Measure Mainsail 2025 | Kraken Sails

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Sail Basics

This allows us to work out which questions to ask you during the measure. If at any point you'd like to leave the form and come back to it later, pressing save for later will email you a link you can come back to for 30 days.

Who is doing the measure today?

(Your name, it's not always the boat owner)

Phone

Boat Name

Sail Number

Class / Make / Model

Ratings & One-Design

Are we building to one-design rules?

Yes, absolutely to class rules

No, design the best sail for my boat

Unsure, please discuss

Are we building to a current Handicap or Rating

If you don't want to re-submit (and pay for) a new or amended handicap you may want us to build to the existing

Build To Existing

Build the Best Sail

Unsure, please discuss

Do you intend to keep your rigging the same for this new sail?

Sometimes our customers want to switch to a square top or make other changes. If so, you can let us know here and we'll ask further questions in design. Answer all of today's questions as the boat is today.

Yes, keeping everything the same

No, plan to make major changes

No, plan to make minor changes

Do you have a backstay?

Yes Backstay Adjustable (hydraulics or sheeting)

Yes Backstay Fixed

No - Running Backstays

Do you have a 'black band' for handicap or class

This is the black band at the top of your mast, you may be able to hoist your halyard past it.

Yes - Black Band

No - No Black Band

Halyard Measurements

Please Check

Take a moment to make sure your boom is at the height you like it before performing the following major measurements.

Use Kicker/Vang/Topper to elevate your boom to the preferred operating height. Having the boom to high or to low will impact your leech measurements.
Move your outhaul car to it's most aft/longest position (you may want to remove your clew attachment at this point).
Make sure your measuring tape can take a straight path to the outhaul attachment.

Boom Position Confirmation*

I am happy with my boom position

P - Max Luff (meters to 2 decimals)

Connect the tape to the main halyard and hoist to max height. Measure to the top surface of the boom.

Max Leech (meters to 2 decimals)

From Max Hoist, with the boom at the correct height, and the outhaul at max length, measure max leech length, distance from max hoist to the bearing point of your outhaul.

P (Black Band) - Max Luff (meters to 2 decimals)

Now hoist so that the halyard is at the black band height. Measure to the top surface of the boom.

Max Leech Black Band(meters to 2 decimals)

With the halyard still at the Black Band height, with the boom at the correct height, and the outhaul at black band length, measure max leech length

Boom Length Measurements

All measurements are taken from the back surface of the mast. If you have an external mast track, they're still taken from the back surface of the mast.

Boom Length Overall

Back of mast to longest point of boom. This helps us with clearance of backstay.

Boom to Backstay

Gap between the end of the boom and the backstay. Measure the distance from the longest (most aft) point of boom to backstay.

E - Max Foot

This is the distance from the back surface of the mast, to the bearing point of the outhaul when it is at maximum length. This should be the same setting you used for max leech.

Max Foot Black Band

This is the distance from the back surface of the mast, to the bearing point of the outhaul when it is at black band length. This should be the same setting you used for max leech.

Main Tack

Tack height and set back allow us to centre the tack attachment on your new sail perfectly in space.

Photo of Tack Area

For context, let's start with a tack photo. If your sail is stacked, do your best. Try to include from the mast gate (if you have one), down to the top surface of the boom and include the tack attachment point. Take a couple of photos if that's easier.

Drop files here or

Max. file size: 4 MB, Max. files: 3.

Main Sail Tack Attachment

How does the tack of your mainsail attach to your rigging?

Shackle

Snap Shackle

A - Tack Set Back (mm)

Height from back surface of mast to the tack bearing point. Steel Ruler - Measure from the back edge of your mast to the tack shackle pin under a bit of tension as if the sail were hoisted. If you have an external mast car track, still measure from the back surface of the boom.

B - Tack Set Up (mm)

Height from top surface of boom to pin. Steel Ruler - Measure from the top of your boom to the tack pin height. This means, when the sail is hoisted where the shackle pin would naturally seat on the sail fitting.

D - Mast Track Gate Entry Height from boom (in mm)

Measure the height from the top surface of the boom/gooseneck to the top opening of the mast gate. This allows us to tailor the sail tack nicely.

How does your main foot attach to your boom?*

Loose (Along Foot)

Bolt Rope

Slugs/Sides

E - Boom Track Gate Entry Set Back (in mm)

Distance from the back surface of the mast to the opening of the boom track gate in mm.

