Want to try something really new? With the Bow, now in its third year, we are pursuing a completely new concept in sailmaking and the interaction between sail and mast. The Bow's unique ability to adapt dynamically over a huge wind range while continuously developing the same amount of drive has excited many windsurfers.

Windsurf Sail Program Windsurf Sail Character

> 4-Cam Concept Sail for Freerace, Slalom and Foil
> 2 offset clew claws for trim flexibility and easy use of a trim system
> No Loose Leech, the Bow uses more surface
> Special friction bearing that allows rotation of the mast
> 3D Mast Sleeve Shape and Cross Batten Concept
> Neoprene Cover at boom opening for better aerodynamics
> Tack Strap to regulate the tension of the sail foot
> Bow Flex mast is mandatory

Here you find the mandatory BOW Mast.

With the new Bow Flex 2.0 mast generation, this dynamic has been further improved. Thanks to its versatility, the sail is ideal for foil, freerace or slalom. With its deep profile with 4 cams, the sail develops a rich performance and accelerates effortlessly to an exhilarating top speed. Thanks to the special geometry of the sail, as well as the ability of the mast to rotate inside the boom, the profile continuously adapts and the sail always remains easy to control.

In its third year, we made further updates, focusing on the evolution of the Bow Flex mast. The sail construction features additional Kevlar reinforcements to precisely control the stretch of the material and save weight. Instead of outhaul eyelets, the Bow is equipped with Clew Claws, which facilitates the use of a trim system. The success of the Bow continues. Experience the Bow concept and be part of the innovation.



Cam Top IMCS Best Mast** Mast
6.9 205/198 493 7/7 4 fix ./. Bow Flex 70% 490 699,- 599,-
7.8 224/216 504 7/7 4 fix ./. Bow Flex 70% 490 709,- 609,-
8.7 237/230 519 7/7 4 fix ./. Bow Flex 70% 490 729,- 629,-

* Upper eyelet / Lower eyelet
** The Bow Flex Mast is mandatory for the Bow sail. The special Friction Bearing is also supplied with the mast.



With the BOW sail the GUNSAILS R&D team introduces a completely new concept in sail design.
Within 2 years of continuous development, Pieter Bijl and Renato Morlotti have managed to realize this innovative idea in a sail. The BOW offers new dimensions in handling and wind range and shows a unique efficiency. With its adaptive capabilities, the BOW delivers constant power and effortless drive across a huge wind range.
The sail is not only perfect for foiling, but also provides a new feeling of windsurfing on a freerace or slalom board. This innovative concept also includes the specially developed BOW FLEX mast, which is rotating within the sail.


The BOW concept is based on a new sail outline with an extreme bending curve in the top. This extreme curve is only achievable with the BOW FLEX mast.
Due to the low luff tension and the innovative design, the sail does not have any loose leech. In the following the functionality of the BOW concept is explained in further detail.



Thanks to a special friction bearing, which allows the mast to rotate within the boom, the mast can rotate inside the sail, thus allowing the upper area of the sail to twist and bend away.
In contrast to the Loose Leech concept, where only a small part of the leech twists, the BOW has a much larger area to adapt to the strength of the wind.
When the wind strength and thus the wind load in the sail increases (high loading), the upper part of the sail turns leeward and the profile adapts dynamically.
The holding forces on the boom remain the same. Only the profile adapts to the higher loading.
When the wind force and thus the load in the sail decreases (low loading), the sail turns back to its original position. Now, the lower wind energy is compensated by the more efficient profile.
The drive as well as the holding forces remain the same. This ability facilitates handling enormously and also improves performance while going upwind.
The described adjustment of the BOW is more dynamic and effective than the Loose Leech mechanism. Due to the well defined and firm edge at the leech, there is no fluttering and the associated small stalls in the profile.
Similar to a Loose Leech sail, the BOW regulates itself in gusts and wind holes, but the available area is larger and more efficient. Thus, it covers a much larger wind range in total.
For the windsurfer, this ability leads to an effortless and comfortable windsurfing experience, combined with the performance and drive of a camber sail.
Due to its continuous drive and feather-light handling, the BOW sail is predestined for foiling.



The ground of any sail design is based on a tension triangle that is created between the clew, top and mast. This is also the area which can be actively controlled by the windsurfer at the boom. The special outline of the BOW sail allows it to have a bigger area within the tension triangle. The now bigger area of the sail that can be directly controlled by the windsurfer, does lead to a significant increase in efficiency and control. A BOW sail can therefore be chosen in a smaller size compared to a Loose Leech sail.


