1/10 Scale frigate...

[rwatson]

Both - a trailer/sailer, capable of 20 knots under outboard power.

http://schoolroad.weebly.com/project-2.html

[BATAAN]

Here's one I built, and some others I rigged.
If you want a sailing model, about 1/6 scale is about right. The 100 gun ship in the green screen shot is 1/12th scale, the brig whose deck I'm standing on is 1/4 scale and the BLACK PEARL the modelmaker is in front of is 1/6.

[GAZZABO]

In Russell NZ there is a 1:5 scale model of Cooks Endeavour built by Ralf Sewell and it sailed! It is in the museum there and has photos and I think a film of it sailing.

[vhhjr]

I am impressed Mr. Bataan! Did any of these models sail? What a fun job.

This is a hypothetical question as I have never built anything like these ships. Only some models. There is a company that makes large scale sailing ship models:
http://modelsailingships.com/ships/grasshopper.html
Using their Brig as an example, it is 50" on deck, with an 18" beam and weighs about 72 lbs ballasted. The sails are radio controlled using 4 winch servos. If this was scaled by 5X for a 21' length and a beam of 7.5' and it's scale weight would be 9000 lbs. A 4X version would be about 17' on deck with a 6' beam and a weight of 4600 lbs. I assume the high weights are to balance the scale sail rigs. The ballast might not have to be this high as I have scaled the ballast as a cubic function and sail area scales to the 2nd power. Using this approach the gross weights would be 2700 lbs for the 4X and 4900 lbs for the 5X. This would cause the hulls to float higher in the water than scale.

How reasonable is it to assume that the saling data from the model would be applicable to the scaled up versions?

Would it be possible to control the sails using the same bracing system that these models use?

VHH

[rwatson]

Sounds like you are on the right track vhhjr.

Just bear in mind, that the wind force is also cubed (like ballast) - so scaled ballast on a model may need to be higher to cope with the "cyclonic" 10 knot breeze encountered by models on the local pond.

That's why model yachts have to have such big lead bulbs and long keels.

I would love to see a radio controlled square rigger - it must be possible. Getting it to look authentic would be worth it.