Back Stay Adjuster

[Don Guillette]

OK, I see the confusion. Sorry about that. I was wondering where "on my Cal 20" came from. I've never owned a Cal 20 and would not know one if I fell on it. "On my Cal 20" was the subject line Dick Westwood used and I just quick replied to his message and it came up. I never thought twice about it.

I am not a rig tuner and I don't know many non professional sailors that are as good as a professional rigger. My bag is not tuning rigs - it's sail trim. Tuning rigging has nothing to do with sail trim controls other than the controls work better when the rig is properly tuned.

Here's the way this forum works. Folks ask questions and I give an opinion. I really don't care if anyone agrees with it or not. It is an opinion, which I back up with facts and people take it or leave it. If different opinions come up in the discussion that is fine as that is what makes this forum go round. With differences of opinion I rarely comment on them unless they are way off the wall, which RichH's wasn't. In fact we are both in agreement. In any event, if there is disagreement I always suggest the reader try both and see what works for them.

 

[tsmwebb]

OK, I see the confusion. Sorry about that.

Probably my bad -- I just pulled four bad parts out of a mold and am feeling grumpy.

I was wondering where "on my Cal 20" came from. I've never owned a Cal 20 and would not know one if I fell on it. "On my Cal 20" was the subject line Dick Westwood used and I just quick replied to his message and it came up. I never thought twice about it.

Kewl. The Cal 20 is a Lapworth design from the 60's. It has a fractional rig of conservative dimensions. They made oodles of them -- I think it is the second most numerous production keel boat in the world. You've probably seen many of them without knowing it.

Tuning rigging has nothing to do with sail trim controls other than the controls work better when the rig is properly tuned.

Huffing too much resin I suppose, but I think I'm missing your point. A decent set of performance sails will be paired with rig tuning guidance from your sail maker -- big firms like North publish rig tuning guides for use with their sails for most popular racing classes. If your rig isn't tuned the way your sailmaker intended no amount of tweaking sail trim controls will make your sails fly as they were deigned to.

... In fact we [RichH and Don] are both in agreement.

Oh. I thought you were saying that a backstay adjuster on a mast head rig was like painting flames on a Corrola and if anything likely to result in excessive rake and RichH was saying that it was a critical tool for (if nothing else) adjusting head-stay sag and not likely to effect rake very significantly...

--Tom.

 

[Don Guillette]

OK, I see the problem. "On my Cal 20" was the subject line of a post from Dick westwood. I've never owned a Cal 20 and would not know one if I fell into it.

That takes care of that. Now I'll deal with 2 issues I have with you. I don't know how you came to the conclusion I "blew off" RichH. I agreed with his post. Here's how I run this forum. Folks ask a question and I give my opinion. Others are free to give their opinion. I rarely question other sailors opinions unless they are completly off the wall. RichH is NEVER off the wall. He always backs up his opinion with facts to support his stand. In all differences of opinion I suggest forum listers try all suggestions and see which one works for them. Recently, I was reviewing a subject and found an article by Buddy Melges. I found another one on the same subject by another asuthor. Both were dealing with the same subject and neither was the same. I tested both systems - Buddy was right.

I know nothing about boat hull construction, sail construction or rig tuning. The better a boat is tuned the better the sail trim controls work. Rig tuning is not my bag - sail trim is. I should have taken Stu Jacksons advise and referred this subject to the archives but since sail trim is a revolving door with new sailors coming in and old sailors going out I don't mind going over and over the same subject time after time.

Your conclusion that "you have the feeling I'm not familiar with mast head tuning" is off the wall. Tuning rigs has nothing to do with the subject we are discussing. Lets assume you really ment SAIL TRIM instead of rig tuning. I will match my sail trim knowledge and experience against 75% of the sailors worldwide and anyone on this list and that includes you.

This subject was boat specific (Catalina) and was regarding the ability to bend its mast, which is not possible. How we got on this tangent is beyond me but this subject is now closed and I'm glad to see it die. Next time it comes up I'll take Stu's advise !!

 

[Dick Westwood]

Seeing is believing: a bent Cal 20 mast!

There's a lot of hot air here about whether or not Cal 20 (or other production boat) masts bend. So: for those of you who think it doesn't occur, I took a picture straight up my Cal 20's mast, with some backstay tension applied. (I took the main off to make it clearer: working hard for you guys!)

In the picture: aft is to the (upper) left. The triangular gizmo you see near the top of the mast is the jumper arrangement. I keep my jumpers fairly tight. If I slacked them off, I'd be able to get more bend than currently. (The big-looking pole thingy going downwards in the picture is the starboard spreader. Some of the other stuff is halyards. Sorry I'm not a better photog!)

You can very clearly see the mast bend, particularly above the headstay attachment where it the mast looks to bend back about 10 degrees at the level of tension I applied. The lower section (below the stay attachment) bows forward, but less dramatically because this lower arc is spread over the 7/8 of the mast below the attachment. (Cal 20 = 7/8 fractional rig.) This is not rake, gents, it's bend.

Further: this is without applying the jib halyard (it's slack in my picture). Cal 20 racers also increase bend by tensioning their jib halyards – much as dinghy racers do. (Allegedly, this brings the bend lower down the mast - apexing at the spreader attachment - because the halyard tension gets transmitted to the mast via increased shroud tension and hence the spreaders pushing forwards. I've not tested this in practice so cannot confirm.). If I'd cranked my halyard, I'd be showing you more bend than in the picture. But it's a control I don't personally use, and Don's question was specific to backstays, so I didn't bother with it here.

I think this should settle it. Yes, a Cal 20 mast bends. It's because it's a fractional rig. Pull the top back; hold a lower part (the jibstay attachment) more or less in the same place – it has to bend (unless your headstay's made of elastic). Some masts may be bendier; some less so. Mine bends, and it helps me to flatten my sails.

If in further doubt: contact the Cal 20 class association, or go to the North Sail page on one-class Cal 20 racing, or talk to the boat's original rigger - Steve Seals. All will tell you about mast bend on this boat, and how to use it to your advantage. Asking those who've studied a class of boat for years (40+ years in this case!) generally works better than making up a general principle and guessing it applies in all cases.

Better yet, come out on my boat to check for yourselves. (Or, in your case, fall into the boat, apparently, Don ) You will observe a backstay adjuster flattening the sails and, as such, working as a useful part of the system alongside the other controls I mentioned. At which point, I shall expect you to buy me a case of beer. After drinking the beer, we'll find something else to argue about. And who knows, perhaps, this time you'll be the one who's right!!

Meanwhile, I accept Don's gracious compliment. Means a lot coming from you, Don.