I'm trying to figure out what the size the factory furling headsail is on my 2007 Hunter 38.
It's not in the manual (that I can find).
It's not in the manual (that I can find).
What size headsail do I have?
- Thread starter flightlead404
- Start date
Do an internet search on "Hunter 38 specs" to find the stock sail. Likely 282 sqft. Measure it to be sure.
Last edited:
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,214
You can "look at the specifications" but that does not guarantee your sail dimensions.
The answer is to measure it.
Or you can unfurl it and see how far it comes back along the side and reasonably estimate. Take it to a sail loft, they can let you know what you have. A 100% sail will fill the triangle from the mast to the bow and up the forestay to where it affixes to the mast.
The folks at Precision Sails post this blog describing the process.
www.precisionsailloft.com
The answer is to measure it.
Or you can unfurl it and see how far it comes back along the side and reasonably estimate. Take it to a sail loft, they can let you know what you have. A 100% sail will fill the triangle from the mast to the bow and up the forestay to where it affixes to the mast.
The folks at Precision Sails post this blog describing the process.
How to Measure for a New Headsail (Jib or Genoa) - Precision Sails
Step-by-step instructions and diagrams for how to measure for a new head sail, Jib or Genoa. Walks you through the measuring process. If you can read a tape measure you can measure your boat for a new Jib or Genoa!
www.precisionsailloft.com
The very easiest way to determine sail size is to compare the headsail's Luff Perpendicular (LP) with the boat's (J)
LP is a perpendicular line from the sail'l luff through the clew of the sail. In geometric terms this line represents the height of a triangle and the sail's luff represents the its base
The J is the distance from the stemhead to the mast base... it is the foredeck length. It also represents one side of the right triangle created by the mast, deck and forestay.
Anyway, a comparison of the areas of these two triangles will give you a percentage number that represents the sail's size.
Sail area 110sq ft divided by foretriangle area of 100 sf = 110%
But WAIT.... did you forget your jr high school geometry?
..... the shortcut is to simply compare the LP with the J.
The J is often stated with other common dimensions in the sales brochure or sailboatdata.com information sheet.
If the J is 10 and the LP is 11 then the size is 110.
Nerd alert. The amount of overlap depends on the shape of the sail. (high clew, low clew etc) So it is inevitable that a 100 % headsail will, in fact, have a clew that will overlap the mast.
Nerd alert 2..... the LP is NOT the same as a sail's FOOT.... don't blow it with the old salts by confusing the two.
LP is a perpendicular line from the sail'l luff through the clew of the sail. In geometric terms this line represents the height of a triangle and the sail's luff represents the its base
The J is the distance from the stemhead to the mast base... it is the foredeck length. It also represents one side of the right triangle created by the mast, deck and forestay.
Anyway, a comparison of the areas of these two triangles will give you a percentage number that represents the sail's size.
Sail area 110sq ft divided by foretriangle area of 100 sf = 110%
But WAIT.... did you forget your jr high school geometry?
..... the shortcut is to simply compare the LP with the J.The J is often stated with other common dimensions in the sales brochure or sailboatdata.com information sheet.
If the J is 10 and the LP is 11 then the size is 110.
Nerd alert. The amount of overlap depends on the shape of the sail. (high clew, low clew etc) So it is inevitable that a 100 % headsail will, in fact, have a clew that will overlap the mast.
Nerd alert 2..... the LP is NOT the same as a sail's FOOT.... don't blow it with the old salts by confusing the two.
Sorry I was unclear in my initial question.
I'm not asking for specific measurements. I've gone ahead and done all the rig measurements.
I meant, its it 110%, 115% or something else.
I cannot find THIS information in the manual
Thanks
PS when I see "nerd alert" that's usually bit I skip straight to
I'm not asking for specific measurements. I've gone ahead and done all the rig measurements.
I meant, its it 110%, 115% or something else.
I cannot find THIS information in the manual
Thanks
PS when I see "nerd alert" that's usually bit I skip straight to
Measure the sail, too. Since you know the IJPE measurements, then compare the sail measurements, like this:
It is the ONLY way to answer your question.
Measurements for this purpose and for the purpose of ordering new sails are sail only, right? That is EXCLUDING the 1.5" loops at the head and tack used to attach to the furler?
I replaced my factory headsail last season with a sail of the same dimensions. The sailmaker labeled LP as 110%.
Excellent thanks
How do you like those sails? I'm considering the same weight and tri-radial design from Precision Sails for SE USA coastal crusing.
I really worked on my sail trim over the winter and came to the conclusion that my sails are seriously deformed. Yes, really well optimized proper sail trim is a difficult thing to get right, but I'm pretty sure a lot of my lack of success is due to stretch sails.
