Harken Blocks

With such a diverse range of hardware available, the Harken is here to help sort through the various options.

Planning entails determining which of your block hardware needs to be cleaned and serviced and which needs to be upgraded. Harken block range is so dependable and efficient, and we're here to help you decide which block you will need for each application and get your boat race ready for the season.

Here's a quick guide to which blocks you should be using:

  1. To avoid failures and ensure a long lifespan, make sure the block you choose works within its safe working load. Keep in mind that the angle of deflection around the sheave determines the loading of the block; a 60-degree deflection means the block receives 100% of the line load, whereas a 180-degree deflection means the block receives 200% of the line load. 
  2. There are various block designs to choose from, but it's crucial to make sure the block can align with the load of the line so that the ball bearings are loaded evenly and the line does not rub against the side plates, creating friction. The 29mm and 40mm ranges include swivel head and shackle variants for precise alignment, as well as fixed head designs for consistent alignment. The 57mm and 75mm swivel head versions include a locking pin to secure the shackle in place.
  3. While fixed head blocks are perfect for attaching to the stainless straps on your boat or spars for a maintenance-free solution, shackle attachments make rigging quick and simple. Tie-on blocks are also becoming more popular, and the Harken T2 range is an excellent lightweight solution. When using a tie-on product, make sure the attachment point on the boat is completely smooth and will not chafe through the rope.
  4. Blocks are frequently purchased in the smallest suitable size to ensure minimum weight and cost; however, increasing the sheave size will often greatly reduce friction, making systems more efficient. For instance, if the loads and rope size fall within the parameters of the block, 29mm blocks will frequently work for a dinghy's mainsheet system. However, 40mm blocks reduce friction for a system that is more responsive, quicker to ease, and requires less load to pull in.
  5. A key requirement, particularly with sheets, is the Line Diameter, which ensures that the sheave is wide enough to accommodate the diameter of the rope being used. A rope with a diameter that is too large will rub against the cheeks and head of the block, causing friction.
  6. It is essential to properly maintain your Harken blocks in order for them to last as long as they should. After sailing on seawater, make sure to rinse them thoroughly with fresh water and, if possible, wash them with warm soapy water. Use McLube's OneDrop Ball-Bearing Conditioner to reduce friction and repel dirt inside the block. Simply pour one drop of the conditioner into the ball-bearing race and spin the block until all of the surfaces are coated. It is critical not to use a dry lubricant on any ball-bearing blocks because it causes ball-bearings to skid rather than roll, resulting in flat-spots.
For more tips on Harken products please email Amanda@sailm8.com or call 805.930.9210
Reference: Sail-World