Mast bend and sail recut (why isn't it as big a benefit to all boat classes?)

[Sneaky Duck]

Ok, so I have asked this question of a couple sail makers and I'm confused so perhaps if I start a thread about it with a few people chiming in.... SOMEONE can put it in terms I understand.

I race/own a Thistle, and a Star. VERY different boats I know one of the biggest differences I think is the $ invested in the competitive campaigns. From what I've been told, top level Star teams buy new masts every few years (not just from breaking them but also because they fatigue and loose some stiffness perhaps over time). They also have their sails cut to match the bend numbers of their specific mast. Thistles on the other hand tend to race with the same mast for decades, and typically sail with the sails straight out of the box.

I KNOW the thistle rig is very different. It's deck stepped, shorter, much stiffer, and has very little adjustability (especially while sailing.). If I understood my buddy when I asked him why none of us recut our mains, he used the adjustability and flexibility as the reason. He said we wouldn't get as much benefit. I'm curious though why that is? IF nothing else, I'd assume that I can "make" my star rig fit the sail with the shrouds/rake/back stays while my thistle is kind of stuck with the shape of the main as is. Right?

Finally, on a boat like a thistle, is there performance gain to be made by swapping the mast for a new one? Would a 2022 mast be faster then my 2004 one?

I guess I just want to know... why would things 1 class does to go faster not translate to another? Should we look at buying a mast and recutting sails for the J/22?

(It's a winter storm out... these are the things I think about.)

 

[CaptainAhab]

You are thinking about it backwards. You need to adjust the Thistle rig so that it works well with it's one design sail.

 

[BoksNoRox]

Your dacron mainsail will change shape after a good deal of use. If your rig is tunable for mast bend you can make the mast fit the slightly different sail shape. I have not sailed a thistle for 50 years so I cannot remember what changes can be made. You can recut the luff to match the mast bend, or optimize the shape for different prevailing conditions. With one design sails you will either end up losing a little area (very) if you take luff curve out, or end up with too large a girth if you add luff curve. these are incremental amounts, but one design classes can be very picky about sail measurements. The big question is it worth the effort. You can just purchase a new sail every two to three years as your class allows. Your sailmaker should be keeping up with prevailing fast sail designs in the class.

 

[Steam Flyer]

You're talking to the wrong sailmaker. It shouldn't be too difficult to find one who will be glad to take your money to recut your Thistle main.

Cost/benefit? You're in the wrong sport buddy.

 

[Marty Gingras]

Yeah, it's about the rules.

Here is an anecdote that may help: We asked a sailmaker what he'd do differently with a main if we installed checkstays on an Olson 25, which would not be class legal but would sometimes be beneficial racing handicap. He said to keep the main legal he'd add some roach because the checkstays could be used to keep the mast straighter than w/o checkstays. W/o checkstays, he'd have to use the allowed sail cloth in the luff to account for the additional mast bend.

 

[DRDNA]

Most sails I used in were cut to fit my mast bend characteristics- even in 1969. The sailmakers often ask which spar maker you use, and in Finns, we sent specific mast bend numbers to sailmakers. I haven’t had any sails re-cut, so I can’t address that issue

 

[Kenny Dumas]

Because whoever wrote the Star class rules was a sailmaker?

 

[Doug Halsey]

Because whoever wrote the Star class rules was a sailmaker?

He must have been a boatbuilder too, since "designing" Star hulls has been a recognized thing

 

[EYESAILOR]

Finally, on a boat like a thistle, is there performance gain to be made by swapping the mast for a new one? Would a 2022 mast be faster then my 2004 one?


(It's a winter storm out... these are the things I think about.)

On a boat like a Thistle, the biggest performance gain to be made, is swapping out the Thistle.

Life is too short.

Happy Xmas

Eye.

 

[slug zitski]

Ok, so I have asked this question of a couple sail makers and I'm confused so perhaps if I start a thread about it with a few people chiming in.... SOMEONE can put it in terms I understand.

I race/own a Thistle, and a Star. VERY different boats I know one of the biggest differences I think is the $ invested in the competitive campaigns. From what I've been told, top level Star teams buy new masts every few years (not just from breaking them but also because they fatigue and loose some stiffness perhaps over time). They also have their sails cut to match the bend numbers of their specific mast. Thistles on the other hand tend to race with the same mast for decades, and typically sail with the sails straight out of the box.

I KNOW the thistle rig is very different. It's deck stepped, shorter, much stiffer, and has very little adjustability (especially while sailing.). If I understood my buddy when I asked him why none of us recut our mains, he used the adjustability and flexibility as the reason. He said we wouldn't get as much benefit. I'm curious though why that is? IF nothing else, I'd assume that I can "make" my star rig fit the sail with the shrouds/rake/back stays while my thistle is kind of stuck with the shape of the main as is. Right?

Finally, on a boat like a thistle, is there performance gain to be made by swapping the mast for a new one? Would a 2022 mast be faster then my 2004 one?

