Harken: Ordering Midrange Blocks

Ordering Midrange blocks

1.Determine block size and type
The tables below are guidlines for typical applications. Additional rigging tips are available at http://www.harken.com

2. Contact
If you have any questions, please contact your dealer or Harken Technical Service.

Note: Multihulls and heavy displacement monohulls should reduce the maximum sail areas shown by as much as 25%.

Technical Service:
Email: Harken Technical Service
262-691-3320 phone 7:30-4:30 CST

MAINSHEET	MAST BASE
GENOA	RUNNING BACK STAY
SPINNAKER	VANG

Mainsheet
The farther forward a mainsheet system is on the boom, the higher the loads. Systems with multiple attachment points spread the load over the boom. Use the table below to determine if Midrange blocks are strong enough for you mainsail area.

		Maximum mainsail area *(P x E x .5 x 1.1)**
		ft²	m²

End-Boom System	Single Attachment	500	46

	Multiple Attachment*	540	50

Mid-Boom System	Single Attachment	425	39

	Multiple Attachment	500	46

*Assumes 10% roach			*Assumes more than one load-carrying shackle on the boom and traveler car or deck.

Genoa Footblocks
Determine the area of your foretriangle and how many degrees the footblock will deflect the line to select footblock size. For system loading details, see the Block Loading vs. Angle of Deflection and Genoa System Loading sections.

Turning Blocks		Maximum 100% foretriangle sail area at 35 knots (I x J x .5)

	180° Turn	150**	14**

Turning Blocks

	90° Turn	215	20

Spinnaker: Symmetrical/asymmetrical
Use the spinnaker's sail area to determine what size Midrange or high-load Midrange blocks to use for the sheet and afterguy controls.

		Maximum spinnaker area P x E x .5 x 1.8
		Standard blocks		High-load blocks
		ft²	m²	ft²	m²

Sheet Blocks	Plain	1100	100	1300	120

	Ratchet	900	83	-	-

Afterguy Blocks**	Mounted Amidships	1100***	100***	1250***	115***

	Mounted on Transom	900	83	1000	93
	Maximum "I" dimension



Masthead Halyard Block		48 ft	14.6 m	53 ft	16 m

***Assumes maximum deflection of 45°

Mast Base Lead Blocks
Attach blocks to padeyes or 1634 Midrange ESP stand-up bases, or mount mastbase halyard leads to the deck. Use mainsail luff length and foretriangle height to determine what size Midrange or high-load Midrange blocks to use. Carbo blocks or1986 mastbase halyard leads may be appropriated for applications with lower loads.

	Maximum "P" dimension
	Standard blocks		High-load blocks
	ft	m	ft	m

Main Halyard Lead Block	48	14.6	52	15.8

	Maximum "I" dimension

Genoa Halyard Lead Block	46	14	50	15.3

	Maximum "I" dimension

Spinnaker Halyard Lead Block	48	14.6	53	16

Running Backstays
The table below shows if Midrange of high-load Midrange blocks are strong enough for your backstay, based on the breaking strength of your runner wire.

		Maximum breaking load of runner wire
		Standard blocks		High-load blocks
		lb	kg	lb	kg

Flying Block	2:1	3600	1633	4600	2086

Afterguy Blocks	1:1	2200	998	2800	1270

	2:1 Becket	3600	1633	3600	1633

	2:1 Single	4500	2040	5000	2268

Vang
Common vang configurations

	Maximum mainsail area P x E x .5 x 1.1
	ft²	m²

Fiddle Blocks	400	37

Triple Blocks	450	42


*Assumes 10% roach