RMG Sailwinches

RMG Smartwinch the Best winches on the market

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1/25 (36") Scale America's Cup high performance model sailboat

EC12 Meter

5ft Replica of the 1962 Americas Cup 12 Meter

Star 45

45" Scale Model of the Olympic Star Boat

J Class Boat-Shamrock V

1/16 (8'-10')Scale Replica of the 1930's America's Cup Class Yacht

RMG Sail Winches

High Performance sail control winches

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Chesapeake Performance Models is the authorized
North American service center for the RMG winches

  • Suitable for IOM to East Coast 12 meter Sailboats.
  • 4.8 to 7.2 volts nominal supply range.
  • Integral 5 Volt regulator for single battery operation.
  • Weight 4.8 oz.
  • Adjustable from 1 to 18 inches of travel with standard drum.
  • Failsafe shutdown when stalled.
  • Programmable for transmitter pulse width range
  • Static braking.
  • S.S. ball bearing on output shaft


What makes this winch smart is it's state of the art digital electronics controller. The controller is based on a Microcontroller Unit (MCU) which is a very small computer system in one chip. The MCU is controlled by a software program (ROM) which monitors all aspects of the winch's operation. Included in this program are some 'smart' fail-safe features that can protect the winch from problems that may occur with your yacht's electrics or sheeting system. To fit all the features into the controller, surface mount technology is used on a double sided printed circuit board
Dynamic Pulse Width Modulation
Servo systems use Pulse Width Modulation (PWM) to reduce power and speed as the desired position is approached. This gives finer and smoother control when small movements are required. But the problem with standard P.W.M. is that as the desired position is approached, the reduction in power can cause the servo to stop short. This can result in excess power consumption and. This is what's happening when a servo is not moving but is buzzing. However, unlike other winches and servos the SmartWinch has dynamic PWM. If the SmartWinch controller detects that it has not reached the desired position, power is increased up to 100% if necessary until the desired position is reached.
Stall Protection
When a conventional servo becomes stalled, it will stay stalled until the problem is solved. If not solved in time, the battery can be flattened, motor overheated, output transistors overheated and possibly damaged. But the SmartWinch knows when it is stalled and can protect itself by shutting down. The SmartWinch then signals that it is stalled by sounding a two-tone beep at 2 second intervals until reset. Stall mode can reset by moving the Tx stick in the opposite direction. If this does not work, turn the SmartWinch off and on again.
Battery Testing
The SmartWinch can monitor the battery for low voltage. If the voltage is below the warning level a warning signal (5 rising tones) will sound when the winch is switched on. If, during normal operation the voltage falls below the shutdown level, the winch will drive to the low battery failsafe position and hold there until the battery is replaced or voltage recovers. See Table 1. Default is battery monitoring OFF.
Low Battery Failsafe Position
The default low battery failsafe position is booms half out. But this is only true if using a standard spool type drum. If a spiral drum is used then this position would be closer to full in and could make it difficult to get the boat ashore. To compensate for this the low battery failsafe position is also adjustable so you can choose whatever position you wish between full in and full out.
Scaled Linear Travel
Travel response to the first 25% of Tx stick movement from full in when single ended or both ends when double ended is adjustable from 1:1 at minimum to a maximum of 4:1. For example, if 50% is selected, each increment of the first 25% of the stick range results in half the travel of the default setting. This feature is similar to exponential adjustment in a computer Tx. However scaled linear has the advantage of consistent incremental travel over the first 25% of stick movement whereas exponential is constantly varying. Default is 1:1.
Input Deadband
Input deadband is the amount dithering in the Rx signal that a servo can tolerate without responding to by constantly jittering. This is adjustable from 0.8 to 10 microseconds. Deadband adjustment allows the optimization of TX fine trim control. The default setting is 5 microseconds.
Voltage Protection
For protection of the electronics from over or under voltage conditions the circuit will disable itself when the supply voltage goes above 9 Volts or below 3.8 Volts.
Overrun Protection
Once set up to suit the transmitter, the winch is programmed to ignore signals which are above maximum and below minimum pulse width of that transmitter. This means that should interference cause the receiver to send signals outside the normal range for that transmitter, the winch will just ignore those signals. It will not try to travel closer than close hauled or beyond square running positions.



Smartwinch 280EL including 26Std Drum
Std 6 Turns (New EC12 Standard), Higher torque


  • Suitable for AC Class, J Class and larger boats.
  • 4.8 to 7.2 volts nominal supply range.
  • Integral 5 Volt regulator for single battery operation.
  • Weight 6.0 oz
  • Adjustable from 1 to 24 inches of travel with standard drum.
  • Failsafe shutdown when stalled.
  • Programmable for transmitter pulse width range
  • No over runs due to radio problems, interference etc.
  • Static braking.
  • S.S. ball bearing on output shaft



Smartwinch 380ES including 32Std Drum
Std 6 Turns (New EC12 Standard), Higher torque

All RMG Smartwinches are compatible with Spektrum Radios

Standard Drum Sizes

Tapered Spiral Drums

Item #32zs6
  • max diam 32 mm, 3 turns
  • min diam 12 mm, 1 turns
  • taper 2 turns
  • capacity 6 turns 480 mm

Cost $18.00

Item #45zs4
  • max diam 45mm, 2 turns
  • min diam 15 mm, 1 turn
  • taper 1 turn
  • capacity 4 turns 430 mm

Cost $20.00

Item #45zs9
  • max diam 45mm, 4 turns
  • min diam 15 mm, 1 turn
  • taper 4 turns
  • capacity 9 turns 1000 mm

Cost $22.00





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