CD03 - Issue #74: Designer / Builder Paul Bieker--Process Control ...

Early in his professional career, PaulBieker worked on the design,construction, and repair of ships andcommercial vessels, such as theF/V Starbound, a Bering Sea boat.often to "address stress concentrationsso cracks wouldn't propagate until youcould haul the boat to do a proper fix.The solution was to cut structure awayrather than reinforce it. An old-timeronce told me, 'Stiffness attracts load.'There are situations you get into wherethe more stiffness you throw at it, themore load it's going to take. That's theparadox of modern design. You can getaway with a lot more in a plywood boatthan a carbon-fiber one."Take the early 14s, for example," hecontinues. "They were designed for thematerials at hand, which meant a lot offraming and thin planking. There's agreat deal to be said for that type ofsingle-skin panel, which can move a bitand not fail, because flexing washes outthose high instantaneous pressures.That's one unfortunate thing, in myopinion, about the America's Cup structuralrule: big penalties basically make itonerous to go to single skins. I think itwould be a more interesting designproblem if they said, 'Thou shalt havean average panel weight greater than x,'and let you do it however you want."Bieker remains committed to the lightweight of cored panels, though, andthinks that failures are more the resultof inadequate engineering than inherentflaws with materials. "In a lot of boats,the internal structure is not very wellthought out," he says. "Also, I think ABS[American Bureau of Shipping] rules foryachts give just a little too much creditfor large panels. The rules allow you tosignificantly reduce your design pressuresas panels get bigger. They presumethat smaller panels are more likelyto experience large pressure spikes.Still, when the boat slams, the pressureThe sail plan and underwater profile ofa Rip Tide 44, Bieker's newest design.He's a firm believer in lightweight, fast,but readily manageable sailing yachts.76 PROFESSIONAL BOATBUILDER