I guess I just want to know... why would things 1 class does to go faster not translate to another? Should we look at buying a mast and recutting sails for the J/22?

(It's a winter storm out... these are the things I think about.)

Don’t know Thistles…they have been around a long time so there must be several masts and class tuning guides
obviously the mast must match the sail . Your sailmaker should know your mast , it’s stiffness and how to set up the mast partners, mast foot and rigging…pre bend

https://cfd.northsails.com/sailing/wp-content/uploads/2017/05/08134957/north-snipe-tuningguide.pdf

 

[Marty Gingras]

I guess I just want to know... why would things 1 class does to go faster not translate to another?

It sorta kinda reads like you don't yet know what's making and what's limiting performance. Here is a link to the best account I've run across of a sailmaker working with one-design racers to optimize for their rig, sailing style, and venue. It may string together some stuff for you:

Ullman Sails 2020 Mercury Nationals Design Debrief | Ullman Sails Newport Beach

newportbeach.ullmansails.com

 

[Steam Flyer]

Don’t know Thistles…

Yep. Thistles don't have partners or most of that stuff. The first step is recognizing bullshit.

The next step is to evaluate the "boots on the ground" situation with your boat. Is the basic rig geometry... the location of the mast step and chainplates, the range of shroud tension, the mast rake, the range of halyard tension and it's adjustability; things like this... acceptable for the boat to be competitive? Take look at the boats sailed by guys who are successful in the class, and talk to them about anything you notice on their boats that is different from yours. Many times, old one-design boats have been diddled with by well-meaning (or eccentric, or cheapskate) prior owners.

The next step after that is to get an actual tuning guide from a successful (ie winning) sailmaker.

Thistle Tuning Guides - Thistle Class Association

Mast tune has a great deal to do with your performance. Here are tuning guides for commonly-held Thistle sails. North Sails (general guide) Fisher Cut Tuning Guide Proctor Cut Tuning Guide Northwest Cut Tuning Guide Quantum Sails Dieball Sails (no longer being produced)

www.thistleclass.com

Thistle Tuning Guide | North Sails

This tuning guide is for the DSD design, VS design and the Proctor design Thistle sails. These designs are the result of hours of boat on boat sail testing

www.northsails.com

(link to PDF file)

https://www.quantumsails.com/getattachment/Sails/One-Design/Inshore/Thistle/Thistle_QuickTuneGuide-June2020.pdf.aspx

When you set up your boat to the tuning guide, it's best to use directions/dimensions specific to the sails YOU have, ie don't use Quantum's guide if you have Schurr sails! However if you're starting from a boat that is not set up properly to begin with, ANY sailmakers tuning guide will be an improvement, because you'll learn what the basics and the goals are, and how to achieve them with your specific boat. This is a lot better than trying to sail a Thistle as though it were a Lightning or a Flying Scot.

I've only sailed Thistles a little, and never owned one. Frankly I don't like them much, I much preferred the Lightning and then later, the Buccaneer. But you have one, you seem to like it, so work -with- it, not against it!

 

[LionessRacing]

On a more general note: your sails & spar are an investment that degrade with time. Whether your budget & class rules allow you to have frequent replacement or venue optimized sets is a separate question. Assuming you are limited to one spar & set of sails at a time, the question then becomes what conditions do you want to cover and do you want to optimize for an "end" of a range, or try to go for a more general. Your allowed spar & rig tuning should influence that, as well; as your crew size/weight and skill.

On "Lioness" we have basic controls: Sheet, traveler, outhaul, Cunningham, vang, halyard, reefing lines and a turnbuckle backstay adjuster in order of adjustment frequency. We set the forestay and shrouds and pin them for years.

 

[EYESAILOR]

On a more general note: your sails & spar are an investment that degrade with time. Whether your budget & class rules allow you to have frequent replacement or venue optimized sets is a separate question. Assuming you are limited to one spar & set of sails at a time, the question then becomes what conditions do you want to cover and do you want to optimize for an "end" of a range, or try to go for a more general. Your allowed spar & rig tuning should influence that, as well; as your crew size/weight and skill.

On "Lioness" we have basic controls: Sheet, traveler, outhaul, Cunningham, vang, halyard, reefing lines and a turnbuckle backstay adjuster in order of adjustment frequency. We set the forestay and shrouds and pin them for years.

The tuning lessons from a Bermuda 40 do not translate well to a Thistle.

The tuning lessons from a Thistle do not translate well to anything.

Merry Xmas

E

 

[LionessRacing]

The tuning lessons from a Bermuda 40 do not translate well to a Thistle.

The tuning lessons from a Thistle do not translate well to anything.

Merry Xmas

E

Not in anyway trying to suggest my tuning detail is relevant to anything else. The principle of knowing your boat/class boundary conditions, and working within them certainly is. We don't step the mast for every regatta, and would not think of swapping masts between them. We race with what we have and try to adjust that which is feasible to do so. I theoretically can adjust backstay, practically we don't.