Also, I think some of my main sail furling issues are to to that problem.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,214
Precision Sails are nice. They will serve your purpose. They are reported to follow up and costs are reasonable. You do the measure and they produce a sail to your instructions.
I chose to use North Sail. They have a Seattle Loft. I met with the manager. Discussed the various cloths, my sailing plans, even what I thought I wanted to get out of the sails.
He came down to the boat and measured the boat. I started with a Mainsail as that was my major problem. I liked what I received. The sail exceeded my expectations. Jack brought the sails to the boat. We raised the mainsail and discussed the features plus trim methods. He checked the cut and assured that the sail met the desired shape.
I went back to Jack to produce a new Genoa, and Asymmetrical. The decision worked out for me. After a year of having the sails, I went back to the loft. They made some minor changes and stored the sails for the winter. All part of the loft service.
Having a local loft can be a bonus.
I chose to use North Sail. They have a Seattle Loft. I met with the manager. Discussed the various cloths, my sailing plans, even what I thought I wanted to get out of the sails.
He came down to the boat and measured the boat. I started with a Mainsail as that was my major problem. I liked what I received. The sail exceeded my expectations. Jack brought the sails to the boat. We raised the mainsail and discussed the features plus trim methods. He checked the cut and assured that the sail met the desired shape.
I went back to Jack to produce a new Genoa, and Asymmetrical. The decision worked out for me. After a year of having the sails, I went back to the loft. They made some minor changes and stored the sails for the winter. All part of the loft service.
Having a local loft can be a bonus.
It was a completely different boat after replacing the 16 year old original sails. The old ones were blown out and baggy. I couldn't get them flat enough as the wind piped up. The luff on the main wouldn't tension and so it fluttered incessantly. The flutter caused pumping that shook the arch. The genoa was poorly shaped as well. As a result, the trim was never quite right. Pointing ability suffered and I thought the boat was tender being quick to heel.
I upgraded to tri-radial to hopefully keep the shape better as the sails age. I also added vertical battens on the main to resolve the flutter and get a little positive roach. I could not be happier. I can actually notice the boat respond to subtly changes in trim and she is much stiffer like the reviews said she was as "boat of the year". You won't regret the investment. I didn't have furling issues before the new sails, and I didn't have the after even with the addition of battens.
I went with UK because they have a local rep to do the measuring.
I upgraded to tri-radial to hopefully keep the shape better as the sails age. I also added vertical battens on the main to resolve the flutter and get a little positive roach. I could not be happier. I can actually notice the boat respond to subtly changes in trim and she is much stiffer like the reviews said she was as "boat of the year". You won't regret the investment. I didn't have furling issues before the new sails, and I didn't have the after even with the addition of battens.
I went with UK because they have a local rep to do the measuring.
Furling mainsails do not trim out as well as a loose or shelf foot main. However, a well cut furling main can get your pretty close to a non racing level of sail trim that most of us would find acceptable. There is a cost for the convenience of mainsail furling... but the level of trim control has been rising as sail and equipment designers innovate and create. Inflatable battens for instance.
One other comment.... if you buy online from a reputable company, they will give you specific instructions on how to measure your boat for the sails you need. There are many options, not just for extras like draft stripes or windows, but for the actual sail shape you desire for your sailing style. You will learn a lot from the instructions and the loft's representative should be willing to discuss the pros and cons for the various shapes you may be considering. This knowledge is very important, even for just the casual weekender, because it makes you a better sailor which means you and your crew will be enjoying your boat as it was meant to be.
I just did this. Measured LP on existing sail and re-measured J. My LP/J shows about 119%, so call it 120%The very easiest way to determine sail size is to compare the headsail's Luff Perpendicular (LP) with the boat's (J)
LP is a perpendicular line from the sail'l luff through the clew of the sail. In geometric terms this line represents the height of a triangle and the sail's luff represents the its base
The J is the distance from the stemhead to the mast base... it is the foredeck length. It also represents one side of the right triangle created by the mast, deck and forestay.
Anyway, a comparison of the areas of these two triangles will give you a percentage number that represents the sail's size.
Sail area 110sq ft divided by foretriangle area of 100 sf = 110%
But WAIT.... did you forget your jr high school geometry?
The J is often stated with other common dimensions in the sales brochure or sailboatdata.com information sheet.
If the J is 10 and the LP is 11 then the size is 110.
Nerd alert. The amount of overlap depends on the shape of the sail. (high clew, low clew etc) So it is inevitable that a 100 % headsail will, in fact, have a clew that will overlap the mast.
Nerd alert 2..... the LP is NOT the same as a sail's FOOT.... don't blow it with the old salts by confusing the two.