It LOOKs very nice. I remain extremely sceptical.
Please correct me if I am wrong, but I estimate off the top of my head that the displacement is in the order of 150 g. The batteries alone will take up around 100 g. of this.
EDIT LATER. Having done the sum on a calculator instead of in my head, the target displacement comes out at 46 grammes, assuming tha the full-size boat weighs 10 tonnes. This is the weight of 2 of the model’s four batteries. The whole project is totally impractical.
i did not scale down the ocd 60, i carved a shape out of balsa that is styled after the ocd 60. to guesstimate the displacement of a shape you’ve never seen before, based on the shape of something that differs to that shape, is pretty damed ignorant. that’s some ego you have. any who, your wind sounds like that of an naval architect, that is why i would like your valued advice on the shape i’ve carved. i would like to get some of these done, so i have something to muck about with at the pond this spring. my plan is to make five prototypes, and send them out to people with experience, to help me out. you definately sound like you know your stuff, that is why you’ll get one. that’s about enough yappin fer me,got molds to make. i’ll let you’se know when some are done.
Looks light to me too, Nigel … try this …
Weigh her … draw your intended waterline on the hull … stick her in the water … considering she’s carved from balsa your model isn’t going to weigh more than a fully ballasted, rigged boat … then again, hell maybe it is …
… I’m guessing you’ll find her transom dragging a hole through the pond … could be wrong … in fact, I’d rather be wrong … she is a sexy looking thing … on the other hand, should Angus be right, you will have saved yourself a lot of work and for certain egg on your face …
regards and best of luck, Trevor
ps …
other option of course … I already offered you a complete set of hydrostatics … all you’ve got to do is trace her profile, stations at midships and stern, and plan … and post the file … you’ll have a close enough answer with 24 hours …
i’ll do that this weekend, and get some stuff uploaded.
What Open 60 are you involved with … ?
Considering the above I don’t think it is too extreme of Angus to assume that your hull is fairly close to scale, what would be the point of a mantel display model otherwise. From there he simply did the calculation and came to a conclusion based on what you had said. Therefore I do not think that he deserved to be spoken to like that. We have a pretty friendly forum here and ‘no personal attacks’ is part of the signup agreement. Worth thinking about next time please.
Graham
Graham puts it so nicely.
If I built a 240 tonne Open 60 and said it was ‘inspired by a Footy’, would you laugh?
nigel, would you happen to be named derick hattfield? the guy sailing “spirit of canada”? i was only 7 at the time, but i think you talked to my dad about purchasing a Quest 30 modeled after a boat called “Hotglue gun”?
i’ll get the drawing made soon.
the 60 i helped build was derick hatfield’s OCD 60 “the spirit of canada”.
i’m sorry for the sour mouth.
i would laugh at the 60’ footy, (only because normally, i’m pretty cheerful).
no i’m not derick hatfield , i’m nigel.
rudder mold is semi done. test lay-up resulted in a 3.5gram proto. still mucking about.
more rudder pics
another rudder pic.
and another one
That looks like a nice piece of work Nigel, nice blade shape…
Graham
Let us examine this weight of 3.5 g.
We have no dimensions, but let us assume a restangular rudder with a span of 100 mm, a chord of 38 mm and a thickness ratio of 7%.
This gives an area of 38 cm2 and a block volume of 2.66 cm3. Assume further that the block coefficient of the aerofoil section used is 2/3. The volume of the rudder is therefore 1.77 cm3 and its maximum thickness is 0.266 cm.
If we make this out of ultra-HIGH density balsa (320 kg/m3), the weight of the bare balsa blade is 0.567 g. We will need to coat this with epoxide. Assume penetration of 0.133 cm (i.e. half the maximum thickness) on each side, that the volume penetrated is totally taken up by resin (a very unfavourable set of assumptions) and a resin density of 1.96 g/cm3. This gives a total weight of resin of 1.94 g, and hence a total weight for the complete rudder of 2.50 g.
In other words, a conventional epoxide saturated balsa rudder is some 30 percent lighter than Nigel’s carbon one. Once again, there is no point in using high tensile materials in a Footy unless they can be used in very small quantities. Beautiful as his craftsmanship is, the exercise is pointless.
I wouldn’t call it pointless. As stated, it’s a first run. If you want to continue to see other builder’s attempts, success and not-so-much, we need to be a bit more encouraging. 30% sounds like lots of excess weight until you realize that’s it’s one gram. A consistant shape may be more valuable than the weight of a raisin.
Angus, with the greatest respect, some times you talk a load :censored: xxx, xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.
Nigels rudder looks to me to be a superb piece of workmanship, something I would be proud to own. IMHO its weight is not important. What is important is that firstly he has built it and secondly that he has shared it with us.
I would suggest that there is more concern given to so much that does not matter with these little yachts where as actually building and sailing them is far more worthwhile.:devil3:
So, my message to all is, stop twittering on and go sailing.:zbeer:
i agree with angus. this first one, out the mould, is a very resin rich, test piece. some scrap cloth lying around was used, and some old wst system sauce. lighter, higher quality ones will soon follow.
for the people who believe it is a fine piece of craftsmanship, don’t be fooled by “web photos”. (not like there fake or nuthin) when i am happy with some final results, i will make a bunch up, and send them out to whom-ever wants some stuff, so they can judge the craftsmanship, firsthand.
i’m not a yapper, my work speaks for me.
hot wind is hot wind, good work is good work.
p.s. that first one is now a key chain.