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Harken Big Boat Blocks Use Chart
Go to: Harken Blocks \| Big Boat Blocks \| Use Harken Big Boat Chart

- Mainsheet
- Running Backstays
- Mastbase Lead Blocks

- Spinnaker: Symmetrical / Asymmetrical
- Genoa: Adjustable Lead Car

- Single Genoa Foot Blocks
- Double Genoa Foot Blocks

Mainsheet: Find here your sailboat rig dimensions and how to calculate sail areas.
											Maximum mainsail area
Description		57 mm Low-load Black Magic					57 mm High-load Black Magic					75 mm Low-load Black Magic/75 mm ESP									75 mm High-load Black Magic/75 mm ESP									100 mm Black Magic/100 mm Stainless								125 mm Black Magic							150 Black Magic/150 mm Stainless
		ft2			m2		ft2			m2		ft2			m2					ft2					m2					ft2				m2				ft2			m2				ft2				m2

End-boom
Single Attachment	450				41		550			51		600				56					750				70					900				84				1250			116				1550			144
Multiple Attachment	500				46		675			63		720				67					900				84					1100				102				1500			139				1750			163
Mid-boom
Single Attachment	400				37		400			37		450				42					550				51					700				65				1000			93				1375			128
Multiple Attachment	450				41		575			53		600				56					700				65					950				88				1300			121				1525			142
** Safe working loads and breaking strengths for blocks based on cam strengths Top
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Running Backstays: Find here your sailboat rig dimensions and how to calculate sail areas.

								Breaking strength of runner
Description							3" Stainless steel runners.											4" Stainless Black Magic												5" Stainless Black Magic											57 mm High-load Black Magic
							lb					kg						lb						kg						lb						kg					lb					kg

Flying Blocks							10000					4535						12500						5670						19000						8618					2500					1134
2:1 Separate Deck Blocks							12100					5490						15250						6920						23150						10500					3025					1372
2:1 Becket Deck Blocks							7500					3400						9470						4295						16500						7485					1875					850
3:1 Deck Blocks (Block # 1)							14850					6735						18750						8505						28500						12928					3713					1684
3:1 Deck Blocks (Block # 2)							18100					8210						22875						10375						34750						15760					4525					2052

Description							75 mm Black Magic											100 mm Black Magic												125mm Black Magic											150 mm Black Magic
							lb					kg						lb						kg						lb						kg					lb					kg
Flying Blocks							10000					4535						15000						6800						22000						10000					30000					13605
2:1 Separate Deck Blocks							12100					5490						17550						7960						26500						12020					36136					16388
2:1 Becket Deck Blocks							7500					3400						10900						4945						16500						7485					22500					10204
3:1 Deck Blocks (Block # 1)							14850					6735						21600						9800						32700						14835					44550					20203
3:1 Deck Blocks (Block # 2)							18100					8210						26300						11930						39850						18075					54300					24625

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Mastbase Lead Blocks : Find here your sailboat rig dimensions and how to calculate sail areas.
Description			57 mm Low-load Black Magic/ESP							57 mm High-load Black Magic & fixed MBL blocks								75 mm Low-load Black Magic & Mastcollar post block/75 mm ESP										75 mm High-load Black Magic & fixed MBL blocks/75 mm Stainless									100 mm Black Magic/100 mm Stainless								125 mm Black Magic
			ft			m				ft			m					ft					m					ft				m					ft			m					ft			m

			Maximum "P" Dimension
Main Halyard			47			14.3				52			15.8					60					18.3					74				22.6					80			25					90			27.5
			Maximum "I" Dimension
Genoa Halyard			45			13.7				50			15.2					58					17.7					72				21.9					76			23.2					87			26.5
Spinnaker Halyard			47			14.3				53			16.1					60					18.3					74				22.6					82			25					93			28.4
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Spinnaker: Symmetrica / Asymmetrical: Find here your sailboat rig dimensions and how to calculate sail areas.
				Maximum spinnaker area
Description				57 mm Low-load Black Magic					57 mm High-load Black Magic					75 mm Low-load Black Magic/75 mm ESP									75 mm High-load Black Magic/75 mm Stainless							100 mm Black Magic/100 mm Stainless								125 mm Black Magic							150 mm Black Magic/150 mm Stainless
				ft2		m2			ft2			m2		ft2					m2				ft2				m2			ft2				m2				ft2			m2				ft2			m2

Spinnaker Sheet, T.L.				720		67			1200			111		1400					130				2000				186			2650				246				4300			400				5600			520
Afferguy				790		73			1320			123		1500					140				2200				204			2900				269				4700			437				6100			567

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Genoa: Adjustable Lead Car: Find here your sailboat rig dimensions and how to calculate sail areas.
				Maximum sail area
Description				Smal Boat							Midrange									Big Boat 3000											Big Boat 4500											Mini- Maxi
				ft2			m2				ft2					m2				ft2						m2					ft2						m2					ft2				m2

# 1 & # 2 Genoa*				450			41				750					70				1500						139					2700						251					4400				409
# 3 Genoa**				175			16				330					31				435						40					650						60					1300				121
* Assumes 155 % Genoa/25 knots apparent wind/45º sheet lead angle. ** Assumes 100 % Genoa/40 knots apparent wind/60º sheet lead angle.
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Single Genoa Foot Blocks: Find here your sailboat rig dimensions and how to calculate sail areas.
				Maximum 100% foretriangle sail area at 40 knots
Description				57 mm Low-load Black Magic						57 mm High-load Black Magic							75 mm Black Magic/75 mm Stainless									100 mm Black Magic/ 100 mm Stainless									125 mm Black Magic									150 mm Black Magic/150 mm Stainless
				ft2		m2				ft2			m2				ft2					m2				ft2					m2				ft2				m2					ft2				m2

180º Turn				110		10				180			17				365					34				540					50				800				74					1100				102
120º Turn				125		12				210			20				420					39				630					59				920				85					1256				117
90º Turn				155		14				260			24				515					48				770					72				1130				105					1540				143

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Double Genoa Foot Blocks: Find here your sailboat rig dimensions and how to calculate sail areas.
				Maximum 100 % foretriangle sail area at 40 knots
Description				57 mm Low-load Black Magic								57 mm High-load Black Magic											75 mm Black Magic										100 mm Black Magic										125 mm Black Magic
				ft2				m2				ft2						m2					ft2						m2				ft2					m2					ft2				m2

180º Turn				75				7				120						11					240						22				360					33					530				49
120º Turn				85				8				140						13					275						26				415					39					610				57
90º Turn				105				10				175						16					340						32				510					47					750				70

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Harken Big Boat Blocks

If you need immediate assistance finding the appropriate sailing gear, sailboat hardware or sailing equipment for your boat, please call us toll free at: 1-888-756-8883, our crew is ready to help you.

Pictures and text courtesy of Harken Sailboat Equipment

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