Drum winch at lowish price

[Colin Helliwell]

I'm trying to choose a drum winch servo for a hull I'm refitting. It's an old boat and design, and my first, so at this stage I don't want to go to the expense of an RMG. The Hitec HS-785HB is obviously very low cost, but how much of a problem is the slow speed - for a beginner, club sailor (albeit keen to do as well as possible!) ?
Are there some options for getting better spec, with just a moderate increase in spending?
(I've had a read of the threads here, but couldn't find a clear answer - and some are old threads referring to obsolete products).
Thanks.

[Hiljoball]

I used an HS785 on my first IOM and it worked ok. Yes, it is slow, so you have to be smooth and anticipate trimming as you round a mark, for example. It is very reliable. Main issues with the slow speed is that you cannot 'snap' gybe and sometimes you can be 'chasing' the trim, moving in and out, trying to find the correct spot, especially on a reach.

Other alternatives include taking a strong servo and modifying it for multiple turns. This has been written up on the UK forum.

Then there are the RMG-like alternatives. I have no info on how these perform and they are not cheap.

John

[Hiljoball]

Additional thought. If you go with the HS785, I suggest mount it on a mounting board, then mount the board in the boat. That way, if you later get an RMG, you can mount the RMG on a board and fit that into the same mount.

John

[Colin Helliwell]

Thanks John,
I'll have a look for the modifying route (or if you can point me to a link or search term...?) - re-engineering summat isn't a problem, so that could certainly be a way forward.
I'd imagine smooth mark rounding is wise anyway, rather than slamming the helm down and sheeting in like a mad thing. (I'm a [full-size] dinghy sailor too - so I'll be the one stood on the bank, leaning 'inboard' in the hope of turning the boat with body weight instead of rudder angle!)

[Hiljoball]

This was not the answer to your question, but the HS815 arm winch works great in an IOM. Similar price to the 785, and faster than the RMG. Add a block to the end of the arm and you can double the sheet travel.

Try search using words like modify servo continuous rotation

John

[Colin Helliwell]

Lol thanks. Space for an arm is a problem though - it's a Nimbus with very limited servo room: less than 4"x3"

[David L Alston]

Colin,
One is always intrigued by the comment ‘ I am a beginner’

Is this beginner intending to bang around the local town pond on a Wednesday/Thursday morning with the old boys, drink team and eat sandwiches?

Or

Is this beginner actually going to race or is racing and hopes to progress?

Why?

Well! clearly because there are two distinctive answers to this so often asked question - is this, or that winch suitable, in this particular case, the Hitec 785.

In the case of the former – a qualified - Yes - it will pull the sails in,
In the case of the latter - a most definite - NO

Beginners and Seasoned skippers alike have more than enough to do when rounding a mark without having to waiting for a winch to sheet in or out or trying to judge when to sheet on the basis that it is going to happen some 3 to 4 seconds later. Besides it is just simply annoying and in days you will hate it.

A beginner can never effective learn how to properly round a mark, how to gybe or most of the essential aspect that claw out that additional few millimetres at each mark.

To me, the Hitec 785 represents the very bottom in winch performance, totally unsuitable for IOM racing in any form, and the RMG represents the highest end of the scale. However in the middle is the AAparts winch - more than fast enough, light, electronically a little week but reliable if you do not sail in gales or continuously for hours on end. Some say these are RMG clones, they defiantly are not, in some respects they present superior value for money, are generally lighter than both the Hitec and the RMG.


There are a number of winches to choose in the range £70 to £100. You are about to spend a lot of time refitting this boat, keep the weight down and a Nimbus is a competitive boat if correctly outfitted, and you will spend about 400 hours sailing it each year, perhaps 2000 sailing over the next five years.

Is your time, effort and enjoyment not worthy of the appropriate choice of winch, or is saving of a few ponds of greater importance. Give yourself a chance, rather make the sails than skim on the winch.



