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Catalina 25 Specific Forum

Successful rig tuning - but lots of rake!

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odonnellryanc
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Initially Posted - 05/06/2018 : 14:13:17

Finally got to shake the boat down after shortening the forestay and rigging a new backstay.

I had to shorten the forestay significantly. However even after shortening it after having decent (10-15%) tension on the backstay the rig is very very raked. Moreso than other boats in the marina for certain.

I have the uppers close to 30% forward lowers around 20-25 and the back lowers maybe 15.. rig sails extremely well like this. Almost perfectly balanced actually. Can be put in a close-haul and left like that for a few seconds by itself if the sails are not oberpowered... A gentle lashing of the tiller will literally allow the boat to sail itself for up to an hour. If the boat becomes overpowered it will round up as expected.

Everyone so far as agreed the boat sails much better than last year. More "solid."

However the extreme rake does make me think. Is it possible to have the mast too raked where it would cause structural issues? I can take a few pics but if you dropped a line I'd guess the damn thing is raked past 12"..!

Steve Milby
Past Commodore

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Response Posted - 05/06/2018 : 15:46:54

A 12" rake is way excessive. Look at the photo from the Catalina brochure and you can see that the mast is close to plumb. In actuality, it's probably raked somewhere between 2-4".

When casually sailing back and forth in light to moderate winds, you probably won't notice the excessive weather helm that it causes. When you sail closehauled with full sails properly trimmed in strong winds for long periods, you'll realize that you've become arm-weary, and you'll have to change your steering arm to rest your muscles. With a 12" rake, the center of effort of the sailplan will be too far aft of the keel's center of lateral resistance, and that imbalance will strongly tend to push the stern to leeward and force the bow to windward, and you'll have to pull hard on the tiller to keep the boat from rounding up into the wind. In essence, with a 12" rake, there's too much sail area aft of the CLR pushing the bow to windward.

You can adjust sail trim to balance the tiller pressure. You would do that by easing the mainsheet. That would reduce the power of the mainsail, so it won't tend to push the bow to windward. But, when you do that, you're losing some of the power of the mainsail. The correct way to balance the CE with the CLR is by tuning the rig correctly, not by depowering one of the sails.

If you never race and never sail in strong winds, sailing with too much rake might not be a bother, but if you get caught in heavy weather, you'll need the boat to balance and sail as well as possible.

I doubt that excessive rake will cause structural damage, but it will make the boat unmanageable in heavy weather.

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

Edited by - Steve Milby on 05/06/2018 15:52:00

odonnellryanc
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Response Posted - 05/06/2018 : 16:23:26

I'll have to sail it some more in heavy weather and give an update, but we were in moderate weather and the boat was balanced very well. The wind picked up too much for the 150 genoa and we did round up, but reducing it to about a 120 gave back helm. I'm not sure what the windspeed was but we hit over 6 knots in a beam and the boat was extremely easy to manage on all points of sail: but again maybe it was just very light wind... Though if I had to guess it may have been getting close to 10 knots?

I'm very surprised about this as well. I've done the research on mast rake and honestly expected awful weather helm. It was nothing like the boat was previously. Even when the boat would round up there was not a struggle, it was just the tiller coming out of the water!

I was at first worried about the rake and was planning on shortening the forestay once again. Now I'm not so sure I will.

Stinkpotter
Master Marine Consultant

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Djibouti
9076 Posts

Response Posted - 05/06/2018 : 18:05:40

Other variables are sail trim and sail condition. If you tend to keep that 150 tightly sheeted and adjust the main according to the wind, that will help to negate some of the effect Steve describes. I sailed with a 130 and about 5" of rake on a standard rig, with very comfortable weather helm and no rounding up under any conditions up to the high 20s. (By 30 and above, my sails were down and I was heading for shelter.

)

Sail condition: If your genoa is pretty full regardless of how you sheet it, that will move the CE forward, to be offset by mast rake as you know. In stronger wind, the sheet cars can be aft somewhat to flatten the lower part of the sail, and forward in light air, but an older sail can be too full (too "powerful") regardless.

But in the final analysis, if you're satisfied with the handling and not focused on beating your handicap, you're good. It might be that if you buy a new sail or two (especially a genny), you'll want to re-adjust the mast. The good news is you know what you're dealing with.

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

Edited by - Stinkpotter on 05/06/2018 18:18:33

odonnellryanc
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Response Posted - 05/07/2018 : 04:56:08

Thanks for the advice, Steve + Dave. It's awesome to have these forums to pick the brains of much more experienced sailors, especially those who are familiar with our boats.

One big part of this is I do not have any way to get accurate wind speed! Maybe a cheap handheld is the next purchase ... we'll see.

Other part is I really should measure the rake to get an accurate idea. The mast looks crazy - but part of that is also that I have the forward lowers under about 10% more tension than the aft. This causes the mast to bend somewhat in the middle. I read here (I believe) and on some other resources that owners of C25s liked this because it helped to flatten the main.

Possible this is offsetting the impact of the rake?

Doing the job myself and always doubtful of these things I was expecting a worse sail, but I was surprised with a boat that seemed to handle better than last year (though quite a few months, we took the boat out end of October, so who really knows).

Three people who weren't me did say they liked how the boat handled, but maybe they were being nice!

