Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[Lance]

I am a novice modeller and am converting a pond yacht (70cm LOA) to RC control. Is it possible to set up an RC drum winch system, with 1 or 2 winches, to control the jib and main sails simultaneously? Can two drum winches be connected to the one RC receiver terminal?

[Leaky Bottom]

Yes, 2 servos or drum winches can be connected to a single receiver output, you will need a Y lead, The plug connects to the receiver and the 2 sockets are for the winch plugs

[Netleyned]

You only need one winch.
Either use a double drum on the sailwinch or a continuous loop with the mainsheet and jibsheet attached at convenient points on it
You would be best puiitng a spring in the line to keep a bit of tension on the loop.
Ned.

[malcolmfrary]

Normally the reason for more than one winch is that there is a need to operate the sails individually, thus on different channels.
Normally a single line from the drum to above deck ending in a block where the lines to the sails connect plus the tension line that ensures that slack lines don't happen.  The tension line can be eliminated by using a continuous loop, as suggested earlier.
A limitation of extra servos on a Y lead is the current drawn. 
Depending on the servos and their loading, this might be more than the wiring between battery and receiver, and through the receiver, can handle.  Most winches are servos, and draw all their power via the receiver. Unless the wiring harness is rearranged to allow for a separate supply.

[roycv]

Hi I have just converted a pond yacht 27 inches long to RC should be featured in Model Boats magazine perhaps next month.
I used one of the Howes of Oxford type multiturn winches which has twin drums in the unit.  A 2 turn winch should do the trick. They are also available on-line from Banggood on the Internet. 
This winch is the same size as a standard RC servo.  These winches do not need a cord set up with elastic returns etc.  They are completely enclosed and the cord comes out as required.  A little tricky to set up but have worked very well for me.
 Use a standard servo for the rudder not a small one as there are a lot of forces at work.  Everything runs from the receiver battery 4.8 volts 2000+mAhr rechargable battery.  If it is a dagger type keel get the RC in compact form so the weight is over the keel.  But if a long keel spread it where you can.

I know that MB magazine arrives a bit late in Oz, but one of the MB contributors also lives where you are.  PM me for information.
regards
Roy
 

[Lance]

Thankyou all for your replies and info. At the moment I am planning to operate the main and jib independently, hence the two winches. I look forward to seeing roycv's yacht in the magazine and yes please location where I can obtain MB magazine in Melbourne would be great.  Cheers

[Netleyned]

If you want to control each sail independently, you will need to use two separate channels.
Using a Y lead will give the same outcome as using one winch.
Ned

[roycv]

Hi LL there is no need for 2 winches as the sails go in and out in parallel, if you have separate channels for each sail then you are making work for yourself each time you tack.
You can make further adjustments by having an ordinary servo with an extension arm to trim the jib a few degrees each way.  At this size the difference is not really noticeable.  I assume you are using a Bermuda rig?
I still go full size sailing but only when I visit Oz and just on my son's yacht.
Regards
Roy

[malcolmfrary]

While the shrouded winches don't need an elastic helper line to stop slack line falling off the drum, the rest of the boat benefits from having one.  Slack line between the shroud and wherever it exits the hull does find things to snag on.  Mostly happens in light airs.  Embarrassing and annoying when the line snags the on-off switch.
The small winches are intended for line about 0.5mm diameter, 80-100lb Dyneema.  When unwinding, you are trying to push a very flexible line out of the hole in the shroud.  If there is nothing to pull it out, like the return end of a continuous loop, or a tension line, it will try to form a lump at the exit point. The hope is that wind pressure will unravel it, but the helper line reduced the chances of it happening in the first place.

[roycv]

Hi Malcolm you are quite right and it is a bit of a trade off for space in the yacht hull etc.  However there is a small thing that helps not a perfect solution but not bad.  If you wind about a 1 inch long length of solder wire into a couple of circles and thread it around the spare sheet coming from the winch it will provide enough weight to pull the line out of the winch drum.  Usually I find it is just the jib that needs it as the movement of the mainsail boom sorts out the other line.  Even a slight wind overcomes the weight of the solder wire.

The other thing is that if the wind is not there you are not going anywhere anyway!
I have all the different systems in use in at least one of my yachts the easiest is the arm winch but you do need a reasonable beam however on two of my yachts I have fitted a very small pulley at the end of the arm and that doubles up the pull length of the line with one end anchored.  Both these yachts have fairly powerful winches so it works well.


I find for small yachts the cheap new type metal gear servos  of about 6 Kgrms/cm pull work very nicely with a 4 or 5 inch arm bolted on.  Sometimes when sailing I wonder if the sails are pulled in or whether the yacht hull is wound in under the sails.

I have a sailing fishing boat which has a minimal keel but is internally ballsted and that sails surprisingly well although does drift sideways a bit when tacking.  It is interesting to watch her travelling as she does not have the slow pitch, pendulum effect of a deep keel.

