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www.sname.org/sname/mt April 2013 vessel is designed using Solid Works Mechanical 3D solid modeling software. America 2.0 includes a number of novel structural features. Cedar/balsa core/cedar composite planking. In order to achieve the lightest planking possible, composite planking was developed and exural strength was con rmed by stress- ing to failure on a four-point test stand. e panel pressure used to calculate extreme ber stress in hull skin planking was 16 psi, which added a conservative factor above the 11 psi required by the ABS Rules for High Speed Craft. Using the strength formula 1 = M/SM, the extreme ber stress cal- culated to be applied to the Port Orford cedar skins of the sandwich hull planking with the required panel loading was 1,190 psi. is compared favorably to the actual modulus of rupture of the Port Orford cedar of 12,700 psi. Testing was performed to ensure that the stresses would be transmitted to the longitudinal wood bers and that there were no weak link shear failures in the sandwich construction that would fail earlier. It was determined that the composite planking o ered the best combination of light weight, sti ness, tough- ness, and insulating properties. Wood planking bond to aluminum framing using potted alum fasteners for redundancy. e planking was adhered to the aluminum anges with epoxy. Preparation for this bond was a solvent (Henkel Parcosol) wipe, sanding, solvent wipe again, and Alodine wipe (Henkel 5700 TDS). A toughened variety of Gurit Spabond epoxy was emplyed for the adhesive in combination with their Ampreg 22 high-per- formance laminating resin. While shear testing of the aluminum to wood face joint epoxy adhesive bond easily surpassed the 1,370 psi shear strength of the Port Orford cedar planking, there was no clear support available for an assumption that such a bond could be depended on for very long-term service (say, 50 years). e most likely eventual bond failure is anticipated to be moisture and corrosion migrating into the aluminum face of the bond. Considering this possible eventuality, a test proce- dure was executed to ensure a su cient mechanical backup for the wood planking to aluminum frame ange connection. Test coupons for Gurit 340 LV epoxy rivets? in a 4-hole test pattern were used to model the actual assembly. Subsequent testing, using aluminum machine screws potted in the same resin, increased shear strength of the con- nection by approx 100% with minimal added expense and so was adopted. is method produced additional shear strength at the interface of approximately 800 lbs. per fas- tener or 6,400 lbs. per foot along girth of frame. Withdrawal strength of potted fasteners was also approximately 800 lbs. per fastener, adding an additional 6,400 lbs. of withdrawal strength per foot along the connection. e withdrawal load was carried about equally by the cedar and balsa using 400 psi shear perpendicular to grain for the cedar and 300 psi for shear to grain for the balsa. Deck bulwark bonded connection to wood hull fram- ing structure. A 2-in. G-10 tube is potted 6 in. deep into the laminated wood hull framing ends with a calculated with- drawal strength (from the frame end) of at least 9,000 lbs. per tube reinforced connection. e high withdrawal strength of the tube is due to the high parallel to grain shear strength of the wood frame laminate. ese tubes, spaced at approxi- mately ve feet, serve to resist moment forces resulting from athwartship pressure on bulwark and vertical tension from rig attachments to bulwark, and also to provide a socket sup- port for removeable lifeline stanchions. Freestanding carbon spars featuring integrated com- posite ttings. Structural spar laminate design was by Gurit High Modulus and executed by Forte Spars. eir directive was to provide adequate sti ness to avoid excessive head- stay sag without shrouds and to avoid whipping fore and aft in a head sea. Meeting these requirements provided a con- servative margin over the mast strength needed to exceed the vessels sail carrying ability. Cutaway rendering of America 2.0s integrated aluminum keel deadwood structure. The America 2.0 structural design was primarily based on a ? rst principles analysis and the ABS Rules for O shore Racing Yachts.