Measurement | Lean Sails

Step 2 · Measurement

Measuring your boat

When we produce your new sails, we need a set of measurements. You can take them yourself, or get help from us. If you choose to measure the boat on your own, the videos below walk you through doing it in the best possible way.

Sail type:

Boat & Owner

Name *

Email *

Telephone (optional)

Boat type *

Sail number

Mast & boat measurements

Measured in metres

Max luff PM *

Along the mast, band to band

Max foot EM *

Along the boom

Leech AL

Only if sprayhood clearance needed

Mast to backstay C

Aft edge of the mast

Gooseneck — mast × boom

Tack pin & reef tack · measured in mm

Mast → tack pin X1

Boom → tack pin X2

Feed-in height Y

Mast → reef tack Z1

Boom → reef tack Z2

Slides

Does one of these match yours?

Matching slide type *

	Type	Ref	X	Y1	Y2	Z1	Z2
	None / not sure	—	—	—	—	—	—
Flat plate · round foot
	HA158	A016	22	29	9	8	3
	HA258	A017	50	40	11	14	3
	HA358	A018	22	30	12	12	3
Base plate · raised loop
	HA89	A007	32	21	4	15	7
	HA90	A008	35	23	4	18	9
	HA91	A009	39	25	5	21	8
Hole plate · flared foot
	HA458	A014	35	29	6	13.8	4
	HA558	A013	25	22	3	10.5	4

All dimensions in mm — X width · Y1 overall height · Y2 lower height · Z1 foot · Z2 top hook. Pick the closest match, or send a photo of one of your slides.

Photos & notes

Please add 3 photos: the tack (boom meets mast), the clew (boom end), and the boat seen from the side.

Boat & Owner

Name *

Email *

Telephone (optional)

Boat type *

Sail number

Mast & boom measurements

Measured in metres · halyard full up, sail full out

Max luff Pmax *

Tack attachment to head swivel attachment, halyard full up

Max foot Emax *

From the aft face of the furling profile inside the mast to full out on the boom

Mast groove & headfoil

Measured in mm

Cutback CB

Tack attachment to the mast groove

Headfoil tape size Ø

Diameter of the luff tape

Headfoil stop S

Height of the stop above the boom

Photos & notes

Please add 3 photos: the mast groove at the tack, the clew (boom end), and the boat seen from the side.

Boat & Owner

Owner name *

Email *

Boat make & model

Sail number

Home port

Halyard Measurements

Hoist the spinnaker halyard to maximum, then measure

Before measuring: Hoist the spinnaker halyard fully. Measure from the sheerline (hull/deck join) — NOT the top of any cabin or deckhouse.

Halyard height ISP *

Top of halyard to sheerline

Top to tack A *

From the top to the tack attachment

Top to block B

To sheet block outside shrouds

Drop the halyard, then measure from the tack attachment

Tack to mast face TPS

Distance to the front face of the mast

Tack to sheet block C

Passing outside the shrouds

Notes

Boat & Sail Info

Owner name *

Sail number

Boat type *

Home port

Important: Lay the sail flat on a clean surface. Pull the luff tight — ideally with a tackle or helper. Measure along the edges, not across the fabric.

Overall Dimensions

Luff pulled tight. Measure along each edge.

Luff *

Leech *

Foot *

Headboard width HB

Width of the headboard at the head

Sail offset

Edge of sail to batten car bearing point

Mid-Girth Measurements

Measured perpendicular to the luff at each height

Top girth MGT

At ¾ luff height

Upper girth MGU

At ½ luff height

Mid girth MGM

At ¼ luff height

Reefing

1st reef height

2nd reef height

3rd reef height

Reef back

Aft mast face to reef point on boom

Tack back

Aft mast face to tack attachment

Luff Track & Foot

Luff fitting type *

Plastic slugs

Cars / sliders

Groove (rope luff)

Piston hanks

Foot type

Loose foot

Boom groove

Cord stop at tack

Photos Required

📷

Slides / Cars

Close-up of luff track

📷

Class Badge

Logo or insignia

📷

Full Sail

Whole sail laid flat

Boat & Owner

Measuring a furling headsail

Name *

Email *

Telephone (optional)

Boat type *

Home port

Furler & set-up

How the furler drum is mounted changes measures C, D & U

Furler drum mounting *

Over deck

Under deck

Over-deck = drum sits on deck. Under-deck = drum recessed below deck, foil exits at deck level.

Furler brand / model

Furling direction

Sail number

Step 1 & 2 · Halyard hoisted

Luff & hoist measurements

Measured in metres

Before you start: tie a long tape to the lowest shackle of the furler halyard swivel and set the backstay to 50% of maximum. Hoist the tape as far as it will go.

Max luff A *

To the furler tack attachment (with swivel)

Max hoist B

Halyard alone, no swivel, to tack attachment

Forestay length C

To the lowest pin bolt on the forestayTo deck height at the forestay

Halyard height D

To deck height at the cap-shroud position

Leech — fwd E

To the forward end of the sheet track

Leech — aft F

To the aft end of the sheet track

For E and F the tape may need to pass outside the mast’s cap shroud, like the leech of a genoa.

