

Derek Crawford
Master Marine Consultant

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USA
3312 Posts

Response Posted - 04/15/2020 : 10:02:37

At the C22 Nationals on Canyon Lake (way back when) I noticed the very loose rigs on most of the boats. Being somewhat of a curious fellow, I experimented on "TSU" and found that we were much faster, especially downwind. I finally settled on Loos Guage readings of 20, 30, 25 from aft lowers forward. When we went to weather the leeward shrouds waved in the breeze - scared newbies on the boat witless. The forestay, with the backstay off, had a good 10" of play, but with the backstay fully on it was rod tight.

Derek Crawford
Chief Measurer C25-250 2008
Previous owner of "This Side UP"
1981 C-25 TR/FK #2262 Used to have an '89 C22 #9483, "Downsized"
San Antonio, Texas

Lee Panza
Captain

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USA
465 Posts

Response Posted - 04/15/2020 : 22:23:48

When I bought my Cat25 the mainsail was hopelessly stretched out. I used the fwd lowers to bow the middle of the mast forward by maybe 5 or 6 inches, and that helped. With the mast that far out of column it may be possible to slightly exaggerate the mast bow by tightening the backstay. The tension compresses the mast, and with that much bow it probably causes it to bend even more. The difference might have been evident in a slight loosening of the fwd lowers, but with the system that far out of normal there wasn't much point in putting a Loos Gage on the shrouds. I'm not recommending this, but it's something that could be done with the backstay adjuster.

The trouble with a destination - any destination, really - is that it interrupts The Journey.

Lee Panza
SR/SK #2134
San Francisco Bay
(Brisbane, CA)

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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.