The rudder servo is similar - A slow one is just annoying.

[Colin Helliwell]

Thanks David.
Yes, I'll be racing. I never enjoy pottering/day-sailing in a dinghy and don't expect model yachting to be different - racing is what gives the enjoyment and challenge, for me.
I am cautious about the time I'll be able to find however, hence the wish to be conservative with the initial outlay. As and when I get into it in terms of both time and ability then it would be time to upgrade (probably in full).

Just taken a look at the AA-Parts stuff. A little bit less than an RMG, though not much. Main problem though would be the size - from a quick examination of the hull and plans I'm not sure it can be accommodated. More pondering needed on that front.
Around the 70quid mark would be good, but the choices seem pretty limited - seems there used to be a few more options, but several are now discontinued. The Hitec does sound undesirable though...

[Levend Gurkan]

Colin,

Hitec type slow winches is OK only if you sail alone and never attend a race. I was also using one when I started IOM in 1996 then immediately moved to Whirlwind Atlas which is not available anymore. Replacing Hitec was a huge jump on my boats performance (on trimming and mark rounding)

I can suggest you S300 sail winch from MXComponents. I am using one in my boat and I am happy with it. This is a winch similar to RMG in type and performance. But price wise you can save a lot of money. Also it is compatible with RMG drums so you can use nice RMG drums like self tension one etc.

there are two version of this winch:
S300 is the basic one base price is about €100. This version is not programmable. You should have EPA adjustment on your transmitter (which all new ones has)
S330 is the programmable version of S300. Price is about €130.

have a look mxcomponents.com for details.

Levend Gurkan
TUR13

[Colin Helliwell]

Thanks for the info Levend.
The plastic (?) gears seem a bit of a concern, but as you say - it is at a much lower price than RMG.
I think my next step is to decide whether I dare slice out a big section of aft deck to give me access for this style of winch - currently, I only have space for a Hitec-style drum. If I take the plunge then I'll have room for something larger (and only slightly off from the CoG).

[Dave Pickett]

Colin,

Have a look at the Titan winches, they might just fit the bill. A bit more than your initial budget but cheaper than an RMG and specs look very workable.

http://www.titan-winches.com/tempest/4570036093

[Colin Helliwell]

I've haven't had the time on this project lately, so I can't give 'real' info, but I've purchased a http://www.mxcomponents.com/en/winches- ... 11-ay.html . (Annoyingly the postage was nearly as much as the servo itself, but hey-ho!).
Fits into the existing tray (in fact, is a bit undersize), so easy to retro-fit without a major rework below deck. Runs from 7.2V.
Yet to assess any further...

A further semi-related question, while I'm typing: what's a good cord to use for running rigging? I would guess that Dyneema (which I've used often on 'big' boats) is lower stretch than Dacron? What sort of strength is needed?

[David L Alston]

The only drawback being, apart from the postage cost.. is that it will last about 5 minutes in an IOM at the top of A rig conditions.

And I guess then you will be posting something about how the smell overpowered the swans on the pond.

Don't sail in a 12 kt with A rig and avoid fetching and reaching... this is where the winch works the hardest....

Have fun...see you at Eastbourne Ranking --bring a spare winch.

[Colin Helliwell]

The only drawback being, apart from the postage cost.. is that it will last about 5 minutes in an IOM at the top of A rig conditions.

Oh... what makes you say that?

[David L Alston]

What response did you want or expect ?

… Wow you have got a bargain there my old china plate. We are all going to rush out and fit one of those for sure. Why did we not think it before !!

[Colin Helliwell]

What response did you want or expect ?

… Wow you have got a bargain there my old china plate. We are all going to rush out and fit one of those for sure. Why did we not think it before !!

Well, something a bit more technical, I guess - something about its spec which identifies a reason for possible problems. Or experiences of people who've used it.
(As opposed to more of your offensiveness).