Step 4 & 5 · Halyard down

Deck & sheeting geometry

Tape fixed to the forestay’s lowest pin boltdeck height at the forestay

“J” measurement J *

To the front of the mast at the top of the coachroof

Cap-shroud position K

To the cap-shroud fitting in the deck

Sheet track — fwd end L

Sheet track — aft end M

Step 5 · Sheeting angles from the boat’s centreline

Angle — fwd N

Fwd end of track to centreline

Angle — aft O

Aft end of track to centreline

Cap shroud Q

Cap shroud to centreline

Step 6 · Furler details

Tack, feed-in & luff tape

Measured in mm

Tack cutback R

Tack shackle to aft edge of the forestay profile

Sail feed-in S

Tack attachment up to the feed-in in the profile

Luff-tape thickness T

Max thickness fed into the forestay profile

Step 7 · Waterline

Water-surface heights

Used to set trim-stripe & seam angles to the horizon

Forestay U

Lowest pin boltDeck at forestay to the water surface

Cap shroud V

Cap-shroud fitting to water surface

Sheet track X

Fwd end of track to water surface

UV cover & notes

UV protection fitted on

Starboard

Port

None

Boat & Owner

Measuring a hanked headsail

Name *

Email *

Telephone (optional)

Boat type *

Sail number

Foretriangle

Measured in metres

Foretriangle height I *

Deck to forestay at the masthead

Foretriangle base J *

Forestay to front of mast at deck

Luff length LU

Along the forestay, tack pin to halyard

Tack height TH

Deck to the tack fitting eye

Luff attachment & overlap

Luff attachment *

Piston hanks

Plastic hanks

Rope / groove

LP overlap (if known)

Longest perpendicular — luff to clew. Leave blank if unsure.

Sheet leads

From the boat’s centreline · metres

Lead — fwd end

Lead — aft end

Lead to centreline

Notes

Add photos of the tack fitting, the head fitting and the boat from the side so the loft can confirm the geometry.

Boat & Sail Info

Copying an existing headsail

Name *

Boat type *

Date

Sail number

Order number

Measured by

Measure along the edges, corner to corner — from the bearing point of the webbing loop or ring at the tack and head. Stretch the luff tight with a tackle: an old luff rope has usually shrunk.

Edge lengths

Measured in mm

Luff LU *

Tack to head

Leech LE *

Head to clew

Foot FO *

Tack to clew

Luff tape & furler

So the new luff feeds your existing foil

Luff-tape Ø Ø

Luff-tape diameter

Cutback CB

Tack ring to start of the luff tape

Headfoil stop S

Apex to the head foil stop

Furler brand / model

UV cover

UV protection fitted on

Starboard

Port

None

Photos & notes

📷

Tack

Ring / webbing & furler drum

📷

Head

Swivel & luff tape

📷

Full Sail

Whole sail laid flat

Boat & Sail Info

Copying an existing hanked headsail

Name *

Boat type *

Date

Sail number

Order number

Measured by

Measure along the edges, corner to corner — from the bearing point of the ring or webbing loop at the tack and head. Stretch the luff tight with a tackle: an old luff wire or rope has usually stretched or shrunk.

Edge lengths

Measured in mm

Luff LU *

Tack to head

Leech LE *

Head to clew

Foot FO *

Tack to clew

Luff & hanks

So the new sail hanks onto your forestay

Hank type HK

Type & size of the existing hanks

Number of hanks

Count along the luff

Luff finish

How the luff is made up

Head & tack fitting

UV cover

UV protection fitted on

Starboard

Port

None

Photos & notes

📷

Tack

Ring / webbing & tack hank

📷

Head

Head ring & top hank

📷

Full Sail

Whole sail laid flat

Boat & Sail Info

Copying an existing Code 0

Name *

Boat type *

Measured by

Lay the sail flat and pull the luff really tight, ideally with a tackle — a Code 0 luff carries a cable or heavy rope that must be measured under tension.

Edge lengths & girth

Measured in mm

Luff LU *

Head to tack, pulled tight

Leech LE *

Head to clew

Foot FO *

Tack to clew

Mid-girth MG

At half luff, luff to leech

Luff-tape / cable Ø

Diameter of the luff cable or tape

Corners & furler

Tack / head fittings

Soft loops

Rings

Furler swivels

Top-down furler brand / model

Photos & notes

📷

Tack

Fitting & furler drum

📷

Head

Swivel & top fitting

📷

Full Sail

Whole sail laid flat

📋

Form in preparation

This measurement form is being finalized by the loft. It will be available soon.

Your progress is saved automatically every 2 minutes

General

Tips for measuring

This video gives general tips for taking measurements — no matter what you need to measure. Pick a calm day, bring a tape measure and folding ruler, and take your time.

Headsail

Headsail measuring

Order a headsail and measure it yourself, and you’ll receive a measurement form to fill out. The form varies slightly with your boat and the headsail you’ve chosen. Here you can see how we measure a typical furling genoa or furling jib.

Mainsail

Mainsail measuring

Order a mainsail and measure it yourself, and you’ll receive a measurement form to fill out. The form varies slightly with your boat and the mainsail you’ve chosen. Here you can see how we measure a typical mainsail.

Measuring your boat

Form in preparation

Tips for measuring

Headsail measuring

Mainsail measuring

Contact

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