RUBRICA SETTIMANALE “PAROLA DI SKIPPER” | IL CENTRO VELICO

La barca

9.1 Il centro velico

Quando la barca s’inclina per effetto del vento, il centro di carena (CC) si sposta lateralmente verso il lato più immerso, mentre il centro di gravità (CG) rimane dov’era (a meno di barche dotate di ballast, di chiglia basculante o di equipaggio numeroso che in virata si sposta da una parte all’altra). In tal modo le verticali passanti per i due centri si allontanano, ed è per questo che si crea una coppia di forze tendente a riportare la barca dritta.

Il punto in cui la verticale passante per il CC a barca sbandata incontra il piano di simmetria longitudinale è detto metacentro (MC). Perché la barca sia stabile, ossia abbia la tendenza a ritornare dritta quando viene inclinata, occorre che il MC sia al di sopra del CG. L’“altezza metacentrica”, cioè la distanza verticale tra CG e MC, dà un’idea della stabilità della barca di navigare senza fare uso di angoli di barra per contrastare un eccesso di tendenza orziera o, peggio, puggera.

Secondo un’antica teoria, la barca a vela era equilibrata quando continuava ad andare in rotta per un po’ dopo avere lasciato la bara, e ciò era vero per le barche di allora, il cui timone costituiva la naturale prosecuzione della chiglia. Con i timoni staccati e appesi delle moderne imbarcazioni, le cose sono molto cambiate e, lasciando la barra, vi sarà sempre una più o meno accentuata tendenza orziera.

Il CV è il punto dove può immaginarsi applicata la forza generata dal vento sulle vele. Perché la barca sia centrata, il CV va messo in relazione agli altri due centri. Se non vi fosse l’inclinazione, sarebbe sufficiente considerare il solo CD, che è il punto in cui si può immaginare applicata la forza anti scarroccio generata dall’opera viva, ossia dalla carena, con particolare riguardo alle sue appendici.

Occorrerebbe allora che il CV e il CD si trovassero sulla stessa verticale per avere la barca equilibrata. L’inclinazione complica le cose, perché il CV, a barca sbandata, viene a trovarsi sottovento al CR, e ciò genera una coppia di forze rendente a fare orzare l’imbarcazione, in maniera tanto più vistosa quanto maggiore è l’inclinazione.

Più precisamente, le forze della coppia da considerare in questo fenomeno sono la componente utile all’avanzamento della forza generata dal vento e applicata al CV da una parte, e la resistenza all’avanzamento dello scafo, applicata al CR, dall’altra. Il braccio della coppia è la distanza orizzontale e perpendicolare alla chiglia tra i due centri.

Perché la barca resti equilibrata, occorre allora che il CV si venga a trovare a proravia del CD, in modo che la coppia puggera che così si genera vada a contrastare, uguagliandola, la coppia orziera dovuta all’inclinazione. È questo un compito dell’architetto, che lo svolge per le condizioni medie di vento, ma anche dell’equipaggio, che influisce sull’assetto, sulla superficie delle vele e sulle loro regolazioni per adattare la barca alle condizioni del momento.

Tratto dal libro Parola di Skipper, Editrice Incontri Nautici di Giancarlo Basilestabilità

59 Comments

  1. 18/12/2022 at 07:29
    copywriter freelance

    Fantastic web site. A lot of useful info here. I’m sending it to some friends ans also sharing in delicious. And obviously, thanks for your sweat!

    https://www.beatriceverga.it

  2. 19/12/2022 at 06:18
    The Best Places to get Married in Perm (Russia)

    Thanks, I’ve just been searching for information about this subject for a long time and yours is the greatest I’ve discovered so far. However, what in regards to the conclusion? Are you sure in regards to the source?

    https://nftepubs.com/epub-profile.php?symbol=book-39650

  3. 19/12/2022 at 18:54
    The Best Neighbourhoods to live in Shangzhou (China)

    Excellent post. I was checking constantly this blog and I’m impressed! Extremely helpful info specifically the last part 🙂 I care for such info a lot. I was looking for this particular information for a long time. Thank you and good luck.

    https://nftepubs.com/epub-profile.php?symbol=book-34082

  4. 19/12/2022 at 19:21
    The Best Breakfast Places in Bloemfontein (South Africa)