Reefing & Cunningham

How Many Reefs For this Main We're Building

You may have more or less than the current main based on the application of the new sail.

Unsure, let's discuss

No Reefs

1 Reef

2 Reefs

3 Reefs

Which Side Does Your Cunningham Attach

Starboard Side Only

Port Side Only

Both Sides

Photo of Cunningham Attachment.

A picture tells a thousand words, take a quick picture of your cunningham attachment.

Max. file size: 256 MB.

Current Cunningham Attachment Type

If you've taken a good photo and you're unsure, leave this blank.

Loop Attachment

Cringle (Steel Ring creating a hole through sail)

Soft Loop Attachment

Other

Photo of Reef Attachment.

A picture tells a thousand words, take a quick picture of your reef attachment.

Max. file size: 256 MB.

Current Reef Attachment Type

If you've taken a good photo and you're unsure, leave this blank.

Dog Bone

Webbing Loop Attachment

Cringle (Steel ring creating a hole through sail)

Other

Dog Bone Width

Length of webbing between dog bone rings.

Dog Bone Ring Diameter

The diameter of the dog bone rings.

C - Reef Point Set Back (mm)

From Back of Mast to loading point of reefing point. Find a reefing point, and measure from the back surface of the mast to the bearing point of the reef. This might be where the hook for the cunningham would sit, or it might be where the middle of the dog bone sits within the sail.

Luff Attachment

How does your main luff attach to your mast?

Bolt Rope

Slides / Slugs

Cars

External Car Rail

A combination of Cars and Slides/Slugs

Other

Slug At Top

Would you like a slug at the top (head) of your main, or leave luff bolt rope only.

Yes - Slug at top

No - Bolt Rope Only

Unsure - Please discuss at design

Will you measure the slides/bolt rope, or the track

While you can measure the internal track diameter, or the slug/rope, knowing which one you used helps our numbers.

Will Measure A Slug/Slide/Car

Am Measuring the Track Internals

Base Width of Slide or car

(Leave blank if you have a bolt rope with no slugs) This is the widest part of the car or slug as it sits in the mast track. If it's a round slug, then it will be the diameter of the slug. If it's a flat based slug, then it will be the maximum width of the base.

Slug / Slide Neck

This is the width of the neck of the slide as it comes out of the mast. (Leave blank if you have a bolt rope with no slugs)

Luff Rope Diameter (mm) (if using luff rope)

Please also note if you used a drill bit to size the track, or calipers to measure the luff rope.

Any identifying marks on your slides, slugs and/or cars?

If you have identifyling marks on the slides or slugs, including brands and or code numbers, please put them here.

Luff Set Back Photo

If you have slugs or cars on your mainsail, please take a photo with a ruler of the back of your mast to the leading edge of the sail cloth as it would be if hoisted.

Max. file size: 256 MB.

Luff Set Back

If you have slugs or cars, please measure the distance from the back surface of the mast to the leading edge of the sail fabric.

How does your Mainsail Clew Attach?

Clew Strap

Track and Pin

Slug and Pin

D -Clew Attachment Inner Width (mm)

This is typically the inner width of the shackle that holds the sail to the outhaul. Calipers/Steel Ruler - Please measure the inside gate of the shackle that attaches to your clue. This width allows us to make sure your exisiting hardware will be compatible with the sail hardware & thickness.

Boom Circumference

What is the circumference of your boom. This will allow us to build you a custom clew strap for your boom.

Clew Photo

Please take a side on photo of your boom with clew attached. Frame the photo to include; the end of the boom, the underside of the boom, and the corner of the sail all in the same shot if possible.

Drop files here or

Max. file size: 5 MB, Max. files: 3.

Mast Bend

To generate a correct Luff Curve, we take a side on image of your boat and map a 2D luff curve. Find a place to get side on to your boat, perpendicular to the mast. It's ok if it's at the marina and there are other masts in the image.

No Backstay Tension

Take a photo of your mast with no backstay (just pre-bend). Upload a couple of photos if you're not sure.

Drop files here or

Max. file size: 256 MB, Max. files: 3.

Max Backstay Tension

Tension your mast to Max Backstay, (max bend), and take a photo side on.

Drop files here or

Max. file size: 256 MB, Max. files: 3.

Average Backstay Tension

Finally, tension your back stay to your average setting (what you might have on in 12 knots), and photograph.

Drop files here or

Max. file size: 256 MB, Max. files: 3.