The “Frankenstein boat”-it’s a beautiful monster. Here it is!

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pre-assemblyAtalanta II, the 21-footer that Carlo Puri Negri had built by Bruce Farr in 2004, is like the creature of Dr. Frankenstein, the protagonist of Mary Shelley’s novel. Because it has been remade piece by piece using the best technology. And so it is a monster, but a beautiful monster. (In the original Latin meaning, monstrum in fact stood for miracle, prodigy). Umberto Felci oversaw its refitting, carried out at Maurizio Testuzza’s Adriasail shipyards in Fano, Ancona. Quite a challenge the Milanese designer took on: to make a 12-year-old maxi modern and competitive. A difficult feat, but not an impossible one: the example is that of the 100-foot Australian Wild Oats by the late Bob Oatley, launched in 2003 and continuously modified over time so that it is unbeatable even by the youngest hi-tech behemoths.


ATA old-newNEW AFT PART, NEW LIFE

Felci himself tells us about the new Atalanta II, through the design solutions devised to make it go faster. The first thing that jumps out at us, as we got to see on site, is the new stern: The design, ” explains Felci, “pursued the goal of radically altering the water lines of the last aft third of the existing boat. This was to improve its performance, resulting in a more taut and load-bearing hull shape in the aft part. A shallower and wider stern on the water has as its parametric effect the increase in waterline length, prismatic coefficient (i.e., the ratio of the volume of the hull to the volume of the prism circumscribed to it) and longitudinal inertia, as well as the righting moment between 15° and 25°. These important changes result in improvements on both critical displacement speed and glide speed“. “The increase in righting moment,” the designer continues, “optimizes upwind performance while the increased waterline length and new stern exits improve those at carrying and fast gaits.”

Atalanta 2015 CFR Original hull and keel… AND STABILITY INCREASES
Changes to the hull also result in increased stability:The greater longitudinal inertia achieved by virtue of the new aft volumes, the lower pitching moment related to the new reduced fin draft (from 4 to 3.70 meters, with more concentrated masses)-realized, by refreshing the old bulb, made of CNC-milled cast iron and weighing about 8,350 kg-and adopting new textile rigging, make for better passage over the wave while decreasing pitching. These performance gains will ultimately go a long way toward enhancing the performance/rating ratio in both IRC and ORC“.

ATA stern 2015 - 1
MODIFYING A BOAT WITHOUT INTERVENING IN THE STRUCTURE
As can also be seen from the renderings, the interventions radically changed the shape of Atalanta II’s hull in the aft part, particularly in the last 6 meters.To achieve this, we decided to operate from the outside, making a second partial shell that is Assembled to a structure coupled to the original shell. The exterior finish, involving at least an additional meter of the existing hull, is done with ultra-light stucco and finished with epoxy cycle complete.”

ATA stern 2015 - 2Simply put, keeping the current stern unchanged, a new stern was made “leaning” against the existing one. At the structural level, the new shell should be able to withstand external pressures without bearing other loads, such as those arising from the aft flaps or the rudder lozenge (shaft). The new shell, with a surface area of about 40 square meters, is laminated from female mold and made off-site. The base laminate consists of a sandwich of carbon and PVC with a final thickness of about 30 mm. The part is suitable for a black coloring, so it is made of materials resistant to other temperatures and has been properly post-cured before being assembled to the hull. The four longitudinal panels and the transverse panel were made on a bench, again of carbon sandwich and assembled to the shell with butt bonding. The deck was extended in the aft area in order to join the two shells together, and started with the existing one. The mirror was expanded for the same purpose. The rudder louvre was lengthened until it touched the new shell, while the bushing remained in its original position“.

Atalanta 2015 - new sternAnd again, The paterazzi were moved to the new stern by creating an internal connecting structure that would keep their carrying capacity unchanged. Same for the eyebolts on the freeboard and stern bollards, which were connected to a specially made connecting structure between the two shells“. All this is done so as not to intervene structurally since, essentially, the original craft is not touched or structurally modified.

Atalanta_Sail Plan
In red the new sail plan

UPDATED SAIL PLAN
One of the problems related to the increased wetted surface was more friction and thus a reduction in performance especially at lower speeds: the negative effect, says Felci, “was largely offset by the increase in efficiency and sail plan area. In fact, the latter has been partially modified by introducing a square-top racing mainsail with higher elongation and introducing the use of double backstays, forestay deflectors and checkstay (i.e., paterazzi intervening on the lower part of the tree). To better control shaft deflection. The fractional spinnakers on tangon have been replaced by asymmetric gennakers hinged at the masthead and walled on the new carbon dolphin with a TPS (point of spinnaker tack) 2 meters higher than the old SPL (tangon length). A rollable A0 walled on the dolphin boat will also be introduced. The mainsail has retained approximately the same square footage (about 180 sq. m.) although it has a more elongated geometry (determined by the shorter boom) and the gennaker increases from about 350 to 420 sq. m.“. As for the aforementioned dolphin boat, inside it are housed the pulleys for two gennaker tack points and one tack point for the A0. Maneuvers for adjusting the latter are deferred to the halyard winches in the cockpit.

New interventions in red
New interventions in red

RACER YES, BUT ALSO CRUISER
Lots of upgrades in deck equipment as well. Not only to facilitate maneuvering while racing, but also to make it easier to use the boat while cruising. Felci explains, “Carbon reinforcements and supports were made for the installation of the two winches dedicated to the new double flaps. The coffee grinders and mainsail winch handling were then eliminated (the primary ones were electrified) We then planned to mount a large sprayhood at the main entrance to partially cover the guest cockpit. A flat-drum roller furler was installed in the cruise configuration and remains exposed above the deck. Finally, two mounts were constructed to attach to the columns for mounting twin chartplotters for direct use by the helmsman“.

Atalanta 2015 - crew cabin modification
SMALL (AND FUNCTIONAL) INTERNAL CHANGES

As for the interior, “a new crew bathroom was provided with direct access from the crew cabin, reducing the owner’s shower area. In addition, a removable sleeping platform was made in the forward cabin and a removable bulkhead opening infill, so that an eventual cozy guest cabin could be created but with minimal weight gain“. The main electrical panel was then moved to allow access to the crew shower, and the forward toilet was electrified.(E.R.)


VPP Atalanta CFR PolariTECHNICAL DATA SHEET.

Overall length 21.48 m
Beam max. 4,95 m
Draught 3.70 m
Ballast 8,350 kg
Disl. light about 22 t
Upwind sail sup. 316 sq. m.
Sup. gennaker 420 sqm
Original Farr Yacht Design
Refitting Felci Yachts Design

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