    Hi there! This post couldn’t be written any better! Reading through this post reminds me of my previous room mate! He always kept talking about this. I will forward this article to him. Pretty sure he will have a good read. Thank you for sharing!

    https://nftepubs.com/epub-profile.php?symbol=book-31048

  5. 23/12/2022 at 08:36
    IT Service

    Some genuinely good blog posts on this web site, appreciate it for contribution.

    https://www.c-rown.it

  6. 25/12/2022 at 17:00
    contabilità Online

    Your style is so unique compared to many other people. Thank you for publishing when you have the opportunity,Guess I will just make this bookmarked.2

    https://studiocontabileonline.net/

  7. 25/12/2022 at 22:10
    contabilità Online

    I have learn several excellent stuff here. Certainly value bookmarking for revisiting. I wonder how much attempt you place to create this sort of magnificent informative web site.

    https://studiocontabileonline.net/

  8. 27/12/2022 at 00:37
    https://stone-islandestore.com/

    The following time I learn a weblog, I hope that it doesnt disappoint me as much as this one. I mean, I do know it was my choice to learn, however I really thought youd have something attention-grabbing to say. All I hear is a bunch of whining about something that you can repair for those who werent too busy searching for attention.

    https://stone-islandestore.com/

  9. 27/12/2022 at 16:13
    Beginners Guide to Growing Bowiea (Home & Garden Handbook)

    I think other website proprietors should take this website as an model, very clean and excellent user genial style and design, as well as the content. You’re an expert in this topic!

    https://nftepubs.com/epub-profile.php?symbol=book-2792

  10. 30/12/2022 at 23:24
    Top Places to Holiday in Cartagena (Colombia)

    I will immediately take hold of your rss as I can’t find your email subscription hyperlink or e-newsletter service. Do you have any? Kindly let me know in order that I may subscribe. Thanks.

    https://nftepubs.com/epub-profile.php?symbol=book-62000

  11. 14/01/2023 at 16:00
    She-Hulk cb01

    Howdy just wanted to give you a quick heads up. The words in your post seem to be running off the screen in Internet explorer. I’m not sure if this is a formatting issue or something to do with internet browser compatibility but I thought I’d post to let you know. The style and design look great though! Hope you get the issue resolved soon. Cheers

    https://altadefinizione.foundation/serie/she-hulk-attorney-at-law/

  12. 16/01/2023 at 04:03
    traktor szállítás Europa Road

    I really enjoy studying on this internet site, it has fantastic blog posts. “The secret of eternal youth is arrested development.” by Alice Roosevelt Longworth.

    https://europa-road.eu/hu/traktor-szallitas.php

  13. 01/02/2023 at 10:00
    출장안마

    I just couldn’t go away your website before suggesting that I extremely loved the standard info a person supply on your visitors? Is going to be back ceaselessly in order to investigate cross-check new posts.

    https://misskimanma.com/

  14. 01/02/2023 at 10:25
    출장마사지

    I really like what you guys are usually up too. This type of clever work and exposure! Keep up the amazing works guys I’ve included you guys to blogroll.

    https://misskimanma.com/

  15. 07/02/2023 at 10:22
    crazy time results

    obviously like your web site but you need to take a look at the spelling on quite a few of your posts. Several of them are rife with spelling issues and I in finding it very troublesome to inform the reality on the other hand I will definitely come back again.

    https://city-app.it

  16. 14/02/2023 at 09:17
    Aiuto Tesi di Laurea

    I’ve recently started a blog, the info you offer on this website has helped me greatly. Thank you for all of your time & work. “Cultivation to the mind is as necessary as food to the body.” by Marcus Tullius Cicero.

    https://scritturatesi.it/

  17. 14/02/2023 at 22:20
    crazy time

    You are my intake, I own few web logs and rarely run out from to brand : (.

