Sails!!

[USCGRET1990]

Originally Posted by blt2ski

Me thinks the foot and luff are backwards, the foot is probably 10', and luff 25.5'! This with a 2.5 luff to foot ratio puts you at the bottom end of the IOR rules, as an example, my foot is also 10', but the luff is 32.3'!

I was always explained that a 150 would be an LP of 15' if the J value was 10', it had nothing to d with the actual sq ft of the sail. as one takes teh LP divides by the J value to get the % of sail you have. Hence how I got my numbers in above post.

marty

yea...I switched the luff and foot...so using my measurements what do you thinx the percent is then?
Genoa Demensions:Foot 17.5'
Luff 27'4"
Appx. Leech 30.5'

[Alden68]

Originally Posted by USCGRET1990

How the heck do you figure the area of a sail when it's not a perfect triangle?

You have to break it down into 2 right triangles and then do the math: base X height divded by 2

[blt2ski]

I personally could not figure out the %, as I do nto know your J value, ie mast to headstay measurement. THen I need teh measurement from teh luff to the clew! of which is none of the above. One might be able to plot on graph paper the above foot, luff and leach to make a triangle, then you would have a LP measurement to divide into the J measurement.

OR, you have to pull the sail out of the bag, measure the LP. Then divide that into the know stock J, or measure the J to verify what it is. That is how I would do it.

As far as measuring the acutal area when things are curved..........I have seen locally PHRF trying to take for mains any how, foot measure ment, then halfway tween boom and top of main a width measure, then halfway again a measure, then they can tabulate how much area you really have.

This has come about due to folks with radical roaches increasing there sail area if you will vs the (foot x luff).5 that one normally does for a triangle sq footage.

[blt2ski]

Now looking a jib numbers again, you have the luff and leech numbers backwards. At least that is how my sails are, the luff is larger than the tail side leech, with the foot at the bottom.
A swag, the LP would be about 14 to 15' or so with out trying to scale out as I was mentioning before. With a J of 8' as mentioned, 15/8 = 187.....14/8 = 175.....

[USCGRET1990]

Originally Posted by blt2ski

Now looking a jib numbers again, you have the luff and leech numbers backwards. At least that is how my sails are, the luff is larger than the tail side leech, with the foot at the bottom.
A swag, the LP would be about 14 to 15' or so with out trying to scale out as I was mentioning before. With a J of 8' as mentioned, 15/8 = 187.....14/8 = 175.....

geeeze if I'm going to be this goofy I might as well get drunk
Last Time...
Foot Luff Leech
Main 10' 25'5" 28'
Genoa 17'6" 27'4" 30'6"
Head Stay to mast 8'
Ball Park % of genoa______
Take an educated guess...anywhere near 180%?...or more like 150%.

[Alden68]

using rough math I get around 160....

but that is with the sq footage calc that may or may not be the right math to use

[blt2ski]

LOL,

I think it is close to 180, as in last line or so in my last post. I am swag'ing, ie scientific wild ass guess your LP is about 14-15', divide that by the 8' measure, and you have 175-187 for a final answer. I do not think you are near 150.

That is a big sail, and not uncomomon for early 70's boats. Your main being about 125sq ft or so. mine is listed at 160, but I know of one person that just got a main made at about 190# going with max roach for the same boat.

Another thing you can do, is go to the FX sails site, input your boat make and model, and that will tell you the I, P J E measurements of you boat, you can go to teh make a sail part, and see if there 180 genoa would be close to your known measurements. If off an inch or two, no biggie, if off more than that, you may not have a 180 persay, then play with the programe untill you come up with a sail that has numbers more or less with your numbers. UNLESS of course, that is how you got your numbers.........then all bets are off.

Any way, it has quite raining, I need to go get layed by some pavers, or is that lay some pavers, so I can pay for the haulout of my boat that has happend, and hte new bottom paint, intruments..........

Hopefully this has helped, and not confused.

Then as Brenda would say, have some rum!

[USCGRET1990]

Originally Posted by blt2ski

LOL,

I think it is close to 180, as in last line or so in my last post. I am swag'ing, ie scientific wild ass guess your LP is about 14-15', divide that by the 8' measure, and you have 175-187 for a final answer. I do not think you are near 150.
Sorry, you didn't put % behind those figures, so I didn't catch it.

That is a big sail, and not uncomomon for early 70's boats. Your main being about 125sq ft or so. mine is listed at 160, but I know of one person that just got a main made at about 190# going with max roach for the same boat.

Another thing you can do, is go to the FX sails site, input your boat make and model, and that will tell you the I, P J E measurements of you boat, you can go to teh make a sail part, and see if there 180 genoa would be close to your known measurements. If off an inch or two, no biggie, if off more than that, you may not have a 180 persay, then play with the programe untill you come up with a sail that has numbers more or less with your numbers. UNLESS of course, that is how you got your numbers.........then all bets are off.


Hopefully this has helped, and not confused.
A big help, thanks a bunch
Then as Brenda would say, have some rum!

If I do, it will "Cap'n Morgan" for sure

[bestfriend]

Just fly the thing and if it drags your bow under water its too damn big!