 I have another sail boat only part made on the back burner, a small Pilot boat with an enormous bowsprit and that is internally ballasted so I look forward to getting that one going.
If things go wrong i.e. too much travel of the lines, the winch with elastic return is the most difficult to sort out.  I sold a yacht to a boater and told him exactly what to do etc and he clearly did not, and brought it back a week later with a total tangle inside.  I had been running that yacht on and off for years with no problems at all!
Regards
Roy



 

[roycv]

Hi Lance I meant to ask, what does your yacht weigh and is that with a mast?  Do you have sails?
Roy

[JerryD]

You only need one winch.
On my yachts they only have one winch. A 6M with a closed loop to keep the tension and a Dragon Force 65 with the same setup.
As a club we race Jiff 65's mine has a single winch with elastic on the deck to keep the light tension needed to prevent snagging.
The two sheets are then adjusted using bowsies from the control line so the slot between the jib and main can be set.
Once you find the right trim for your vessel you'll rarely need to change it, which makes the control simple.


Jerry

[Lance]

Hi Roy, bare boat weighs 3.6kg, requires complete refit - mast, sails, RC gear, etc.

[roycv]

Hi Lance if you send me a PM I can put you in touch with a club more local to you in Melbourne. 

Jusr ckick my name and look to where it says send PM.  Let me know your email address and I will copy you an email from a model boating friend in Melbourne.regardsRoy

[andrewh]

Hi, Lance


Greetings in Locked down and Curfewed Melbourne! 
Happy to help if and when I can!  it it falls outside my experience I can put you in touch with local sailing clubs and retailers


FWIW the Brig in my Avatar has 2 sailwinches on different channels so that I can control the square masts separately


And I had a Thames Barge (Kitty) where I controlled 4 sails from one sail servo.  (NOW I know that I need only have controlled the mainsail)


Photos of what you are restoring?


Andrew
PS, I also speak english

[Lance]

Hi Andrew,
Good to get your email letting me know of a Melbourne enthusiast. Am in the very early stages of project and have many questions especially about winch and arm servo installations and would appreciate seeing an RC installation. Not intending to race, my vessel is a 60yo basic model sloop/cutter format. Looking forward to visiting Melbourne model sailing days after lockdown (?). I live in Williamstown. (Hope the pictures are visible)[size=78%]mailto:57.lance@gmail.com[/size]

[Geoff]

Whilst I tend to agree two sail winches are probably not required for most of our sailing models. I have used two sail drum winches on a "Y" lead what has not been mentioned is that in practice they do not maintain full alignment so you will get differential movement. It may not be too relevant on a yacht but if more accurate alignment is required a "Y" lead doesn't work well.


I speak from experience using "Y" lead for turret turning based on sail winches - they don't move the same amount even if identical models of winch.


Cheers


Geoff

[tonyH]

Whilst I tend to agree two sail winches are probably not required for most of our sailing models. I have used two sail drum winches on a "Y" lead what has not been mentioned is that in practice they do not maintain full alignment so you will get differential movement. It may not be too relevant on a yacht but if more accurate alignment is required a "Y" lead doesn't work well.


I speak from experience using "Y" lead for turret turning based on sail winches - they don't move the same amount even if identical models of winch.Cheers


Geoff

I asked a question in the "Radio Equipment" section about possible end point creep in a small double sail winch where it's connected via Y leads to a couple of micro servos and one of the servos defines the critical end points. Malcolm kindly replied and I think suggested that this was unlikely. In trials I found that a variation seemed to come from the way the line reeled out on one drum and in on the second but the actual end points stayed within a couple of mm so am I just lucky?

[roycv]

Hi re the end point creep if you have the Tx stick on a ratchet it barely notices and like you said it is just a few mms.  There are positions of the Tx stick where it settles though and I figure that any unwanted movement of the winch is unnecessary current being drawn from the battery.
Roy

[tonyH]

Hi Roy,
They're on a switched channel (5) rather than a stick and there are 2 micro servos plus the winch linked by a pair of Y leads. The EPAs for one of the servos is fairly critical >1mm and it's been adjusted so there's zero "buzz".
Tony

[malcolmfrary]

If a drum only gets one layer of line, the travel will be as constant as it can be.  If there is more than one layer, the length will vary by whatever extra diameter the drum gains as a result, and how the line layers settle.
Electronically, unless mother nature alters the circuit (i.e. damp) the information supplied will always result in the same answer at the drum.  What the drum does with the line, and what happens to the line over time is a different question.  Probably why it is a good idea to have a bowsie in the running rigging to take care of that kind of thing.


If handling a loose footed fore like a Genoa, some means is needed to swap sides as well as adjusting for tightness.  That will need another servo, and it will need to be on another channel.

[tonyH]

That's what I assumed from your answer on the other thread Malcolm, so with the net width of the drum being 4mm and 7 turns plus a couple of turns extra, there is almost certainly going to be a second layer on one of the drums except, possibly, around the travel mid point. I was thinking more of the comment from Geoff which, I assume, is down to manufacturing tolerance unless..........
Tony