    https://reteedicole.it

  18. 17/02/2023 at 09:12
    Macedonia del Nord

    Nell’808 il sovrano bulgaro Krum avanzò verso Syar. Durante il regno di Khan Presian (836 – 852), a partire dall’837, la maggior parte dell’area rientrò nei confini del Primo Stato bulgaro fino al Mar Blu. Durante il regno del principe Boris-Michael (852-889) la Bulgaria si convertì al cristianesimo e la Scuola di Letteratura di Ohrid divenne il più importante centro culturale ed educativo, insieme alla capitale, del regno bulgaro.

    https://mazedonische-geschichte.com/it/macedonia-del-nord/

  19. 21/02/2023 at 23:02
    video production milano

    I am constantly invstigating online for ideas that can facilitate me. Thanks!

    https://orbispro.it

  20. 12/03/2023 at 11:21
    quanti kg si possono perdere in un mese

    I do agree with all of the ideas you have presented in your post. They are very convincing and will certainly work. Still, the posts are very short for newbies. Could you please extend them a little from next time? Thanks for the post.

    https://bruciaregrassi.site

  21. 12/03/2023 at 14:10
    bruciare grassi camminando

    Very nice info and straight to the point. I am not sure if this is in fact the best place to ask but do you guys have any thoughts on where to hire some professional writers? Thx 🙂

    https://bruciaregrassi.site

  22. 14/03/2023 at 21:08
    https://superiorpainting.net/

    Hey, I think your blog might be having browser compatibility issues. When I look at your blog in Chrome, it looks fine but when opening in Internet Explorer, it has some overlapping. I just wanted to give you a quick heads up! Other then that, excellent blog!

    https://superiorpainting.net/

  23. 16/03/2023 at 14:48
    folie betonoptik

    Does your website have a contact page? I’m having problems locating it but, I’d like to send you an email. I’ve got some recommendations for your blog you might be interested in hearing. Either way, great blog and I look forward to seeing it develop over time.

    https://www.decofilms.de/folienwelt/folientypen/moebelfolie-in-beton.html

  24. 16/03/2023 at 19:07
    Pools

    I appreciate, lead to I discovered just what I was taking a look for. You have ended my four day long hunt! God Bless you man. Have a nice day. Bye

    https://pool.net/germany-pools.html

  25. 17/03/2023 at 14:47
    Stahlwandpool

    hello!,I like your writing so much! share we communicate more about your post on AOL? I need an expert on this area to solve my problem. Maybe that’s you! Looking forward to see you.

    https://www.mister-pool.de/stahlwandpool/

  26. 18/03/2023 at 02:51
    Come evitare l’usura della biancheria

    Greetings from Idaho! I’m bored to death at work so I decided to browse your website on my iphone during lunch break. I really like the info you provide here and can’t wait to take a look when I get home. I’m shocked at how quick your blog loaded on my mobile .. I’m not even using WIFI, just 3G .. Anyhow, amazing site!

    https://www.shopcentroscampoli.com/blog

  27. 18/03/2023 at 04:05
    Come evitare l’usura della biancheria

    Wonderful blog! I found it while browsing on Yahoo News. Do you have any tips on how to get listed in Yahoo News? I’ve been trying for a while but I never seem to get there! Many thanks

    https://www.shopcentroscampoli.com/blog

  28. 18/03/2023 at 09:09
    Come pulire il forno

    Hey, you used to write great, but the last few posts have been kinda boring?K I miss your tremendous writings. Past few posts are just a little out of track! come on!

    https://www.shopcentroscampoli.com/blog

  29. 18/03/2023 at 10:46
    Come scegliere la biancheria per il bagno

    This design is spectacular! You definitely know how to keep a reader entertained. Between your wit and your videos, I was almost moved to start my own blog (well, almost…HaHa!) Wonderful job. I really loved what you had to say, and more than that, how you presented it. Too cool!

    https://www.shopcentroscampoli.com/blog

  30. 18/03/2023 at 12:58
    Come pulire i divani

    Great – I should certainly pronounce, impressed with your site. I had no trouble navigating through all tabs and related info ended up being truly simple to do to access. I recently found what I hoped for before you know it at all. Quite unusual. Is likely to appreciate it for those who add forums or anything, web site theme . a tones way for your client to communicate. Nice task.

    https://www.shopcentroscampoli.com/blog

  31. 18/03/2023 at 14:39
    Come coordinare la biancheria da letto

    you are really a good webmaster. The web site loading speed is amazing. It seems that you are doing any unique trick. In addition, The contents are masterpiece. you’ve done a fantastic job on this topic!

