hey Paul Jensen-need your e-mail address to send feedback on the fin you sent me.The foil is definitely from the George Greenough/Paul Gross school of thought.You guys are going to make a believer out of me yet.PG has been telling me for years the virtues of thicker, round leading edges,especially for the hulls he builds,so I have slowly been going in that direction-3/8"-1/2" and now what I assume to be 3/4".To me upon first inspection they just look like they wouldn’t work-too much drag etc.however, I am learning that,at least for the hulls I ride, they DO work and work great!They allow the hull to get up and running and find the sweet spot on the wave-they maintain their speed through turns,etc. Matt
hey Paul Jensen-need your e-mail address to send feedback on the fin you > sent me.The foil is definitely from the George Greenough/Paul Gross school > of thought.You guys are going to make a believer out of me yet.PG has been > telling me for years the virtues of thicker, round leading > edges,especially for the hulls he builds,so I have slowly been going in > that direction-3/8"-1/2" and now what I assume to be > 3/4".To me upon first inspection they just look like they wouldn’t > work-too much drag etc.however, I am learning that,at least for the hulls > I ride, they DO work and work great!They allow the hull to get up and > running and find the sweet spot on the wave-they maintain their speed > through turns,etc. Matt …And compared to a flex fin??? Paul Jensen
…And compared to a flex fin???>>> >>> Paul Jensen to be honest, I would like to have a fin like the one you sent me,only made out of volan and flex it out a bit to really compare/contrast.I’ll see if I can get that done.
to be honest, I would like to have a fin like the one you sent me,only > made out of volan and flex it out a bit to really compare/contrast.I’ll > see if I can get that done. …One potential drawback of a solid glass fin with a similar template and foil might be the weight of the fin…
…One potential drawback of a solid glass fin with a similar template and > foil might be the weight of the fin… For the fin
s core in the lower 2/3 or so, you can use a 10 or 15 lb. density polyurethane foam, hand pour or pre-formed sheets. Much lighter, the core floats and will allow a good measure of thickness vs. tuned flex. Plus, a foam core of that density wont easily point load, fatigue, and form stress “hinges”… much superior to the lower density surfboard foam commonly used inside the rails of flexible surfcraft. Dale
For the fin
s core in the lower 2/3 or so, you can use a 10 or 15 lb. > density polyurethane foam, hand pour or pre-formed sheets. Much lighter, > the core floats and will allow a good measure of thickness vs. tuned flex. > Plus, a foam core of that density wont easily point load, fatigue, and > form stress “hinges”… much superior to the lower density > surfboard foam commonly used inside the rails of flexible surfcraft. How about using wood for the lower half of the fin and just have flex in the tip? pros/cons? regards, Håvard
How about using wood for the lower half of the fin and just have flex in > the tip? pros/cons?>>> regards,>>> Håvard Håvard, Yes, you could do that, but high density foam allows the freedom to subtly taper the structure downward toward the base with much less weight. For fin designers, the issues of increased foil thickness vs. weight vs. structural flex of high density PU foam allows a wider range of performance than wood. In addition, aside from the issue of moisture, architectural PU foam is far more consistent in density, strength and texture than wood. The option of being able to hand pour the PU foam is also a tremendous advantage over the limitations of solid wood slabs. Dale