Wind speed, sail area, ballast and heeling

I sailed the Prince in 10-15 mph winds last weekend with gusts up to 20-25. She heeled over to the point of having the guns in the water and water pouring out of the ports. Got my attention a couple of times! [:-snorkel]

I had asked a question about the relationship of these things to each other and how close the 1/24 model is to the full scale ship in response and heeling qualities. Here is an interesting explanation I recieved from the maker of the kit.


I don’t suppose the roll response is particularly similar, but
neither is the relative wind force and its variation or the
righting moment.

I am sure you realize that the scale of 1:24 is lineal (as in
the length
of the ship), but the area scale is squared 1:576 (as in the
area of
sail ) and the force/mass/volume scale is cubed 1:13,824 (as in
weight of the ship). The wind being always at 1:1 (so,
relatively, 24
times faster on the model than in real life), has a force is
acting on a
sail area that is 1/576th of the real ship’s. The wind force on
sails causes the ship to roll, counter-acted by the ballast
(which if
it’s location was a direct copy) would give only 1/13,824th of
righting moment of the real ship. It all makes comparisons a

So the ballast keel is a compromise to try and make her sail
well (and
realistically) at reasonable wind speeds without making her too
draughted or too stiff.

The Prince has the lightest displacement of our ships and is
over-canvassed (as she was considered in real life) to give her
speed. These two factors forced the deepening of the ballast
keel and
the associated stiffness.



Now math was my worst subject and I’m not sure I follow all the stuff Philip stated but it seems to me that it would be a compromise to get the roll response. Either it is rolling slow but more (heeling further), with the ballast where it is; or rolling less and reacting faster, with the ballast placed lower. I don’t think I want a “more stiff” response. So my options are limited. I will need to use less canvas in the higher winds or get ready for a heart attack when it lays the sails in the water. The model does come with a “reefed” version of the driver and that is what it is for. As you can see in my pics, I sailed with the full driver and the main top gaff sail as well. It is great for the light wind but not the conditions it was used in last week.

Does this also mean that a 10 mph wind is really 240 mph at my models scale? I find it hard to believe, but If it is so…it is amazing to me that she even sails as well as she does.

Anyway…I just thought it was interesting stuff.


Always choose the lesser of the two weevils!