The short answer
Choose the mechanical point to measure first. Smartlink inserts between two compatible links, Smarttune replaces a standing-rigging turnbuckle, Smarttoggle works between a furler and a flying sail's cable; load pins and Smartbatten answer other geometries. Only then check the working load, diameters, threads, pins, orientation, accuracy range, display interfaces and maintenance constraints of the exact reference. A load sensor does not strengthen the rig and does not define its safe limit: admissible values remain those of the architect, the rigger and the structural components.
Start from the sailing question
A useful measurement answers a clear decision: recover a rig tension, compare a setting, monitor a sail load, document a peak or feed an alarm strategy. Without a goal, the crew collects a number that is hard to interpret. Note the measuring point, load direction, usual range and the maximum allowed by the installation. Also identify the reading frequency needed: occasional phone check, permanent display at the chart table, or logging for analysis.
The Cyclops Marine catalogue groups sensors, gateways, chargers and cables — but each fitting keeps its own manual.
Smartlink: a removable in-line measurement
A Smartlink inserts into a load path between fittings that match its geometry. The Smartlink² Atto guide calls for a 12 mm carabiner or soft shackle in each opening to reach the stated accuracy, and advises against multiple attachment points in one opening. This architecture suits a portable measurement, or a point where two links can take the sensor without lateral load.
Check the model's working load, the fittings' actual diameter, alignment, and the space needed so nothing bears on the housing. A Smartlink must not be used to hoist a person. A shock, an overload or a deformation may require inspection and recalibration. The documented Atto model measures up to its own WLL; do not transfer that value to another size.
Smarttune: replace the turnbuckle, not add it at random
Smarttune is designed as an instrumented turnbuckle. Size, threads and travel must match the installation. Its replacement modifies a standing-rigging element: unload and secure the stay per the procedure, record a reference length, and have the work done by a competent person.
The French manual specifies that the sensor works in tension through its threaded studs. Pressure on the plastic housing — for instance from an over-tightened furler — can produce an unexpected reading. Orientation, anti-corrosion paste, reassembly and final adjustment are part of the installation. Smarttune makes sense when you want to memorise and reproduce a rig tension; it does not turn a measured value into a universal setting — the target reference depends on the boat, rig, sails and the professional's recommendations.
Smarttoggle: measuring a flying sail
Smarttoggle is designed to be fitted in line between a flying-sail furler and the sail's cable per the manufacturer's arrangement. The manual explicitly states it is not intended for structural locations such as a stay, nor for supporting people working aloft.
Choose the model from the documented maximum working load and pin diameter. Check the assembly stays free, aligned and compatible with the furler. A shock load or overload can damage the instrumentation even if the body looks intact. This measurement helps recover a sail-cable tension or observe loads under way; it does not replace the limits given by the sail, cable and furler manufacturers.
Load pins and Smartbatten: when geometry dictates otherwise
A load pin replaces or instruments a pin designed to carry the load. Its design requires the exact dimensions, bearings, orientation and measuring range; custom versions must be engineered — an approximate diameter proves nothing. Smartbatten measures load on a batten within its range: it answers an aerodynamic and structural question different from a stay or flying-sail tension. Do not lump these products under tonnage alone. When the standard catalogue does not fit the geometry, send a drawing and the loads to Cyclops or the competent professional rather than adding improvised spacers.
Compare load, accuracy and useful resolution
A sensor's manual states a working or calibrated load and an accuracy over that range. A very high-capacity sensor can carry an absolute uncertainty too large for a small load; choosing too tight raises the overload risk. Establish three values: current load, expected maximum and the validated structural limit. Pick a sensor whose range covers the use with a margin defined by the specialist — without making the sensor's WLL the rig's new limit.
After a long period under load, some Cyclops guides note the return to zero can take one to two minutes. An impact or overload may require recalibration. Document the zero, the conditions and the sensor version when comparing sessions.
Plan display and power
The wireless sensors talk to the app and, depending on the product, to a Cyclops gateway toward the boat's marine electronics. Identify the number of sensors, distance, gateway position, output protocol and target display before purchase. Our NMEA 2000 architecture guide frames the network side.
Also check batteries or charging. The Smartlink² Atto uses wireless charging with several endurance modes; Smarttune exists with different battery configurations by size. Watertightness depends on the seal and correct reassembly. A flat battery can produce a missing or misleading value: add that check to the routine.
Official sources
Cyclops Marine — Smartlink² Atto; Smarttune 1/2 inch; Smarttoggle 4.5 t. Manufacturer guides smartlink² Atto issue 2, smarttune issue 9 FR and smarttoggle issue 3, archived and OCRed in the Skysat documentation base on July 22nd, 2026.
