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Ok...I just said to my wife, "You know, I think I can fix this rigging myself..." We had an after shroud break on the delivery along with a fore stay. The release in the tension caused the mast to shift now it leaks at the deck into the head.
The boat is a gaff rigged ketch and I am calling a rigger...HA Thank you for the info, I am not a moron, but this is beyond my current skill level.
 
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nice topic and great info...

i race in one design keel boats some of the time. rig tune is paramount to sucess. so i thought i would chime in a few fine points for those looking for them (like the comment on how to tune your rig for 20 knots).

sailboats have generally two modes upwind. seeking more power, and seeking less power, with a small happy medium in there. there are of course things we do with strings to help with this, however, mast tune is more significant, that is like a coarse adjustment, the strings we pull the fine adjustments.

i would also side with the disclaimers that have been mentioned, but you may want to consider going too much with an adjustment. that is go too far, far enough that you will know it is too far (performance will suffer). then you will know it is somewhere between those values (of too little/too much).

all of this is for uphill travel...

mast position in the boat (fore and aft) is critical. every boat is different in this regard. talk to other people with your boat and see what they have found out. with the butt, partners and forestay length you can control mast rake. if you have too much weather helm with mast rake right, the mast needs to move forward. not enough, mast needs to move aft. this is assuming your are trimming everything right. highier winds we use less rake, that is we shorten the forestay for the same butt position. other boats move the butt around. both work, but forestay length changes other things as well, and i think is generally easier. i don't know the math on degrees, as we measure the forestay length for the adjustment, but i would suspect we vary the rake by several degrees.

optimizing for light air. forstay sag is good in light air as you are trying for max power. you can try the same on the luff of your main by letting it sag off. how much, well you can try too much and then tighten up from there. too much sag will break/bend your mast. don't send me the bill. i would think somewhere around one to one and half mast diameters would be ok. this is what we use. as the wind builds and the boat is not needing as much power you can bring the mast in line. you do this by adjusting the lower/intermediate shrouds.

for high winds, the opposite is true. you will want no forestay sag (impossible), shorter forestay, less rake (butt aft, wedge partners forward). you will want your mast straight side to side, with more prebend. ideally, you will want the top of the mast to fall off some. fractional rigs do this better.

you can adjust some of this with a backstay adjuster, but really you need to get up there and adjust your forestay length/butt/parnter position to optimize your boat for any particular windspeed. most people in crusing, even racing boats will not play with there upper/intermediates/lowers at all. they have a set it and forget it attitude, especially with discontinous rigs. there is nothing wrong with that, in fact a lot of sense. tune for midrange and use other adjustments to keep the boat on its feet/use the engine if there is not enough wind.

downhill is different of course and mast tune is not as critical. you will want to undo as much rake and prebend as possible with your set up. having the mast tilt forward is best. you cannot do this with spartite, but you can with removable fore and aft wedges.

best of luck...
tom
 

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What a great Sticky.

Just wanted to add a tool that I recently picked up from Lowes. I havent tested it yet but as per the original post stating the importance of a level boat to start with I think this might help and actually picked it up prior to reading this.

It is a Ball level. If you are not on level ground you can figure and mark the level horizontaly then compensate for vertical and even check the degree of angle on the rigging from port to starboard and make certain they are equal .
 

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Hey everyone. I'm new here (as I'm sure you can tell). As we are talking gear, what tools do you think makeup the perfect small toolbox? What tools do you rely on more than others?

I have several tool boxes for sailing, packed full of random things, so i thought it would be good to see what is absolutley essential.
 

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#1 thing for EVERY tool box is a roll of duct tape. There are few things that this stuff can't fix or help fix. Just wish I had invented it!!!
 

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OK, I have done some homework. I have read and then skimmed these posts, learned a couple of new words and will be able to impress my big boat friends. I just bought, however, a sweet little 10' dinghy in an auction. It is not a Minto. It is fiberglas with teak trim. When I unwrapped the wood mast and sail I found a gaff rig. I then noticed a number of brass (bronze) rings, jam cleats and holes scattered throughout. I have found a drawing of a gaff rigged larger dinghy on the internet, but I cannot tell some of the drawn lines are edges or lines (for attaching things). Does anyone know of a source of a rigging diagram for one or more of these boats?

I shall send a photo of the boat when I have cleaned it, oiled it, etc. I would also like to know who built it and its name if any. I heard a rumor during the auction that it was built in England.

Thanks,

Nodiaphoresis
 

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Nice, marking
 

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propellor hat approved

Nice technical rig tuning post.

Just to clarify a few basic engineering principles.

