Filippiboats.com
Design and implementation
Rowing boats, spares and parts
Selling rowing boats

The change of the rigger fixing system ( from gunwale to the edge of the boat) brings a variation of stress of the boat. For sweep there is an advantage in particular for the big boats ( 4 and 8) because the rigger rests on both sides of the boat and will be less deformed in comparison with the structure of tubular carbon rigger which instead operates only on one side of the boat. With the scull wing rigger, there isn’t a rib loaded from two lateral forces but it will be the edge (where we’re fixing the rigger) of the boat to be loaded. Moreover the rigger will find its balance since right and left sides are linked, reducing a lot the loads which will be transferred on the boat.
But the structure of the wing rigger, as single entity, shows a minor stiffness than tubular carbon rigger, which guarantees better performances both scull and sweep. Obviously it should be evaluated the “ system” boat.+ rigger to understand if there is a real advantage. May be these considerations are interesting for boatbuilders only. What really counts for rowers it’s the stability of the boat since eventual mistakes can be absorbed by flexibility of the rigger. It would be as you came back from tubular carbon riggers to the aluminium standard version. Moreover since wing rigger is heavier in comparison with carbon and aluminium standard rigger, it’s easier to find your balance during the traditional roll movement of the boat .

Have your say..

What is that small plastic piece on a tip of the blade doing ?

 

The problem of resistance made by oars in the water is old and much discussed . We start from the presupposition that oar must find resistance in the water otherwise it would move instead of the boat and we wouldn’t have the possibility to push forward the boat using the blade as a fulcrum of a second class lever . In reality the oar in order to give back a reaction to the boat must undergo an action by the rower which won’t be transferred immediately in the water. The reaction of the water is simply a compression of the layers of fluid by the surface of the blade. These layers, since liquid isn’t compressible, produce reactions such as to stop the blade . For sure, up, down or on either sides, compressed water can escape. In this escape it will be favourite the external side of the blade because it turns in comparison with his centre of push while boat is going on and water molecules are tending to escape creating a series of slidings on it . Since this thing doesn’t happen in the back side of the blade , the difference of pressure between two sides creates a vortex very intense depending on the push exerted. Because the vortex is a depression , it recalls many more molecules towards itself, autofeeding . These vortices are very resistant (by high energy) if they are very big. Less resistant (lower energy) if they are very small. Plastic part that we insert to the tip of the blade deteriorates the possibility of creating a unique, concentrated vortex, reducing the resistance. Moreover to insert a variation to the ends, an edge, a defect, produces a strong increase of resistance but also a big raising of the vertical forces ( lifting or unlifting, on a base of the wing shape). Above mentioned forces contribute to stop the blade in the water . In motor setting such element is called “Nolder”.

 

What do you think ? Which is your experience about this matter ?