44 P E I J Ordering Big Boat Blocks Mainsheet Mainsheets are usually attached near the end or the middle of the boom, depending on accessibility and whether the boat is used for racing or cruising. The farther forward a mainsheet system is on the boom, the higher the loads it sees. Systems with multiple attachment points spread the load over the boom. Use the table to choose the appropriate Black Magic, Element, or stainless steel blocks for your main- sail area. See pages 262-263 for common configurations. Running Backstays Crews use running backstays to adjust mast bend for different wind conditions. This controls headsail sag as well as the camber (depth) of the mainsail. Use Black Magic Air Runner blocks with higher breaking strengths than your runner wire. Mastbase Lead Blocks Leading halyards and control lines aft allows crews to raise and lower sails or make tuning adjustments from the cockpit. Attach blocks to the mast collar post or padeyes, or mount mastbase halyard leads to the deck. The table below sizes Black Magic, Element, ESP, stainless steel, and mastbase blocks for different foretriangle heights and luff lengths. See page 268 for common configurations. 1. Determine block size and type The tables below are a guideline 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: These hardware specifications assume a boat of moderate displacement sailing in normal conditions. Ultralight displacement boats (ULDB) may use smaller hardware. Heavy displacement boats and multihulls often require stronger hardware. Maximum mainsail area (P x E x .5 x 1.1**) 45 mm Element* 57 mm low-load Black Magic 60 mm Element* 57 mm high-load Black Magic 75 mm low-load Black Magic/ 75 mm ESP 80 mm Element* 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 ft 2 m 2 ft 2 m 2 ft 2 m 2 ft 2 m 2 ft 2 m 2 ft 2 m 2 ft 2 m 2 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 *Element blocks are appropriate for most cruising boats. For high-performance boats, choose Black Magic blocks. **Assumes 10% roach. ‡Assumes two or more shackles share load on both boom and deck. 45 mm Element* 57 mm low-load Black Magic/ESP 60 mm Element* 57 mm high-load Black Magic/ fi xed MBL** blocks 75 mm low-load Black Magic/ Mast collar post block/ 75 mm ESP 80 mm Element* 75 mm high-load Black Magic/fi xed 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 *Element blocks are appropriate for most cruising boats. For high-performance boats, choose Black Magic blocks. **MBL = Mastbase lead blocks. Maximum breaking load of runner wire 57 mm Black Magic Air Runner 75 mm Black Magic Air Runner 100 mm Black Magic Air Runner 125 mm Black Magic Air Runner 150 mm Black Magic Air Runner lb kg lb kg lb kg lb kg lb kg Flying 2500 1134 10000 4535 15000 6800 22000 10000 30000 13605 2:1 Separate deck 3025 1372 12100 5490 17550 7960 26500 12020 36136 16388 2:1 Becket deck 1875 850 7500 3400 10900 4945 16500 7485 22500 10204 3:1 Deck (block #1) 3713 1684 14850 6735 21600 9800 32700 14835 44550 20203 3:1 Deck (block #2) 4525 2052 18100 8210 26300 11930 39850 18075 54300 24625
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