Engineering strain is dimensionless. So multiply by length to calculate actual stretch to achieve a certain preload.

Strain is for the elastic range of the material. Cross sectional area or wire diameter is not a factor.

Preload by strain is the most accurate and repeatable method of tensioning (preloading). We also use it for bolts, pin joints etc.

The whole purpose of preload is to avoid unloading the rigging under any conditions. You want the minimum preload your rig can accept. Any more is just compression loading the mast and lowers the buckling stability of the mast.

Ideally you want to know how much your rig will move under all conditions. This is impractical to do on an actual vessel. So rules of thumb apply with caution.
 

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al brazzi
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Lets try and start this back up. I know its not my thread but can we agree to not spend too much time discussing all aspects of stretch and such. Lets assume there is a Loos type guage available. I have some basic questions and some from the old thread not answered because (my opinion) too much time was spent on digression.

It was questioned early on how to get the desired bend after the rake is set. Its my contention that backstay and either Baby stay of forward shrouds and a bendy mast (not all are) are the tools. Lets talk about the methods and application.

I'm currently sailing a CS 30 Fin keel, spade rudder with a very small partial skeg. Baby stay and inline shrouds, Selden mast. No Backstay adjustment although I would like to have some.
 

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Keel stepped? For and aft lower shrouds? And you say the backstay is not adjustable. But there is a turnbuckle, right?

I would think rake and bend are setup together...
 

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al brazzi
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Keel stepped? For and aft lower shrouds? And you say the backstay is not adjustable. But there is a turnbuckle, right?

I would think rake and bend are setup together...
Keel stepped w/inline shrouds. No apparent adjustment on the step. Don't know that I need adjustment there. It was not clear that bend and rake are set together. I would think rake is fore aft stay adjustable and bend is created with backstay tightening with either a Babystay or a forward lower shroud helping the bend get started.

Backstay is adjustable of course but not underway.
 

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The bend will be induced at the partners. If the masthead is where you want it, rake, then adjusting the mast forward in the partners will induce some bend. I wouldn't use the baby stay as the principal way to induce bend but rather the combination of the mast step, partners, forestay, and backstay. The baby is more to prevent pumping in rough weather...for stability...in my usage.

If the mast step is not adjustable then the partners must be adjusted, and vice versa. My current setting is a bit weird because the partners has the lower third of the mast slightly bent forward. Not much but just enough to bother my eye when riding up in the dinghy. Something got goofed up last time the rigging was replaced as there is an extra toggle in the forestay, too. Other than the annoying lack of aesthetics everything is perfect.
 

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Is the baby stay adjustable? With in line shrouds it's the only way to induce bend unless you've got a very powerful (hydraulic) back stay and/or a bendy rig. If the step is adjustable then you might be able to prebend by using the partners as a 'fulcrum' as you pull the masthead aft to set rake.

The luff curve of your main is going to dictate the amount of prebend you want/need.
 

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al brazzi
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The bend will be induced at the partners. If the masthead is where you want it, rake, then adjusting the mast forward in the partners will induce some bend. I wouldn't use the baby stay as the principal way to induce bend but rather the combination of the mast step, partners, forestay, and backstay. The baby is more to prevent pumping in rough weather...for stability...in my usage.

If the mast step is not adjustable then the partners must be adjusted, and vice versa. My current setting is a bit weird because the partners has the lower third of the mast slightly bent forward. Not much but just enough to bother my eye when riding up in the dinghy. Something got goofed up last time the rigging was replaced as there is an extra toggle in the forestay, too. Other than the annoying lack of aesthetics everything is perfect.
I have some work to do, after running out of adjustment on the backstay, I took a couple of turns on the headstay (furler) now I need to start from the beginning and measure the rake if the headstay needs to go out then the Backstay may be too long.
I need to see what the arrangement is on the partners. I could pull the boot up and see how its assembled but I'm not ready to pull the mast right now and the boot is leaking just a bit and I'm kind of afraid of making it worse.
 

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al brazzi
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Is the baby stay adjustable? With in line shrouds it's the only way to induce bend unless you've got a very powerful (hydraulic) back stay and/or a bendy rig. If the step is adjustable then you might be able to prebend by using the partners as a 'fulcrum' as you pull the masthead aft to set rake.

The luff curve of your main is going to dictate the amount of prebend you want/need.
It has a turnbuckle, but not adjustable underway like C&C does with the short track to pull it out and tension.
My view is a downwind tension on the headstay and a straight mast (with the right rake), then get the bend with a backstay adjuster enough to flatten the Main. A new Mainsail is a need not a want right now and I want to work all the rig geometry out so I can get the cut right.
 

