PROFURL - sail reefing systems for boats (headsail, mainsail)

The PROFURL in-boom reefing/furling system is designed to be used with long battens allowing the same performance as a fully battened mainsail with a normal or increased roach: the mainsail performs even better than a normal mainsail because the gap between the mast and the sail is a direct application of the "slot effect" commonly used in aerodynamic applications.
	The PROFURL in-boom system allows for : fully battened mainsail, maximum roach, outstanding mainsail efficiency.		In-mast furling : battenless mainsail, smaller sail area, extremely flat mainsail.

The slot effect (patented)

Extensive tunnel tests carried out by PROFURL at the Centre of Research for Architecture and Nautical Industry (CRAIN) have clearly shown the advantage of creating a gap between the mainsail and the mast, to create a slot effect commonly used in the aeronautical field: when aircraft prepare for landing they open a foil at the front end of the wings to increase the lift and avoid airflow detachment.

The PROFURL in-boom system is a direct application of this feature.

With the luff profiles located behind the mast the airflow is literally sucked into the gap between the mast and the sail with a sudden acceleration, which dramatically reduces the area of the sail affected by turbulence.

The "working" area of the sail and the power are increased by 5 to 15%. On the other hand the "slot effect" makes the airflow more stable in spite of minor wind or course changes, making the power of the mainsail more constant.

Weight optimisation

The different structural components of the PROFURL in-boom system have been developed using the method of finished element theory calculation. This process is extensively used in the aircraft industry and allows for the best weight/resistance ratio for the system.

Less windage of the furled sail when boat is in harbour

With the PROFURL in-boom system the mainsail is completely furled inside the boom profile. When in harbour the mainsail looks more unobtrusive than with a conventional mainsail where slugs or batten cars remain stacked above each other.
When completely furled the mainsail can be protected from weather with a simple mainsail cover, which is easy to fit and to store in the boat when not used.

A large size diameter tube pointing downwards and located near the forward end of the boom profile allows for quick draining of water and rainwater catching.

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