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[ianb]

I've just completed my first R/C yacht. I followed the kit instructions for sail control, a winch with an endless loop system for controlling the sheets. Seems to work OK, when the ice melts on the pond I'll find out.

Obviously there are other ways to control the sheets - separate winches with elastic tensioners, sail arms with or without pulley multipliers and so on.

Somewhere I read that the response is different depending on which system is utilised. Question - what are the differences in response, and what are the other pros and cons of the various systems in use? Is there any ideal system, or is it just personal preference?

Still learning very slowly,

Ian

[tigertiger]

Sail arms are faster. They go through the whole range of motion in under a second. This suits some smaller boats. However if the boat is very small across the beam you will not be able to use a long enough sail arm to operate/control/pull enough length of sheet to do the job.

The longer the sail arm, the more length of sheet you can pull. However, you need to balance the torque (kg/cm) against the cm of the arm.

A sail 'drum winch' can have up to 6 turns (depends on actual model), the speed of turn is a factor, but the torque is less of an issue. Very expensive sail winch drums are fast, cheaper ones are not.

Another consideration. Sail arms are largely tangle proof. Drum winches can cause problems if the line goes slack and hops off the drum. You need to look at a tensioner mechanism.
Continuous loops are another solution, and require a drum winch.

There is no simple answer.

I prefer sail arms, and use 1/4 scale servos where I can. But 1/4 scale servos are large and would not fit well in smaller boats. My preference is based on speed and that they do not tangle. Also 1/4 scale servos are cheap and powerful, but would not fit in my smaller boats.

This  is my personal preference.

Many sailors prefer sail drum winches, but the can be much more expensive.


I would tend to go with what  is recommended in your plan/kit. If for no other reason, the geometry has been sorted out already.

[warrior193]

I've just completed my first R/C yacht. I followed the kit instructions for sail control, a winch with an endless loop system for controlling the sheets. Seems to work OK, when the ice melts on the pond I'll find out.

Obviously there are other ways to control the sheets - separate winches with elastic tensioners, sail arms with or without pulley multipliers and so on.

Somewhere I read that the response is different depending on which system is utilised. Question - what are the differences in response, and what are the other pros and cons of the various systems in use? Is there any ideal system, or is it just personal preference?

Still learning very slowly,

Ian

Hi Ian, my Windstar IOM has drum and this seems to work fine for me - as tigertiger says sail arms are much faster but current thinking seems to be that they can be too fast if you are not expert at sailing these  small yachts - the tendency being to "fiddle" with the sheets too much (which then spills the wind from the sails) this tendency is probably much greater when learning. Part of the problem is that it is difficult to see when you are getting it wrong with the sheets as you are so far from the boat, very high sheet speeds will tend to make this worse. My Nova Scotia gaff schooner has sail arm sheets and I have managed to destroy two servos on this. I think that a winch gives you more "feel" , but there is a bit of a weight penalty with them. As tigertiger says, there are some very fast, light sail winches out there - but the price will make your eyes water - more for the Marblehead guys or the IOM champs
Regards, Brendon (warrior193)

[tony23]

if your tending to use your yacht for racing you need a winch that will sheet in quick around a marker (or buoy) so so you want a winch that's fast if you have the space go for a drum winch but as the guys say a good one is not cheap a Futaba or Graupner is very good and worth the money I use an RMG winch  http://www.smartwinchuk.co.uk/ but I race IOM's so this one could be over kill for you. Forget Eurgle winches from HongKong there cheap for one reason there very slow and and you'll need a computer radio to set the end points.
If you have the room go for a Hitec arm winch you will not go wrong with one.

[Jimmy James]

There are two other ways of handling sheets but they are used mostly on the older type of scale boats
 1) capstain --- Vertical  -- a geared motor 50/1 or 100/1 mounted with the spindle comming up through the deck and a capstain drum fitted on with a grub screw
    I use these for hauling the yards on square riggers it keeps the rigging on deck so its easy to repair or adjust and it doesn't look out of place as most square riggers had    1,  2, or even 3 or 4 on deck  the control is with two micro switches or a home made Bobs board used as a 3 way switch
     Capstain (Drum end) ---Horizontal-- Same as above but mounted horizontally through a Deck house, Foc'le or Poop Bulkhead

 2) Counter weights --- These run up and down in plastic or metal tubes and are attached to the hauling (end) part of the sheets and are set up so that if t gust hits the vessel the weight of the wind will lift the weights and allow the sheets to slack out and so help prevent a knock down--- This is a very old way of controlling sheets and is rarely used these days
Freebooter 

[ianb]

Thank you all for your most informative responses.

I'm using a Futaba S5801 winch which does 2 rotations (360's) in 1 second, making it about as fast as a sail arm servo. Two revs. corresponds to full sheet in to full sheet out in my case.

I note that warrior193 said that he destroyed two sail arm servos on his gaff schooner and I'm glad that the Futaba has metal gears. One less worry! In Model Boats a few years ago a build article reported that the two Hitec sail arm servos used on a Metcalf "Monica" did not work out at all and had to be replaced with more powerful units. I guess that there are a lot of heavy, unbalanced stresses on a sail arm servo.

Thanks to your information and advice I now feel that the winch and winch system should work well for me. If it doesn't, I'll be back asking for help to solve any problem! The weather is getting better every day and I'm looking forward to getting out there by the end of the month and really sailing.

Cheers
Ian

[ianb]

Sorry, my bad.

The servos used in the Model Boats build article "Monica" were Supertec, not Hitec as I mistakenly wrote..

Getting old...........

Ian