[Dave Pickett]

MX winch spec:

Vigor VSD-11AYMB HV Extra Large 360 Degree/Winch Servo 0.75sec / 50kg / 150g Operating Voltage: 6.0v~7.2v STD Direction: Counter Clockwise / Pulse Traveling 800 to 2200uSec Stall Torque: ≧40 kgf.cm at 6.0V, ≧50 kgf.cm at 7.2V Operating Speed: 0.85 sec/ 60 at no load at 6.0V, 0.75 sec/ 60 at no load at 7.2V Weight: 150g Running Current: 0.40A~0.50A Motor: 3 Pole Heavy Duty Output Angle: 2160 Degrees (6 Circles) Bearing: 2BB Gear: Metal Gear Size: 60.0 x 29.1 x 54.3 mm Lead: 250mm 22AWG, Univeral Plug Special Feature: Water Resistance

Everyone's favourite, RMG280ES

Specification 280ES Unit
Max Output Power 8.6 Watts
No Load Speed 4.1 revs/sec
Stall Torque 15.4 kg.cm
Standard Drum diam 26s mm
Max Revolutions 6 [9.6] 3.2 5 6 Revs
Max Travel (std drum) 610 [975] 320 405 490 mm
Resolution (std drum) 0.6 [1] 0.32 0.41 0.49 mm
Accuracy (std drum) +/- 1 [1.5] +/- 1 +/- 1 +/- 1 mm
Dimensions 85 x 65 x 53 73 x 55 x 50 73 x 56 x 54 73 x 57 x 54 mm
Weight 134 gm

David A, on paper there doesnt look a lot wrong with the MX winch although I have no personal experience, although it seems you have. If you have seen these winches fail in action, please share that experience for the benefit of all on this forum.

Colin, Since you have the winch you will be using it regardless, please take the time to share your experience, it's heavier than the RMG which may indicate solid build........

I have an old RMG winch in my TS2 which works flawlessly, even in weather way beyond top rig when I didnt have my working rig with me, and one is being fitted to my new Shiraz, I have however said before it is expensive - especially as the motor costs less than £1(!) and sailors at my club are looking for something that isnt programmable so that just the transmitter can be used. I would have bought the Titan if the RMG wasn't the recommended choice, as I see it you cant go wrong with the RMG, but thats not to say there are not viable alternatives.

[Barry Fox CAN262]

I'll try to shed a little light. Although the specs sound very similar the two winches are technically quite a bit apart, I think.

I have absolutely no experience with that MX winch but it looks to be based on fairly normal servo technology and the RMG is anything but that. I have used a number of the Hitec drum winch servos at one time or another and I think that, technically, they are similar.

The Hitec works just fine in normal kinds of situations. It pulls the sails in fine in most situations but it is very slow and not too much you can do about it. I see the MX one is rated for 7.4 volts so that might have a good effect on the speed but if you intend to run on a 6V system it will be a bit less stellar, I think.

The other issue is that, as far as I know, systems based on regular servo technology never quit working while they are turned on unless you completely unload the sails. That means they buzz a little most of the time and when that is happening they are drawing current to hold position. And while all that is going on they are heating up some amount. I believe in a really stiff breeze, on long beats, they have the potential (maybe reality) to get very hot to the point of burning up.

And that is where the "smart" part of an RMG kicks in. I don't know how (don't need to know how) it happens exactly but they are designed to kind of lock up when they get to their set position and then hold that without having to constantly feed the motor full power. RMGs are very frugal on battery consumption.

On the other side you have to understand that you can't expect to get the features of an RMG for the cost of a regular servo based part. But if you know the limitations and those are things you can live with for your style/level of competition then you can get sailing and have the fun of sailing your boat. As you progress in skills, and knowledge, you will see the limitations start to affect your ability to improve (probably) and then you can save up for a while and retrofit something like an RMG.

