boardhead

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207 F'n Saint

About boardhead

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    Pennsylvania, US.
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    Travel,Boats and Sailing,Making all manner of stuff go faster, more efficiently.

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  1. boardhead

    Gyrocopter

    So this is MUCH more interesting, a concept that deserves a lot more development offering the stability of an outrageously wide trimaran on the "Atlantic" board and minimal hull drag for light air performance on the Pacific board. I think this looks like a load of fun for a protected waters retirement toy - I could go for this!
  2. boardhead

    Gyrocopter

    Upwind?
  3. boardhead

    Gyrocopter

    When Ryan was looking at options to dock/fix Jzerro I offered my New Jersey facility and it certainly did occur to me that he could have switched rides for his adventure. Just sitting these two, real world, offshore proven vessels side by side and reviewing the fine print in each execution would have been of great interest to both parties.
  4. boardhead

    Gyrocopter

    Trying to stay away from this BUT - Why does a trimaran need to have "a longer ama, with more buoyancy, at least 100%" to match proa stability? An Atlantic proa derives it's stability in exactly the same way as a trimaran - buoyancy to leeward so the the ama design has to deliver all the same requirements. A Pacific proa utilizes the weight of the ama to provide righting moment and light ship that's pretty modest. By adding weight to weather (climbing up the beam/adding water ballast) the righting moment can be increased. When the leeward ama is fully immersed (and doing so causes the rest of the structure to lift into the air) maximum righting moment is reached for that given platforms dimensions. When the windward ama adds ballast (water?) to a point where it's total mass equates to the float of that leeward ama the righting moment is the same so actually the capacities are the same and the reasons for the ama's design differences are more about reserve buoyancy and diagonal stability. Problem is - for the Pacific Proa - you are taking the water for a ride and water is HEAVY! I first sailed on a Pacific Proa over fifty years ago on a brisk day, in big waves, out of Penzance, England with Toy Richardson who subsequently built and circumnavigated in a 45' cat. It was an absolute blast, Toby steering and trimming with me running up and down the aka. We were doing exactly what the Pacfic islanders had perfected so long ago, Cheers (an Atlantic proa) did a fabulous job with Tom Follet sailing her in the '68 OSTAR a few years prior. These are special boats which can be tailor made to satisfy some special needs, I respect that and admire the sailors that have done so but lets be honest, they don't represent some kind of all singing, all dancing breakthrough - rather we are applying known physical properties in a different configuration and if you are just seeking different that's great - ENJOY!
  5. boardhead

    NY to SFO the hard way

    At this juncture the shortcomings of the design and construction of that accommodation/reserve buoyancy wing seem a little cynical given Ryan's predicament, without more information a lot of it is conjecture. I have been out where he is in similar conditions - but in June - it's big boy stuff. The guy obviously is very capable, knows his boat well and is only out there right now because he has the balls to undertake such a lofty endeavor with the resources at his disposal. Fingers crossed Ryan makes it safe to shore and brings Jzerro with him so she get's fixed and lives to wow him again.
  6. boardhead

    Rogue Wave Trimaran

    Sure looks like some quality work!
  7. boardhead

    NY to SFO the hard way

    I used Commanders on several deliveries, they are excellent.
  8. My Saint Francis is currently set up that way, new chainplates are finished but not installed - too cold and wet here right now - will share a picture when they are. In the meantime I will drill and radius a hole in a thick (same as the alloy) slab of quality carbon laminate I have and then slide a length of dyneema back and forth through it. Pretty confident the dyneema will start stranding in no time flat - will report back.
  9. I just use it in the mast where it has been engineered, braided, infused and autoclaved to justify the filaments potential and cost. Could not find anywhere else on the boat where it flies. My new chainplates, which incorporate the spectra lashing eyes, are 6061T6 alloy, cold and dark anodized and titanium bolted to the existing holes where the treacherous stainless steel (iron?) originals dwelt. The beautiful smooth finish in the eyes will let me sleep better avoiding the (small) potential that carbon would have for chafing through the lashings.
  10. Generalizing about “carbon” is confusing. The filament has spectacular tensile strength and when supported in column very good compressive numbers. Higher and lower modulus filaments, the ratio of filament to resin and that resins characteristics all yield different mechanical performance. Zingaro, suffered long term water absorption, degradation, delamination and flex fatigue which pretty much destroyed much of the wooden part of her structure. Dry wood expertly crafted and maintained has produced, what, hundreds on thousands of fine vessels. State of the art carbon fiber structures are so much more expensive and time consuming to build. As Zonker points out lower tech build methods also can have good results but don’t kid yourself you will get 787 wing performance. For myself the overall performance and life of well oriented glass filaments in vinyester resin over foam cores is tough to beat, bang for buck.
  11. Are you talking about filament or matrix fail?
  12. Wood fibers orient in a growing tree to support the overall structure and that structural configuration is dictated by the species dna and the location and surrounding forest. Some grow tall and straight, others twisted and gnarly - appropriate filaments for specific examples refined over millennia - wood is great for making trees. So now we dis-assemble this structure and re-assemble bundles of filaments, selected as best we can from those offered by a diminished supply due to human vandalism, to create our man made structure - it’s a compromise. The stress risers and resultant failures being discussed here are the failure of the designer in recognizing and addressing the eventuality within the mechanical limitations of the selected filament - and that’s OK because there’s a lot to consider and it’s hard. When the selected build material (a bundle of pre-assembled cellulose fibers in the case of wood) makes ideal filament configuration difficult we turn to an alternative (glass, Kevlar, carbon,polyester) to help but there is still much to ponder in the orientation of those filaments and their bond to the underlying structure. Stress relief in a growing tree might be great for that structures development and survival but those filaments performance in their second life with our man made structure is dependent upon our selection and implementation. Starting out with individual filaments of known structural capability gives the engineer a more predictable outcome. Don’t blame the material, blame the designers selection and application.
  13. Not quite sure if that's a typo or not but think you are a bad boy and totally correct!!
  14. Excuse me - I made an observation on the Rapido 50 and that has something to do with me selling and designing boats? I would bet Paul Koch is not enthusiastic about a nice enclosed pilothouse on the back or placing a design premium on three hull contact to reduce heeling and anchorage slamming, The boat was not depicted in the concept illustrations as having high set amas but lifting the windward ama, sailing, reduces drag and in light air some heeling initiates and aids sail set - bolt upright catamarans suffer in drifting conditions. Some feedback on the Rapido 50's unrigged floating lines would be of interest.