Trimcontrol relies on eTelltales, electronic pontoons designed to send their position information to a central unit linked to the NMEA network and to the boat's displays (MFD). In the words of Desjoyeaux: to do the Vendée in slippers...

The displays then show a specific screen which shows the position of each telltale and allows to visualize precisely all the telltales mounted on a sail.

Telltales ?

Luff ropes are small strands of fabric or wool attached to the luff of headsails or near the leech of the mainsail. These telltales are double, one strand floating against each side of the sail. 

The attention given to these archaic flow sensors makes it possible to visualize the quality of the airflow on a sail.

A well-tuned sail behaves like a wing, with regular laminar airflow passing on both sides (upper and lower surface).

On the contrary, a poorly trimmed sail still behaves like a wing, but a wing that would stall, to use this aeronautical analogy. In such a situation, the air flows that hit it are no longer laminar, but turbulent.

It is not possible to avoid all turbulence on a wing, but the position of the wingtips is designed to act as a control in areas where, properly trimmed, the wing should not experience turbulence.

Telltales are particularly useful on headsails, which, depending on the material they are made of, rarely allow you to see the leeward telltale, just as their cut and the position of the mainsail sometimes makes it impossible to keep them all in view.

At night, to see a telltale, you have to take out a powerful lamp and the hidden ones at the front are no more visible...

That was before.

The eTelltales!

The eTelltales were developed by Michel Desjoyeaux, who, as he said, wanted to be able to do the Vendée in slippers!

An eTelltale is a small waterproof box of 50 grams including a photovoltaic cell and a small battery and a telltale with a position sensor.

The device can be glued or hooked to the sails and communicates its position wirelessly to a dedicated central unit. Out of service, turbulent or laminar.

Out of order, the sail is not in use or the eTelltale is not working, turbulent, the eTelltale has stalled, (where its woolen ancestor goes up or down), and laminar, the penon is horizontal. 

This information is displayed on the dedicated Trimcontrol app, on Adrena, or on a display -for the moment only Sailmon and NKE support it, but all Navico displays (B&G, Simrad, Lowrance) will follow in 2024-.

What is it for?

Trim Control is for both racing and fast cruising enthusiasts.

If you like to measure yourself against anything that floats like your boat, wherever you are, Trimcontrol is for you. It is a precise and fun optimization tool.

The skipper has a direct vision of the state and angle of his penons, day or night, whether they are in sight or not. He can thus correct his adjustments or his trajectories.

Yes, his trajectories, because the Trim Control is capable of conversing with certain automatic pilots, such as the NKE HR (racing) or the NKE Gyropilot 3 (cruising) from 2024. 

Thus paired, the unit behaves like a super speed controller, with the pilot playing with the helm instructions to maintain the best performance under sail and the best speed (for a given wardrobe and setting).

Offshore racing teams can know precisely the sails used in each navigation sequence to refine their polar definitions and their sail selection (Sailect by Adrena).

The charterers of racing-cruising yachts will be able to know the use of their sails, and note in particular that such or such a charterer has sailed x hours with a genoa whose eTelltales were stalling. Stall of the telltales often means faseyement, so billing for "bad use generating a premature wear" becomes possible.

Pack Alizés = 1452€ TTC (1 receiver with 3 telltales)
Meltem Pack = 1980€ TTC (1 receiver with 5 telltales)
Horn Pack = 2508€ TTC (1 receiver with 7 telltales)
Pack 40ème Rugissants = 4092€ TTC (1 receiver with 13 telltales)

Available very soon at a Breton chain of hardware stores of European dimension...