tow line winch

[sammykParticipant @sammyk]

hi all fellow modellers I would like to put a working winch on the rear deck of my tug boat.my idea is to use a sail winch to control the tow line ,my question to all is will the sail winch be strong enough or will it strip the gears out the servo.I intend to use a metal geared servo on 6 volts.regards sammyk

[sammykParticipant @sammyk]

[Dodgy Geezer 1Participant @dodgygeezer1]

As far as I know, all sail winches come with a 'stall-torque' figure, which is the maximum pull they can exert. You decide how much pull you want, and then buy an appropriate winch.

I believe that full-size practice involves using the winch to pull a defined load, then locking it and doing the tow with the line secured to a hard-point. This would be because towing might involve the line slackening and then snatching, possibly putting a very high momentary force on the line, and you don't want to damage the winch…

[Dave MilbournParticipant @davemilbourn48782]

I don't know how much line you anticipate winding in and out, but the winches I've seen have a maximum number of around 6 turns, although this can be extended by inserting something like an ACTion P96 in the connection.

Ideally you want a small motor running a worm and pinion drive arrangement, perhaps with limit switches at each end of the travel. It could be driven from a proportional channel with a twin relay switch like the ACTion P44. See the top diagram here **LINK**

DM

[Malcolm FraryParticipant @malcolmfrary95515]

The winches that Dave mentions have a drum diameter of about 1", so a 6 turn one would give about 19" of travel, depending on the transmitter.

Yes, use a servo with metal gears, but run it on 4.8 volts. Worked hard on 6 volts there is the possibility of letting the magic smoke out (I have the t-shirt with badge on that). To make room for the multi turn gearbox inside the case, the electroncs card is minute. That can be replaced with one of those cheap 10A ESCs from China via ebay when you get as many turns as you like having lost the use of the position sensing pot. The only limit there is how much line you can get into the shrouded drum. With any winch there is the problem of avoiding slack line tying itself into an immovable tangle.

[sammykParticipant @sammyk]

thanks for your help lads ,the six turn winch will do fine ,the main problem i have is when the tug is close to the barge the line goes slack and sinks then when i move the tug the prop gobbles up the line.so the idea was to spool the line in as the barge comes close then unwind when as tow starts .so my next question is when the winch is fully paid out is there any strain on the servo .regards sammyk

[Malcolm FraryParticipant @malcolmfrary95515]

In theory, yes. In practice you will probably move the boat that the winch is fixed to first. To reduce the chance of tangling it might be a good idea to have a loose running weight on the line. If it causes the line to sink it both helps keep it away from the prop and hopefully stops the chance of the line tangling in the shroud. Thats another theory.

[Dodgy Geezer 1Participant @dodgygeezer1]

…the main problem i have is when the tug is close to the barge the line goes slack and sinks then when i move the tug the prop gobbles up the line…

If the only problem is taking up the slack, then you don't need a powered winch at all. You just need a sprung winch drum – a bit like a roller blind. And you can do that easily with a rubber band or a small spring. The winch drum will have a fixed stop at, say, 18", and have a weak sprung rewind to pull slack in.

A sprung drum will spool the line in far more rapidly and accurately than a radio-controlled winch. And it's lighter and cheaper…

[sammykParticipant @sammyk]

thanks for all your help lads,as all ways the getting of wisdom is never easy .i think i will mock something up with the sprung drum idea and have the winch as a plan b.regards sammyk

[sammykParticipant @sammyk]

update to the winch .after some mock ups i went with the sail winch on its side on the rear deck of the tug boat which is connected to the winch drum.,when the line is fully out the load is through the winch mountings so no strain on the servo.in use when docking the boat the line is winched in to the required length .to move out the winch is not moved till the tow is under way which means the line is always tight .this was tried out at the club today and it worked well but it was bitter cold so the trials was cut short till warmer weather comes along .regards sammyk

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