As one step in the maintainance proceedure of my Side power bow thruster it is recommended to re-torque the bolts. The manual reccomends a force of 12.4 ft/lbs. To access these bolts it will be necessary to use an 18" long x 1/2" extension on my torque wrench. A formula exists to adjust the torque values for the length of extension. Does anyone have this formula ?