Flat Sails are Okay - mehitabel

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  • 07 Nov 2013 09:54
    Reply # 1429601 on 490687

    I think I built my boat data spreadsheet in the days before broadband, and then it was quite an effort to put it all together.

    In Oscar’s posting dated 03 Nov 2013 11:59 , Reply # 1426821 on 1419786 he mentions a most useful website - http://sailboatdata.com/, which makes my spreadsheet a bit pointless, but this wasn’t available when I needed it but is now an easy to use tool.

    Even so, there are still questions. For example, it gives the SA of the Splinter 21 as 163 ft2 / 15.14 m2 but doesn’t say if that is main and jib, main and genoa or main and 100% fore-triangle. It certainly isn’t 220 sq.ft as given by the van de Stadt office. I would suggest that it is better to use information which is now readily available than my homespun efforts, but even so still question the exact meaning of some of the data.

    Cheers, Slieve.

    Last modified: 11 Nov 2013 16:10 | Anonymous member
  • 03 Nov 2013 17:27
    Reply # 1426928 on 1426810
    Slieve McGalliard wrote:

    Hi Brian,

    It’s interesting that I mentioned the spreadsheet nearly 2 weeks ago and no one else has asked about it. I’m not sure that there would be anything to gain from just publishing it in its present untidy state. If anyone is interested they could contact me off line and we could take it from there.

    Cheers, Slieve.

    Slieve, my point was that if you leave it here and no one takes it on there's a danger it will never get updated. If you post it in the projects forum we'll always know where it is and you never know who will come along. Up to you.
    Last modified: 03 Nov 2013 17:27 | Anonymous member
  • 03 Nov 2013 11:59
    Reply # 1426821 on 1419786
    Anthony Cook wrote:US Sailing has a handy Sail Area / Displacement calculator here

    And here's one using metric units. :)

    Slieve, is there any other information in the spreadsheet besides what you can find on sites like the following?

    Last modified: 03 Nov 2013 12:00 | Anonymous member
  • 03 Nov 2013 10:21
    Reply # 1426810 on 490687

    Hi Brian,

    It’s interesting that I mentioned the spreadsheet nearly 2 weeks ago and no one else has asked about it. I’m not sure that there would be anything to gain from just publishing it in its present untidy state. If anyone is interested they could contact me off line and we could take it from there.

    Cheers, Slieve.

  • 03 Nov 2013 08:35
    Reply # 1426805 on 490687
    Anonymous member (Administrator)

    Stavanger, Sunday

    Hi Karl

    Yes, I too find the top section of my sails very useful, both for strong winds and when sailing into harbour. My sails may have a bit less twist in them now since my new toppinglifts support the yard and top batten. Still, I usually get more twist than on this photo, which was taken in light winds. To avoid unwanted bagginess in strong winds, I devide my sails into 7 panels, as long as the AR is between 1.8 and 2.2, and I aim for equal area in all the panels, or maybe just a bit smaller top panels.






    PS: I am glad to read that your boat is sailing so well. Good rigs deserve good hulls.

  • 03 Nov 2013 04:32
    Reply # 1426768 on 490687
    Hi Arne,

    Yes, you do see camber in mehitabel's sails! Those top two panels are big enough to show the bias stretch. Top Gun is a soft heavy fabric, and just like battens that bend most when we want it least, it billows out most when we'd rather have it flatten. I wrote about this sad state of affairs in an article on the merits of flat-cut sails. 

    But I like camber. I've noticed that when we're reefed to only three or so panels, as often when negotiating an anchorage ready to drop sails and anchor, the twisty fan camber, probably combining with some bagginess, create very usable lift even in fairly light air, and sometimes a bit too much power in gusts. The full sails can point higher, but aren't as much more propelling as their greater area would suggest, if you follow me.

    I prefer full sails for their handling and less chafe, and beauty. If I'd built more than the accidental amount of camber into ours, I think I'd be reefed down a lot more of the time. I'm a timid sailor, really, and don't drive the boat very hard or heel her over very far.

    I do ask the sails to work in a wide range of conditions, though, and I think the flat-cut option remains the best choice for my tranquillity.


  • 02 Nov 2013 17:40
    Reply # 1426567 on 1419736
    Slieve McGalliard wrote:

    I have had a spreadsheet with the data on probably 150 boats for many years, but it has been hacked about a bit and I haven't time to tidy it up. They're mostly boats that are local to the south coast of England, but they do include quite a few 'foreign' boats as well. It is quite interesting to compare boats, so some members may want to play with it. I'm not quite sure what would be the best way to publish it, so if anyone had any suggestions then let me hear them. There are some Bermudan/ junk comparisons in it.

    Cheers,  Slieve

    Slieve, you might want to copy this post onto the new Members' Projects forum where it might find a volunteer. Whether or not it does at this time, it aims to be a good place to log projects so they don't get lost as fora posts wriggle their way into history...
    Last modified: 02 Nov 2013 17:41 | Anonymous member
  • 02 Nov 2013 13:34
    Reply # 1426486 on 490687
    Anonymous member (Administrator)

    Stavanger, Saturday.

    Quite often I have been met with «horses for courses» when I try to «sell» my cambered panel sails. There could be a point in that. When cruising, one is less keen on keeping top speed to windward, offshore, so there may be less need for cambered sails there.



    However, for my use, mainly doing daysailing from A to A, camber simply is a must. This summer I had 21 outings in my little Frøken Sørensen, often in the afternoon or evening, with the wind dying. Thanks to her generous SA/disp (around 22 with two people on board) and her 8% camber, we managed to get home under sail every time. In such conditions, we were faster than Bm-rigged boats of similar size, on all points of sailing. So yes, horses for courses.



    BTW, when looking through the photo album of Mehitabel, it clearly looks to me as if at least the two upper panels have some camber. The top panel seem to have similar camber to what I use in my boats. How come? My hunch is that a good, stiff boltrope around the sail has forced a bit bagginess into the panels.  That could make a significant difference to a dead flat sail, or what do you think Karl?



    Cheers, Arne

    Last modified: 02 Nov 2013 13:36 | Anonymous member (Administrator)
  • 02 Nov 2013 07:45
    Reply # 1426410 on 490687
    Hi Kurt

    Spotted you again today on your sail out of Whangarei Harbour and back in a stiff breeze, where not many other yachts where to be seen and can only confirm that "mehitabel" is sailing remarkably well with her flat sails and a joy to look at.

    Have to catch up soon!

    Rob & Maren

  • 02 Nov 2013 06:18
    Reply # 1426407 on 490687
    Hello Folks,

    Interesting that a quantitative bent has been put on this discussion. I expect that if it were taken to its logical end, flat sails would look less okay than the alternatives on paper, while still being just fine on water.

    I hope most of the readers of this topic have 'gotten it' that the numbers are one thing, and the smile is another.

    mehitabel is just back from an offshore trip and a cruise in New Caledonia. I can't imagine being any happier about the whole affair if I had had camber in my sails to give me x degrees better pointing at 1.y times the speed in wind up to 12 knots. She sailed just fine, numbers or no numbers. We burned 0.0L of fuel.

    A major part of my evangelism, you might call it, for flat sails, has been to promote the junk rig's identification with accessibility and economy. Simple, home-made, magic. Flat sails are okay.


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