The slower systems actually make you pay very close attention to the conditions around you and require that you do a lot more anticipating as far as sail position is concerned. This can make you a lot more aware of what is going on and then when you can graduate to faster and more accurate technology you will find that you are able to take a bigger advantage of that new performance quicker.

If the budget sail winch gets you on the water sooner and learning about sailing quicker then it has an advantage. Knowing that the performance is not going to be quite as good and that there are conditions to watch out for that could push the less expensive equipment to breaking (and knowing what you have to do to ease the overload on that equipment) allows you to have a reliable sail, get some experience and make changes as you can afford them and they make sense.

Is the MX winch a complete comparable alternative to an RMG? I would say no. But it can work if you understand the possible shortfalls and know you have to deal with them.

You will find that there are those who have a somewhat high and mighty approach to this class. When you encounter them you just have to learn to ignore most of their advice. They are not you, they aren't in your skill/financial/ability position and often have forgotten that we should be here to help newcomers to our class without taking a holier than thou stance.

Get your boat finished, go sailing. From that you will find some good mentors who will be happy to give you good pointers based on your situation. Listen to those folks and ignore the noise.

[David L Alston]

Fellas /

The winch MX #### and one needs to be a little careful here , looks to me very much like the Eurgle. There are/were two versions of the Eurgle both in the same size can one Black anodised and the other Gold Anodised. I bought three of them some years ago for about £19.00 each + PP from the internet. More on that later.

The torque figures refer to a Stall Torque not the Running or rated torque… This is not unusual and most servos are rated/ published in this way. Similarly most manufactures avoid stating what the S1 duty rated torque actually is.

Ok - on to this family of similar or equally type servos in a standard 40x20 package, which may or may not be a rebadged £25.00 Eurgle.

Most, if not all servos of this family, use air core armatures in the motors. This is what gives the servo the terrific sweep time, well it is actually acceleration, but the drawback is that it has no thermal capacity and the temperature rises very quickly.

Even the steel armature suffer the same fate because they are so small but admittedly to a lesser degree.

The heat cannot get out so they die. This is why the 280 Can motor is so popular and used in the top end winches- they are robust and have good thermal characters, plenty of reserve power.

The Stall Torque quoted as 4.0 kgf.cm will in all probability produce nominally 2.0 kg.cm of class S1, USABLE Torque without the temperature rising too high. With a 30mm Diameter drum that result in about 1.4 kg of pull.

See if your winch can lift 1.0 kg on the drum you have.


( I believe there to be a typographical error in the published data on the MX website – never 40 kg.cm. )

The fancy aluminium heat sink does not do very much because the heat path is:-

1/ across the air gap to the magnets and on to the casing and on to the heat sink – not a very good path

2/ or through the motor shaft to the bearing to the case to the heat sink – not very good either.

But it looks really cool.

The next problem is the stalled condition.

The current flows through the FET on one side of the H Bridge to the motor and back to another FET on the other side of the H Bridge.

When the motor is not turning, stalled, it does not generate any back EMF and so the only thing limiting the current is the FET junction voltage drop and the armature winding resistance … The armature resistance is purposefully designed to be as low as possible.

So the current runs away when there is any proportional offset between the actual position and the desired position and the maximum power dissipation of the FETs is exceeded. - conduction loss and switching loss.

The FET junction temperature rises rapidly and ... you guessed it one of the FETs dies a horrid death. Some FETs will go short circuit in these circumstances and take out the other FET in the H Bridge.

Anyway the result is the same …. A charred hole now exists in the circuit board where the device used to be.


This mechanism is made still worse if one runs the servo at higher volts. No there is no over current protection built into the circuit and I hasten to add that neither do many other servos analog type servos.

The buzzing noise is a function of the PWM, pulse with modulation. The PWM is set by the PI controller. The integral action of the controller pumps up to remove the proportional offset error. It buzzes loudly when you pull the string. It stops buzzing when you pull the string too hard and the Mark/Space ratio goes to infinity , no space.