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You can easily check if the partners are reasonable. Good chance they are. Slacken all the stays. If there are fire/aft lower shrouds slacken them too, but count the turns. Observe the mast straightness...just for a starting point. It should be fairly straight. Then apply some backstay tension while easing the forestay until some moderate bend is induced. Is the rake reasonable? If all looks reasonable then the partners and step are in a good place. Tighten everything back up in such a way that the masthead and bend and rake don't change much. If all is not good with just a little backstay tension then something will need to be done at the partners or step. If nothing is done the mast will not have a continuous bend from step to head but two bends. That cannot be good.

In a perfect world the mast is tuned without the fore and aft partners in place. When tuned they are inserted without changing the mast position. That's my method anyway. The step is adjusted to keep the mast reasonably centered in the partners, or perhaps for some other effect...such as my predicament as described above.
 

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al brazzi
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You can easily check if the partners are reasonable. Good chance they are. Slacken all the stays. If there are fire/aft lower shrouds slacken them too, but count the turns. Observe the mast straightness...just for a starting point. It should be fairly straight. Then apply some backstay tension while easing the forestay until some moderate bend is induced. Is the rake reasonable? If all looks reasonable then the partners and step are in a good place. Tighten everything back up in such a way that the masthead and bend and rake don't change much. If all is not good with just a little backstay tension then something will need to be done at the partners or step. If nothing is done the mast will not have a continuous bend from step to head but two bends. That cannot be good.

In a perfect world the mast is tuned without the fore and aft partners in place. When tuned they are inserted without changing the mast position. That's my method anyway. The step is adjusted to keep the mast reasonably centered in the partners, or perhaps for some other effect...such as my predicament as described above.
Do you use an adjustable backstay or just set and forget it. Do you race, I do some clubbing and a Bay race or two but may want to do a lot more if I get my rig right.
 

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My backstay is hydraulic. On this boat the backstay adjustment is mostly for headstay tension. Pumping it on does bend the mast, of course, but that bend is usually mostly removed with the runners to give the main some shape. But whatever it takes to get the job done...that's my principal rule. I race and cruise. Cruising is not lazy for me. Always optimizing performance and comfort.

I have the mast setup so that with the backstay off, baby off, runners off, not sailing, there is about 2 inches of prebend in the 60 feet of mast above the deck. The aluminum section is 8" deep. Then while sailing I adjust things as appropriate. 2" of bend gives a nice full main luff. No bend makes the luff a little too loose. More bend, maybe 8", a full diameter, flattens the main nicely, like a door, more so at the top. The conservative limit is 1.5 diameters, 12", of bend. I have the hydraulic cylinder set so that with no runners on I cannot go much past that amount of bend.

I went up in the bosun chair and measured the static bend at three places. The sailmaker uses those measurements for the sail. It is a truly beautiful thing when done right.

The babystay is really just there to hold on to while on the foredeck :) It doesn't seem to do anything for bending. My spar builder agrees. It is rather an old fashioned thing, however is handy when bashing thru seas. Especially with bare poles or no wind.
 

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al brazzi
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My backstay is hydraulic. On this boat the backstay adjustment is mostly for headstay tension. Pumping it on does bend the mast, of course, but that bend is usually mostly removed with the runners to give the main some shape. But whatever it takes to get the job done...that's my principal rule. I race and cruise. Cruising is not lazy for me. Always optimizing performance and comfort.

I have the mast setup so that with the backstay off, baby off, runners off, not sailing, there is about 2 inches of prebend in the 60 feet of mast above the deck. The aluminum section is 8" deep. Then while sailing I adjust things as appropriate. 2" of bend gives a nice full main luff. No bend makes the luff a little too loose. More bend, maybe 8", a full diameter, flattens the main nicely, like a door, more so at the top. The conservative limit is 1.5 diameters, 12", of bend. I have the hydraulic cylinder set so that with no runners on I cannot go much past that amount of bend.

I went up in the bosun chair and measured the static bend at three places. The sailmaker uses those measurements for the sail. It is a truly beautiful thing when done right.

The babystay is really just there to hold on to while on the foredeck :) It doesn't seem to do anything for bending. My spar builder agrees. It is rather an old fashioned thing, however is handy when bashing thru seas. Especially with bare poles or no wind.
Are your stays inline or spread for some aft support. I suppose the mast just wants to bend that way? so pulling on it just makes it bend. I've also heard the Baby Stay helps keep the mast in one piece with heavy spinnaker loads. Yea or nay on that.
 
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