Klacko Marine Technical Guide
6:1 Mechanical Advantage
Recommended Hardware: Harken 57mm Carbo Series
To replicate the low-friction retrieval shown above, we specify the Harken AirCarbo series. These ball-bearing blocks are designed to handle high static loads without the “binding” typical of standard sheaves.
Harken #2604
57mm Carbo Single/Swivel. High-strength sideplates for primary load bearing.
View Tech Specs →Harken #2605
57mm Carbo Single/Swivel/Becket. The anchor point for the multi-part purchase.
View Tech Specs →Harken #2615
57mm Carbo Fiddle/Swivel. Provides a streamlined, vertical tackle arrangement.
View Tech Specs →Reeving Instructions: 6:1 Purchase
Configured for Harken #2605 and #2604 Blocks
- Anchor: Secure line to the Becket on the top #2605 block.
- Lead line down to the first sheave of the bottom #2604 block.
- Return to the top and pass over the first sheave of the #2605.
- Lead down to the second sheave of the bottom block.
- Return to the top and pass over the second sheave of the #2605.
- Lead down to the final sheave of the bottom block.
- Exit: Pass through the final top sheave to create the Hauling Part.
Physics of the Lift
Lifting a 250lb tender shouldn’t feel like a 250lb task. By integrating a 6:1 mechanical advantage system, we reduce the required pull-force to a fraction of the total weight.
Our bridles utilize 5/16 Double Braid line, which offers a strength-to-weight ratio superior to steel cable with low stretch.
