Dimensions of Offshore 31 (cheoy lee)

Updated 10/25/2012

Selected Measurements for Offshore 31 (cheoy lee)

BOAT	I	J	P	E	ISP	JSP	PY	EY	Disp	LWL	DRAFT
Offshore 31 (cheoy lee)	33	12.16	31	14	0	0	0	0	10500	23.33	3.67

Links to our Multi Vendor Used Sail Directory for Offshore 31 (cheoy lee)

Other Data Base Entries for offshore 31*

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BOAT	I	J	P	E	ISP	SPL	PY	PE	LWL	DRAFT	DISP
Cheoy Lee Offshore 31	33	12	30	13.5	33	12
Cheoy Lee Offshore 31 BS	33	14.4	30	13.5	33	14.4
Cheoy Lee Offshore 31K	31	9.5	27.5	13.2	31	9.5	18	8.8
OFFSHORE 31 (CHEOY LEE)	33	12.16	31	14					23.33	3.67	10500
OFFSHORE 31 BS (CHEOY LEE)	33	14.4	30	13.5					23.33	3.67	11000
OFFSHORE 31 KETCH (CHEOY LEE)	31	9.5	27.5	13.2					23.33	3.67	11000

Click Here for other boat types or to check dimensions from other data bases. We now offer three data bases.

Sail Area Calculations

BOAT	I	J	P	E	ISP	JSP	PY	EY	Disp	LWL	DRAFT
Offshore 31 (cheoy lee)	33	12.16	31	14	33	12.16	0	0	10500	23.33	3.67

The following formulas are approximate
Sail areas depend on lots of factors, leach hollow, foot round, luff hollow etc. Also, remember that jib sail area in general is based on the forestay length, I. But all things considered, these numbers are close but should not be considered exact. They are rules of thumb, not measurements of a this specific boat.

Mainsail

Mainsail = (P x E) / 2 = 217 sq ft
Racing Mainsail (add 10%) = 239 sq ft

Genoa

155% Genoa = (( J x I ) / 2) x 1.65 = 331 sq ft
135% Genoa = (( J x I ) / 2) x 1.44 = 289 sq ft

Jib

	_______
LP of full fore triangle = ( I x J ) / √	I² + J² = 11.4

Jib size to fill fore triangle = 94%
100% Jib = ( I x J ) / 2 = 201 sq ft

A more accurate LP calculator is HERE

Spinnaker

Spinnaker Area = Max Luff x Max Girth x ( 70-85%) = 512 to 622 sq ft
"Square" Spinnaker Area = Max Luff x Max Girth) = 731 sq ft
AC Area = 609 sq ft
Maximum Luff (.95 * sqrt (JSP^2 + ISP^2) = 33.41 feet
Maximum Girth = 1.8 * JSP = 21.89 feet
Ref

DEFINITIONS

"P" is the luff length of the mainsail, measured along the aft face of the mast from the top of the boom to the highest point that the mainsail can be hoisted or black band.

"E" is the foot length of the mainsail, measured along the boom from the aft face of the mast to the outermost point on the boom to which the main can be pulled or to the black band.

"I" is measured along the front of mast from the genoa halyard to the main deck. The main deck is where the deck would be if there were no deckhouse.

"J" is the base of the foretriangle measured along the deck from the headstay pin to the front of the mast.

"JSP" is the length of the spinnaker pole or the distance from the forward end of the bowsprit (fully extended) to the front face of the mast.

"ISP" is measured from the highest spinnaker halyard to the deck.

"PY" and "EY" are, respectively the luff length and foot length of the mizzen of a yawl or ketch measured in the same way as for the mainsail.

"IY" is the measurement from the staysail halyard to the deck.

"JY" is the measurement from the staysail stay to the front face of the mast.

"LP" is the shortest distance between the clew and the luff of the genoa.

Data*

This data is supplied as a reference and all boat dimensions should be verified before using it in any critical application.
The information in these data bases is a starting point. There are errors as you can see as the different data bases do not always agree. In addition, some boats have been modified from stock and will not match the data in these databases. None of this data has been checked by L-36.com so please always check your boat before relying on this data.
Data is from a variety of sources.

db = SBD is used under the Creative Commons License sailboatdata.com (sailboatdata.com) / CC BY 3.0

db = PHRF is the PHRF Critical Dimensions database
db = WEB is the commonly available data found on many web sites
db = BIG is a combination of all of the above.

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