    https://www.shopcentroscampoli.com/blog

  32. 18/03/2023 at 15:54
    Come pulire la lavatrice

    There are some interesting deadlines in this article but I don’t know if I see all of them middle to heart. There is some validity but I will take maintain opinion till I look into it further. Good article , thanks and we would like extra! Added to FeedBurner as well

    https://www.shopcentroscampoli.com/blog

  33. 18/03/2023 at 17:42
    Come eliminare gli acari dalla casa

    Thank you for another fantastic article. Where else could anybody get that kind of information in such a perfect way of writing? I have a presentation next week, and I am on the look for such information.

    https://www.shopcentroscampoli.com/blog

  34. 18/03/2023 at 19:33
    Come coordinare la biancheria da letto

    I wanted to send you that very little word to help thank you so much the moment again relating to the pleasant tactics you’ve shown here. It has been really shockingly generous of you to deliver publicly what exactly most people could possibly have advertised as an ebook in order to make some dough for their own end, specifically now that you could have done it in the event you wanted. The points also worked to be a easy way to comprehend other people online have the identical desire much like my personal own to learn somewhat more on the subject of this issue. I know there are lots of more pleasant periods up front for those who look over your blog.

    https://www.shopcentroscampoli.com/blog

  35. 18/03/2023 at 21:42
    Prodotti per la pulizia della casa

    Thank you for sharing excellent informations. Your site is so cool. I am impressed by the details that you have on this blog. It reveals how nicely you perceive this subject. Bookmarked this website page, will come back for more articles. You, my friend, ROCK! I found just the information I already searched all over the place and simply couldn’t come across. What an ideal web site.

    https://www.shopcentroscampoli.com/blog

  36. 19/03/2023 at 00:37
    Come pulire le superfici in marmo

    Nice post. I learn something more challenging on different blogs everyday. It will always be stimulating to read content from other writers and practice a little something from their store. I’d prefer to use some with the content on my blog whether you don’t mind. Natually I’ll give you a link on your web blog. Thanks for sharing.

    https://www.shopcentroscampoli.com/blog

  37. 19/03/2023 at 02:55
    Come pulire le superfici in vetro

    I’ve been browsing online more than three hours lately, but I by no means found any attention-grabbing article like yours. It is beautiful price enough for me. In my view, if all site owners and bloggers made excellent content material as you probably did, the internet will probably be a lot more helpful than ever before. “Truth is not determined by majority vote.” by Doug Gwyn.

    https://www.shopcentroscampoli.com/blog

  38. 19/03/2023 at 04:13
    Come scegliere la biancheria per la cucina

    Thank you, I have just been searching for info about this topic for ages and yours is the greatest I’ve discovered till now. But, what about the conclusion? Are you sure about the source?

    https://www.shopcentroscampoli.com/blog

  39. 19/03/2023 at 06:18
    Come scegliere la biancheria in base allo stile di arredamento

    Some really wondrous work on behalf of the owner of this website , absolutely great articles.

    https://www.shopcentroscampoli.com/blog

  40. 19/03/2023 at 07:30
    Come scegliere la biancheria in base alle esigenze personali

    Hi there! I know this is kinda off topic but I was wondering if you knew where I could locate a captcha plugin for my comment form? I’m using the same blog platform as yours and I’m having difficulty finding one? Thanks a lot!

    https://www.shopcentroscampoli.com/blog

  41. 19/03/2023 at 11:18
    Consigli per la pulizia quotidiana della casa

    It’s actually a cool and helpful piece of info. I’m glad that you shared this helpful information with us. Please keep us up to date like this. Thanks for sharing.

    https://www.shopcentroscampoli.com/blog

  42. 19/03/2023 at 13:44
    software gestionale magazzino

    Hi there, simply become aware of your weblog via Google, and found that it’s really informative. I am gonna be careful for brussels. I will be grateful if you continue this in future. A lot of other folks shall be benefited from your writing. Cheers!

    https://gestionemagazzino.info/versioni-precedenti.html

Add Comment

Your email address will not be published. Required fields are marked *