At least my Sta-Lok fittings held...for now. :)

Steve Milby
Past Commodore

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5896 Posts

Response Posted - 05/07/2018 : 05:36:13

We had lengthy discussions of rig tuning in the following linked threads. They'll help you get the rig set up correctly.
http://catalina-capri-25s.org/forum/topic.asp?TOPIC_ID=30750&SearchTerms=tuning

http://catalina-capri-25s.org/forum/topic.asp?TOPIC_ID=30801&SearchTerms=tuning

The C25 has a masthead rig. Bending the mast is of very little significance to any masthead rig. The mast cross-section is thick and not easy to bend, and the backstay and forestay are attached at the masthead, which makes it difficult to create a bend. Moreover, mast bending with a masthead rig is generally only useful in conjunction with a backstay adjuster. I won my first national championship against 29 C25s with no bend whatsoever in the mast. Some of the competitors did bend their masts. It's of very little significance.

Bending the mast depowers the mainsail, which is only helpful in strong wind. A depowered sail in light or moderate winds reduces the power of the sail when you need it the most. That's why it's only beneficial with a backstay adjuster - because you can bend the mast slightly in strong winds to depower the sail, and straighten the mast to power it up in light winds.

By comparison, a fractional rig has a much more spindly, flexible cross-section, and the forestay is attached a few feet below the masthead. The backstay is attached to the masthead, and, increasing tension to the backstay bends the top few feet of the mast aft.

For now, what's important is to get the mast erect, so it doesn't lean to one side, get it straight with no bend, get the slack out of the stays, and get a 2-4" rake in the mast. If you achieve that, your boat will generally sail well in all conditions.

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

Edited by - Steve Milby on 05/07/2018 05:47:31

odonnellryanc
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108 Posts

Response Posted - 05/07/2018 : 06:10:59

Thank you for the threads, will read them over!

> For now, what's important is to get the mast erect, so it doesn't lean to one side, get it straight with no bend, get the slack out of the stays, and get a 2-4" rake in the mast. If you achieve that, your boat will generally sail well in all conditions.

Well, I've accomplished all these except the too much rake!

The issue is I can obviously lighten up on the backstay to remove all/most of the rake, but if I ease off enough there will be very little if any tension on the stays. I suppose I can give that a shot.

I didn't lock my backstay turnbuckle in: I actually added more tension to the backstay mid-sail because I wanted more weatherhelm! Which did work as intended.

The original goal for this boat was to add a split backstay with an adjuster. I had a bunch of other things to do so I never added in the new chainplate, but I can do so if I want and I may eventually. I have most of the hardware for it anyway.

Edit: it is good to know that I'll probably not damage the mast with this rake. That was my main concern.

Shortening the forestay is not out of the question: it is a job since I have a furler but what isn't?

However, I do enjoy taking the boat out in high winds: it's fun to have to put in a reef, or even two! I'll have to ensure I am extra careful with a rig that has possibly way too much rake.

Edited by - odonnellryanc on 05/07/2018 06:19:20

Derek Crawford
Master Marine Consultant

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Response Posted - 05/07/2018 : 08:12:03

I'm confused here (my often normal condition). If you cut a bunch off the forestay how do you get the mast to rake BACKWARDS?

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

odonnellryanc
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108 Posts

Response Posted - 05/07/2018 : 09:14:14

Derek, I knew the forestay was too long from last season, but it turns out it was much, much too long. My estimate was about a 3-4" reduction.

Previously the backstay turnbuckle was bottomed out and there was still 0% tension on the stay....

In hindsight it may have been best to forget matching anything up to the forestay and instead to try and match up to factory specs.

Stinkpotter
Master Marine Consultant

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Djibouti
9076 Posts

Response Posted - 05/07/2018 : 09:23:28

quote:
Originally posted by Derek Crawford

I'm confused here (my often normal condition). If you cut a bunch off the forestay how do you get the mast to rake BACKWARDS?

As I read it, he shortened the forestay to reduce the rake (further than the turnbuckle could), but still thinks it's excessive. As he said, it would be helpful to get an actual measurement--the distance of the mainsheet (hanging with some weight on it) from the mast at about boom height. I have to wonder how he got 12" with his rigging in the first place unless he had a non-standard toggle on the forestay and had a shortened backstay to get some tension on it. I don't think my turnbuckles (with fixed backstay) could have adjusted that far.

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

odonnellryanc
Navigator

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108 Posts

Response Posted - 05/07/2018 : 09:42:13

Dave,

Achieved the excessive rake mainly due to having TWO turnbuckles on the backstay: I originally planned to install a split backstay + a way to adjust it. It's setup for this still, just need to add the chainplate and the other cable.

Basically, the rig is a cable from the top of the mast to a turnbuckle + toggle that connects to a triangle tang to allow the split. Then another turnbuckle at the chainplate.

The upper turnbuckle is cranked down pretty much all the way, just a few threads exposed. I pinned + taped this. The bottom turnbuckle in the beginning of my sail was maybe 1/4 inserted on each side. Now it is about 3/4. It was raked significantly at the beginning of the sail, so the extra 2/4 on the turnbuckle did not cause the entire 12" of rake.

I originally planned for the more-expensive option of having 2 turnbuckles just for this situation: in case my math was slightly off or the rig slightly different than spec.

Also important to note that yes, everything is locked down as far as it'll go on the harken furler, so I cannot reduce the forestay length at all that way. Only option is to remove my Sta-Lok fitting and cut the cable.

Edited by - odonnellryanc on 05/07/2018 09:43:29

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