EXCLUSIVE VIDEO Here’s how the U-mast works without a boom!

We had been waiting for this moment with great curiosity: we wanted to understand if the system developed by Daniele Mingucci’s start-up Stramba, namely the boomless inverted “U” mast (we had presented it to you here), really worked or if it was the usual “boutade.” So we sent our own Bacci Del Buono to Padenghe del Garda (Brescia) to see the system up close. Here’s his report from the Zuanelli Shipyard, where the first boat in history (the 47-foot aluminum “Futura”) is being built, with the rig designed by Mingucci.

THE GENESIS OF THE U-TREE
“Coming back from a boat ride, I realized I have a really bad back. True, I am tall but let’s face it, the bomb in the middle of the boat takes away space and is really uncomfortable! So I asked myself — how can I take it off!!!?” So, in 2011, Stramba start-up CEO Daniele Mingucci began to conceive of this strange rig: an inverted “U” mast, without a boom, on which the mainsail runs from one tack to the other. Daniele Mingucci and his entourage, day after day, are creatively finding more and more optimized and functional solutions by facing with much humility and determination the various technical obstacles that gradually arise.

VIDEO – THE “TURN” WITH THE INVERTED U-SHAFT

HOW THE WEAVE WORKS
The tree, or rather the two “legs” of the aluminum tree are made up of four trunks, two on each side, measuring 9 meters each. At the top of these the two mastheads are joined together by an inverted “U” on which the mainsail slides from one side of the mast to the other. The bearing sector of the tree is 18 meters high, while the height including the “U” is about one meter higher. The two “legs” are joined by two structural sleepers. The first is at the height of the joint of the two sections, the second is at the height of the “U” joint.

The latter is very interesting since it is also the base of the rail on which the jib forestay attachment runs. By doing so, the jib can “follow” the mainsail from one tack of the boat to the other, bringing closer the idea of “creating a sail plan that has maximum continuity between headsail and headsail, maximizing the potential of this boat’s yield and performance.” This rigging conformation, of course, does not include any rigging. Very similar to what we know as structural steering wheels, there are two patarazzi anchored to the mast at the height of the stringers.

leggi anche

These seven accessories are perfect for relaxing on a boat this summer

LA RANDA
The mainsail looks more like a kite sail inferred vertically on the mast with Harken rails and trolleys. It is symmetrical in fact and has a double square top. The lack of a boom, at first glance, worries and not a little, but the Stramba team reassures, “For leech tension we are testing a very simple system inspired by the Optimist peak that can tension tack and leech with the halyard.”

THE VIRATE.
This is how the turn takes place: the maneuver may seem complicated and cumbersome at first, but engineers are working to make it simple and manageable even on a solo basis. In fact, the mainsail must be run by means of the part of the halyard that is upwind along the entire length of the “U” of the mast. What used to be the halyard, finished the maneuver will be used as a cunningham and vice versa. In the prototype boat, named Futura, all maneuvering will be handled by electric winches conveniently controlled from the cockpit. It should be mentioned that the halyard runs outside the shaft in the “U” part with the help of small tapered pulleys.

THE KILLING
And now we come to the abatement: the biggest problems to date are on the abatement (which for a project with the name “Stramba” is rather paradoxical). In fact, assuming that the boat is in the stern at the moment the mainsail slides on our inverted “U” there is a possibility that it will catch wind “slipping” between the two masts like a spinnaker risking breaking the battens. The other eventuality is that it does not deflect at the time of the maneuver by bulging over the rail. As of now, tubes have been arranged (on the U) that follow the profile of the sail passage to prevent this from happening but we have been assured even safer, more effective and aesthetically elegant solutions are under consideration.

THE ADJUSTMENT.
“As for the adjustment in gait, we chose a solution inspired by ancient Chinese junks.” For upwind, the trim that engineers are aiming for is one that sees a continuity of airflow between the headsail and mainsail. Therefore, no overlapping of the genoa on the mainsail is planned, but rather an attempt will be made to have a trim such that the result will be one large sail.

TERZAROLS.
The reefers: about how to take hands and handle a tack with a reduced mainsail, The Stramba team does not yet want to comment officially. “There is a very simple solution that we will optimize in the coming months (but we can reassure everyone: we won’t be spinning a bunch of rolled up sail).”

THEHULL AND THE DESIGN
Now nearing completion is the welded and pre-assembled aluminum hull from the Mor shipyard in Castegnato, Brescia, which is about to arrive at Zuanelli’s for finishing. The prototype, Futura, is a 47-foot (14.32 m), 2.40 m draft, 4.60 m beam boat, built to a completely original design by the Department of Industrial Engineering of the University of Bologna (Prof. Ing. Alfredo Liverani) for structures and water lines, and by Q-id for design. Armo, interiors, and structures were optimized by the Stramba team led by Eng. Massimo Tamburini and Filippo Rossi and strong collaborations with Eng. Stefano Signori, by young designer Saverio Panichi and Giuseppe Dimilta, FIV Level III instructor. A far from minor role also falls to the “support team” led by Mario Zuanelli. Also important was the advice, for the tree, of “guru” Franco “Ciccio” Manzoli.

leggi anche

Guido Bernardinelli, “How We Won (Again) the World H-Boat”

The interesting part is that no struts or structural bulkheads will be present within the. The ribs and their stringers are welded together to ensure the structural soundness of the whole boat and the rigging. This gave designers (Q-id) the opportunity to reinvent below-deck arrangements. Definitely out of the box are the lines of the deckhouse and deck space arrangement.

The cockpit is tiny with only one rudder: all the habitability of the hull shifts to the bow. Indeed, the designers were able and willing to make the most of the ample space left by the lack of a mast piède. The result is a boat with a deck that approximates the comfort and design of a modern and somewhat futuristic motor unit. About performance, studies conducted in collaboration with the University of Bologna are having truly amazing results. For now, it is a performance increase through 30% better lift management. but for this we could be more precise only once we touch it with our own hands-or rather helmed with wind.

THE WEIRDO TEAM
The Stramba team is working to build and fine-tune a performance prototype featuring the new patented sail boom. Up for grabs is the opportunity to experience new and extraordinary on-board spaces, but more importantly, the chance to achieve higher performance in gait. A third research front is the simplification of maneuvers and adjustments. http://www.stramba.it/

DISCOVER ALL TECH, ACCESSORIES & PRACTICE NEWS