sail size difference

keiran searle AUS

New Member
i have just got a new 4.7 sail because my old sail seemed to have a belly on the bottom of it and my performance seemed to be deteriating when i was putting my numbers on my new sail i decided to lay my old sail on top just to see the difference it was amazing with my old sail being 2-3 cm smaller than my new sail and looked to have a totally different shape to the old one why is this i thought it was a one design class i now keep my new sail rolled and out of sun the 1st time i saied with my new sail was at the CHS (combined high schools) regatta last week i was the 1st 4.7 over the line every race and ended up getting a big @ss trophy but i was not alone tom won the full rigs ( the one who has issues with chevy) any wasy enough bragging can anyone explain why my sail is so small i will try and find a pic of the belly of the sail.
 
i took to long to make the pictures smaller so it said i could no longer edit the post so here are the pictures the sail was 2-3 cm small than my new one all the way around
 

Attachments

  • tlf02.jpg
    tlf02.jpg
    57.9 KB · Views: 47
  • tlf01.jpg
    tlf01.jpg
    71.9 KB · Views: 59
keiran searle AUS said:
i took to long to make the pictures smaller so it said i could no longer edit the post so here are the pictures the sail was 2-3 cm small than my new one all the way around
It's just my guess that the sail fabric doesn't shrink, being a synthetic, but it can distort. The fabric for the "belly" has to come from somewhere. I have a sail with a belly. When I get a chance (when it's not raining here), I'll lay it out with a newer sail of the same make and see if a similar distortion has happened. Someone out there have a formula for the law of conservation of sail fabric?

Merrily
 
Congradulations on your recent sucess at CHS regatta.I've just come back to Laser sailing and would appreciate details of your clubs racing program.I live at Valla Beach south of Coffs and have previously done Bridge to Breakers a few times in cats Regards Rob
 
well rob only a couple of weeks of sailing left there is a club at coffs i am not sure wat is sailed there. i would put u on to our club website but it is down at the moment feel free to contact me about anything and welcome to laser sailing
 
keiran searle AUS said:
i took to long to make the pictures smaller so it said i could no longer edit the post so here are the pictures the sail was 2-3 cm small than my new one all the way around

It's hard to judge by the pictures, but it almost looks like the second panel up was cut out with the wrong thread orientation or from a different lot of cloth with different stretch properties. (The second picture shows that the panels above and below are more "relaxed" while the middle panel is tight)

Comparing sails without load will usually result in the older sail be slightly smaller, mainly due to the greater number of folds/wrinkles (try the dollar bill test, take two new dollars, wad one up and then open it up and lay it on top of the unfolded one)

A better comparison is when both sails are on the spars, going upwind, the clew and tack should be in approx the same position on the boom and mast for both sails with the same tension applied to both sails on the controls.
 
Merrily said:
It's just my guess that the sail fabric doesn't shrink, being a synthetic, but it can distort. The fabric for the "belly" has to come from somewhere. I have a sail with a belly. When I get a chance (when it's not raining here), I'll lay it out with a newer sail of the same make and see if a similar distortion has happened. Someone out there have a formula for the law of conservation of sail fabric?

Merrily


Interestingly enough (at least to me :) ), synthetics do change dimension. Nylon (spinnakers/gennakers) is really affected by humidity, the higher the humidity, the bigger the sail gets. It's not uncommon to have a wet or damp spinnaker not measure in to class rules and be perfectly legal once it's dry.

Mylar shrinks based on heat, so laminated sails with mylar in it will become smaller, especially when left in high heat areas (such as a car with the windows up on a hot day where the inside temps reach over 100F degrees)

Dacron (the stuff Laser sails are made from) is better in both regards to the above variables but it can suffer from permanent stretch if subjected to too much load. (loose, fluttering leech on the Laser is a good example, as is the fact you have to keep putting more and more cunningham on as the sail gets older)
 
Yeh the funny thing is you bought your own big @ss trophy for chs because there wasnt enough boats to make a division.
 
tom 1 i dident by the trophy it came out of the club money so did gabes trophy they are both perpeutal trophys so they have 2 go bak and some one else will get them next year someone had to buy the full rig trophy dident they and there wasnt 8 fulls last year but big tom still got it also u going up to full rig for chs was not just for
"pratice "was it it was because in the expected conditions gabe would of floged u and if i bought the trophy i would get one like 3923645 times bigger just to show u up
 
yes rumsey! I actually moved up to full rig because i am moving into full sometime this coming year. CHS served as a training regatta aswell as to get some results in the full rigs. As you might have known i also sailed full rig at the youth squad selections! so i dont think that gabe beating me would be the reason. As you know yourself i can hold my own very well against gabe in the light stuff even though im 5kgs heavier than her. Speculating isnt a good thing my friend. (and by the way in the first post from keiren i was supposedly "bragging" i think not!@)- This is the reason for my outrage!
 
sorry my mistake i typed,

i was not alone tom won the full rigs ( the one who has issues with chevy) any wasy enough bragging can anyone explain why my sail is so small i will try and find a pic of the belly of the sail.

wat I meant 2 type was ,

i was not alone tom won the full rigs ( the one who has issues with chevy.) any way enough bragging can anyone explain why my sail is so small i will try and find a pic of the belly of the sail.

therefore implying i was braging in my 1st post. not me saying you where braging hopefully now the problem is solved
 
Wavedancer said:
Are we a bit off track down under? Honestly, you guys should settle your differences privately.
Yeah, what happend to the discussion of, say "sail size difference", like the thread-title says?!?
 
well all settled now

Um the reason for this streching could be moisture on that part of the sail when packed away, that particular part of the sail may have been made from an end of a roll or a thin sail cloth layer. Also un even pulling on the sail
 

Back
Top