Current sail concepts have the ability to adapt to a certain degree to the prevailing wind force. The area that allows the load to be redirected from the sail is called the release area. Marked in blue here. The adaptation of the BOW sail, caused by the rotating
and very flexible mast, enlarges the release area considerably and lets it extend far into the sail profile. In the marked area, the profile changes depending on the wind force. It is precisely this relatively larger area that makes the unique adaptability of the sail possible. However, most of the release area remains within the Tension Triangle. That means, although the profile adjusts continuously, it retains its efficiency and can be easily controlled by the windsurfer.






GUNSAILS | Testbericht Bow 2019 Surf Magazin

THE IDEA: GunSails developer Pieter Bijl explains the concept as follows: "Conventional sail design is all about combining good light wind power with control in strong winds. For maximum power, you need a tight leech that doesn't twist or waste energy. For top control, however, the leech must turn away and let off pressure, so we used to need the loose leech. So in the end you went round in circles as a designer, it was all about balancing the different requirements - power and control - and making compromises. With the Bow we want to throw the constraints of conventional sail design overboard. The leech should be stretched to avoid wasting energy. Due to the very soft mast at the top, the top should tilt downwind in strong winds and prevent the sail from becoming top heavy. In one trim, the Bow can cover a much larger wind range than conventional concepts."

So much for theory. Here are our impressions:

ON THE BEACH: The mast is one of the core elements of the new concept. All three Bow sizes work on the same 490 mast length - the 6.9 only extends a few centimeters, the 8.7 just under 25 centimeters. On the outside, the Bow mast looks like any normal SDM mast. But if you press the mast into the sand with your top, you immediately notice how soft and flexible it is in the upper part. For rigging, the mast is pushed into the wide mast pocket above the camber, as is usual with most camber sails. The best way to push the mast through to the end is due to the strong pre-bending of the mast sleeve in accordion style. Even without luff tension, the Bow now has almost as much mast bending as normal freeracing sails in fully trimmed condition. The folding of the four cambers is also quite simple, if you know the decisive trick: Put the luff halfway through and press the clamps directly from the front of the mast sleeve - you should start with the camber above the boom. Only then is the luff pushed through. In view of the low trim forces, one seriously wonders whether one is really rigging a 4-cam sail at the moment. With a small trim aid, such as the trapeze hook, a halfway strong surfer can easily pull the bow through, the otherwise necessary trim cranks for racing sails can be completely dispensed with. You first have to get used to the fact that the bow is designed without loose leech, so apart from some small wrinkles in the top area, the leech always stays tight. Before the boom is fixed to the mast, a thin mast sleeve made of hard plastic has to be put on, which should allow the mast to turn in the boom head piece. The boom is also only loosely attached to the boom, as known from freerace or race sails. With prices between 669 and 699 Euros, the Bow is in the lower price segment for freerace or race sails - direct sales make it possible.

ON THE WATER: The Bow has a deep profile and is very stable in the hand. In the lower wind range the sail already develops a lot of basic draft, who pumps on, notices in fact that in the top range of the sail nothing does itself: No fluttering, no rustling, the Bow loads up with light wind well. In full glide, the sail feels balanced in your hands and remains drivable for a long time even with little tension on the outhaul. Whether the mast actually rotates within the mast cuff, as the designer intended, cannot be checked during the ride - and ultimately doesn't matter. What is certain is that we had no problems with the boom slipping, it sits just as tightly on the mast as usual. We were positively surprised by the camber rotation in particular: On sails with a very deep profile, sometimes the crucial point, the profile of the bow changes sides without any problems, all four cambers rotate completely. In terms of weight, we think the Bow is within the normal range for this sailing category.

SURF-CONCLUSION: The Bow really has what it takes to be a revolution. Just the fact that you can pull a 4-cam sail almost without any trim is remarkable. In our opinion, the goal of the developers to develop a concept that covers a large wind range in one trim has been achieved. Despite its user-friendliness, the Bow remains a sail that is primarily recommended for sporty windsurfers who are looking for a powerful motor for freerace and slalom boards and who don't have any problems with far out foot strap setups and water starts.

A small drawback: You can't avoid the special mast (399 Euro) under any circumstances. During our test on Sylt the wind conditions changed a lot - from gliding conditions to full speed runs everything was there.