So now you know the mechanism of the demise of a servo that it overloaded or stalled for anything more than a couple of seconds. The result is very smelly, brings sailing to a premature end for that day and is costly

So what does this mean to you, the humble IOM sailor? Well essentially the old adage - You gets what you pay for and sometimes/most of the time even less. There are no free lunches.


You ask about experience…

Well!! I too have dabbled in this morass and when these came on the market some years ago I bought three of them.

The objective being to save weight, I was using the Hitec 5755 arm winch at that time – it weighs a tonne and I was a long way over-weight with the boat.

So .... attracted by the price £19.00 PP I bought three of them.

I went off to the Ranking even at Coalhouse Fort the next week, bang on weight, perhaps a fraction light, I forget the year.

Horror of horrors, the first one died after two heats. Fortunately has spares but I missed heats so back to the bottom fleet. Over the two days they all died one by one. It was top of A rig not yet B rig.

But on the other hand I know of a fellow who uses them with good effect BUT he only races for 10 minutes then takes a break .. hardly ever if never sails in a good 12 kt wind or stronger.

In conclusion –
There is a good reason why the top IOM sailors use the RMG 280.. It works and lasts and lasts. The price might seem ridiculous but there is no other product on the market, in my opinion, to compete with the robust Electronics and Mechanical design. And do not forget that a good portion of the price offset is the Import Duty.

I too look forward to the day when there is a viable alternative to RMG but thus far, in my opinion, there are no contenders to the crown. The Graupner Regatta was a wonderful winch and well priced but they seem to have disappeared - they were made by JR I understand.


I spent £60.00 over two days and had nothing to show afterwards. Was it a bargain ? At that time the RMG was about £110.00.

I know the thought of spending money is horrifying but put it into context... It cost £65.00 to fill my car up with petrol

Listen to Barry, concentrate on ONE boat, finish IT and go sailing. I do not remember where you are but you will be welcome at Leicester. Only a few weeks to Eastbourne IOM Ranking. It is going to blow like hell.

Dave.

[Barry Fox CAN262]

David, a terrific answer.

[Dave Pickett]

Thanks for the responses David an Barry, if more would contribute like this the forum would really come alive! (1183 views, only 19 replies just what is stopping experienced people from sharing their knowledge?)

Only a few weeks to Eastbourne IOM Ranking. It is going to blow like hell.

I will be there but not experienced enough to sail but I am sailing the TS2 tomorrow, just doing a final check on the storm rig!!!!

[David L Alston]

Never worry about experience or the lack of it. The seeding race sort all that out and you will end up sailing with like experienced sailors and will have a lot of fun.

Most importantly however, the experience you will gain will be invaluable and when you get back to your club sailing your club will be well sharp and you will crack some head.

Forums
The problem with this and other forums is that the same old questions keep popping up time after time after time. Most of these questions are better answered at your club where you can see it put to practice and you can practice it. For every question there is a thousand answers ... sorting out the correct answer is the challenge.
But so many want a definitive answer – there is none. It is better to understand the whole
An example - how much do I bend my mast and where ?

Another example - how do some manage to make the HS 5755/56 last - I destroyed 2 in 6 months. Is it because they do not use their winch as I do or am I overly hard on winches ...sheeting in and out quit a lot making small trim changes all the time ... particularly on the reach

Am I running too high or low voltage - 2 cell LiFE .

All I know is that moving away from arm winches saved me £140/ year in operating cost and a lot of acrid smelling smoke.

I sail the infamous 11 or 111. Say hello at Eastbourne. Come to Lincoln on Sunday

Anyway time to get on the plane to come home ...

Dr Dave Alston

[Colin Helliwell]

Fellas /

....

Thanks David. That was the type of reply I was wanting/expecting!

(Annoying that some of it should be down to over-loading FETs - jeez there's so many to choose from, can it be that difficult to pick one up to the job?!)