RT Steel-Bolted Rubber Couplings



The RT bolted rubber flexible coupling, most often used aft of the gearbox, provides dynamic mobility to a resiliently-mounted engine and minimizes bending stresses in the gearbox output shaft. Additionally, the RT coupling here has significant mechanical and acoustic attenuation, keeping engine and gear noise away from the low-speed shafting and bearings. Dynamic Magnifier values as low as 3.5 can be provided with high-damping elastomer elements.

  • Two-directional (propeller) thrust capability
  • Two-directional torque capability
  • Low torsional, angular and radial stiffness for torsional tuning, misalignment and shock absorption
  • Excellent noise-attenuating properties
  • Good mechanical damping level
  • Open design, facilitating inspection and maintenance and providing for cool operation
  • Equal axial (longitudinal) stiffness for forward and reverse thrusts for solid-body-frequency calculations
  • Lubrication not required
  • A.B.S. & Lloyds Registry approved
  • Shock tested to U.S. MIL spec MIL-S 901C (MOD.)


Bolted-rubber RT couplings – normally used behind reduction gear boxes (as in the Soft-Mount package) to reduce propulsion engine and gear noise penetrating the shaft line, bearings and hull, also to co-operate with the vibration isolators below engine/gear. Carries propeller thrust in both directions.Torque Limiters can be combined with RT or SS couplings to provide a fail-safe shock absorbing/release device for boats operating in ice.

RT-Couplings Specifications

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