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Old Aug 06, 2014, 09:45 AM
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Sailboat size in relation to water area and wind

Anyone check out what is the relation between sailboat to pool or pond. It would seem that smaller area smaller boat. What about light winds ? Does this mean smaller boat? Pond with light wind? Small boat? Large boat? How do you look at this? Thanks Ron
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Old Aug 06, 2014, 11:53 AM
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Boat speed is a factor mostly of waterline length. A larger boat on a smaller pond may be a little tight. As far as the wind goes, a larger boat can handle light winds fine assuming it has sufficient sail area. Conversely, a smaller sailboat will always struggle in higher wind. A small boat in light wind on a smaller pond would be the ticket. Something like the Dragon Force 65 (25 1/2") would be about the limit in a pool in light air.
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Old Aug 06, 2014, 01:07 PM
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Thanks for your input very good. Ron

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Boat speed is a factor mostly of waterline length. A larger boat on a smaller pond may be a little tight. As far as the wind goes, a larger boat can handle light winds fine assuming it has sufficient sail area. Conversely, a smaller sailboat will always struggle in higher wind. A small boat in light wind on a smaller pond would be the ticket. Something like the Dragon Force 65 (25 1/2") would be about the limit in a pool in light air.
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Old Aug 06, 2014, 04:00 PM
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I don't feel size has much to do with it, other than how fast the boat would get from one side to the other. I think it would be more about the boats ability to maneuver.
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Old Aug 06, 2014, 06:10 PM
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Small ponds tend to be shallow so you need shorter keels which tend to be on smaller boats. Big water can mean big waves which larger boats handle better. Wind speed and the ability to cope with it is really more about matching sail area to the wind speed. RG-65 can easily be sailed in 30+ if you put small rigs on them.
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Old Aug 06, 2014, 06:37 PM
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Thanks all. Ever have to swim for your boat on a pond? Ron
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Old Aug 07, 2014, 05:43 AM
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Sail boats can be considered to be scale models of something. As such, the wind and weather effects on the model conform to the square/cube laws of scaling. So a small boat on a large water for what is a pleasant day for a big boat can be something Biblical for a very small one, and a matter of survival rather than sailing. '65s are the ones that cut straight through that. Despite their small size, they just seem to perform better the more wind they get, but the long fin does mean that they need deep water.
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Old Aug 07, 2014, 07:15 AM
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Sail boats can be considered to be scale models of something. As such, the wind and weather effects on the model conform to the square/cube laws of scaling. So a small boat on a large water for what is a pleasant day for a big boat can be something Biblical for a very small one, and a matter of survival rather than sailing. '65s are the ones that cut straight through that. Despite their small size, they just seem to perform better the more wind they get, but the long fin does mean that they need deep water.
Absolutely!
RG65s (and Marbleheads, US1M and to some extent IOMs) do this because of their "ridiculously" long fin and low CG, resulting in high stability. A fifty foot "RG65" would draw 24 feet with a CG about 8 feet below the surface. That is a huge amount of stability.
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Old Aug 07, 2014, 07:27 AM
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I think the Dumas Star 45 and Equation fit that because their keels are deep. Thanks Ron
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Old Aug 07, 2014, 07:33 AM
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I think the Dumas Star 45 and Equation fit that because their keels are deep. Thanks Ron
They both can handle some breeze, but may be a little cramped in a pool.
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Old Aug 07, 2014, 07:43 AM
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I think too big for a pool but it has a long fin. The Equation has the longer of the two. Ron

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They both can handle some breeze, but may be a little cramped in a pool.
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Old Aug 07, 2014, 04:52 PM
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Absolutely!
RG65s (and Marbleheads, US1M and to some extent IOMs) do this because of their "ridiculously" long fin and low CG, resulting in high stability. A fifty foot "RG65" would draw 24 feet with a CG about 8 feet below the surface. That is a huge amount of stability.
From RCSailing, "cludio" explains scaling, hence the reason for long fins and keels on RC boats. Basically direct scaling doesn't work:

http://www.rcsailing.net/forum1/show...y-MODELS/page5


"Scaling up or down :

- Linear dimensions are following directly the scale factor.
- Surface dimensions are following the square of the scale factor
- Volume dimensions go with the cube of the scale factor"
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Old Aug 07, 2014, 05:04 PM
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Or from Skene's Elements of Yacht Design. Stability goes with the 4th power.
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Last edited by Gregg28; Aug 07, 2014 at 05:57 PM.
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Old Aug 21, 2014, 02:33 PM
heyharv
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HI all, I am new to this site.

In regards to size and handling ability in different sailing area, yes the smaller boat will be more comfortable in smaller ponds however in regards to wind conditions on average the smaller boat performs quite well against larger boats. When the winds are very strong the heavier boat performs better. Claudio has right it is very hard to produce a scale sailboat that will sail ok. Our sailing club in Montreal often races 55Ē boat at 20 lbs with 1meter boats at 11 and 8 lbs and with a handicap start makes it interesting sailing.

I have developed a 1 Meter Dragon re drawn from the original Anker lines however modified for RC by trying to keep the look of the boat as scaled as possible. Considerations to keel depth, sail area and hull weight become crucial however it can be done and the results are quite impressive.

This dragon weight in at 8.2 lbs complete RTF and sails great even in heavy airs. It responds faster then the heavy boat and I am not a 100% sure but I think it points higher. The waters we sail are weedy and boats like IOM AC100 or any fin boat really does not sail very well in these waters. I think that boats under 1 meter are more fun in light air then heavy airs.

I will post a few pics and a video to show the performance of a smaller boat unfortunately I donít have them with me I am at work lololo.
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Last edited by heyharv; Aug 22, 2014 at 09:34 AM.
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