How to power a lift keel winch?

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Bobs

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Can anyone help? I have a Dehler 25 with a worm-drive lift keel mechanism. I have recently had an operation which means I'd like to find a way to power the winch as it takes nearly 200 turns to raise or lower! It's a great system apart from the effort - no worries about cables snapping and gravity sending the keel through the bottom!

The winch is on the deck just in front of the mast and uses a standard winch handle with a star-type drive. Question: would a reversible 18v right-angle power drill with a suitable drive fitting be man enough for the job? I don't know how to work out the power requirement but this would be an easy and convenient solution if it works, rather than wire up a permanent motor.

Winding down is quite easy, winding up a little harder so I am guessing I am not producing that much human power but is there a way of calculating the power requirement? A decent drill isn't too cheap so I don't want to waste money trying it out if it's a bad idea from the start.
 
Is there anywhere that you could attach a gas strut to apply some lifting force to counteract the weight of the keel? If you can do that you could make it as easy up as down and reduce the power required.
 
Just a thought but I have seen electric winch handles somewhere for sale. Sounds just the job for what you have in mind plus you could use it on the sheet winches too.
 
Norman_E said:
Is there anywhere that you could attach a gas strut to apply some lifting force to counteract the weight of the keel? If you can do that you could make it as easy up as down and reduce the power required.
Click to expand...

Thanks for the idea but it's all enclosed in the keel box so there's no access to provide any support of the keel. The worm drive takes a lot of the weight of the keel, unlike the suspended strap versions (like I had on my old Jaguar 21) but it does take a lot more turns than the strap type.
 
A good idea Sophie19 but the ones I've seen cost a fortune (like £400 quid plus) so being a skin flint I'm trying to find the cheap alternative of course!
 
I believe windscreen wiper motors develop a lot of torque, if you could rig up a pulley wheel on the keel winch and a drive belt; should be able to get one ( and something with a wheel + rubber drive belt ) from a scrapyard ?

Is your mooring drying or would you be able to leave the keel down at least partly to save some effort ?

I presume there are no suitable deep water moorings or berths handy for a while...
 
I try to keep her on the trailer for the sake of cost otherwise it reduces the point of having a tailer sailer, but I did use a swinging mooring for some of last season. It was more convenient of course but I don't get much time off work so cost per sail is a factor. The windscreen wiper idea is worth a look - thanks for that. Judging by posts re drills in winches it seems you need about 1000 in/lbs of torque so I'll do some investigating. I still like the idea of a drill - so simple to just slot in to the winch and remove when the job's done.
 
Bobs said:
Can anyone help? I have a Dehler 25 with a worm-drive lift keel mechanism. I have recently had an operation which means I'd like to find a way to power the winch as it takes nearly 200 turns to raise or lower! It's a great system apart from the effort - no worries about cables snapping and gravity sending the keel through the bottom!

The winch is on the deck just in front of the mast and uses a standard winch handle with a star-type drive. Question: would a reversible 18v right-angle power drill with a suitable drive fitting be man enough for the job? I don't know how to work out the power requirement but this would be an easy and convenient solution if it works, rather than wire up a permanent motor.

Winding down is quite easy, winding up a little harder so I am guessing I am not producing that much human power but is there a way of calculating the power requirement? A decent drill isn't too cheap so I don't want to waste money trying it out if it's a bad idea from the start.
Click to expand...

Try one of these they have been recommended for this job on another thread and also for electrifying a genoa sheet winch. Cheaper than the marine offerings.

http://www.ebay.com/itm/Milwaukee-cordless-right-angle-drill-/221364194509

Hire shops carry them so try before you buy?
 
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I looked at these; trouble is my keel is on a worm drive, not a simple wire/gravity job so the hoist winch won't work, unless there's a way of turning it 90 degrees and fitting over the top of the keel winch direct (???)
 
A few years ago, a chap in our marina who owned an ETAP 22 with a similar keel worm-drive, used a Dewalt DW960 drill for this purpose. It seems to be MUCH more powerful than the likes of Bosch etc. Anyway, I bought one too, and now use it on numerous jobs on the boat and at home. Also, I've put it to work -with a special bit - to haul the mainsail halyard.
 
Bobs said:
Can anyone help? I have a Dehler 25 with a worm-drive lift keel mechanism.............. is there a way of calculating the power requirement? .
Click to expand...

A little bit of schoolboy physics will work out a theoretical figure, but wont take frictional losses in to account.

Unfortunately several decades have passed since my school days and my physics is consequently rather rusty, but lets have a go.

If you know the weight of the keel, the distance it has to be raised and how quickly you want to lift it then its possible.

The amount of energy , or work, need to raise it, in Joules, is simply the weight (in Newtons) x height raised in metres.

A bit of Googling tells me the keel has a mass of 375 kg. That gives us a schoolboy approximation for a weight of 3750 Newtons. ( we will ignore any buoyancy effects )

My estimate of the height of the lift is about 1 metre ( its not quite vertical, but near enough ) So it will require 3750 x 1 = 3750 joules of work, or energy, to raise it.

Now power is the "rate of doing work" and 1 watt of power is equal to 1 joule per second.

So for the sake of the calculation suppose you want to raise the keel in 250 seconds ( ie about 4 minutes) the power required will be 3750 / 250 = 15 watts.

Stick the actual figures for keel weight, height of lift, and time you want to allow in the above and you will ( I hope) have some idea of the theoretcal power needed. Rather an underestimated figure it has to be admitted because no allowance has been made for friction.


No we will wait for all the flack from the pedants who don't remember one single bit of their school physics but who are now frantically reading pages of Wikipedia :)
 
I believe that a motor/ gearbox assembly intended for mobility scooters would do the trick. They are usually 12v dc so would run off the boat's system. You would need to mount it solidly and probably switch via relays, but electrically it's not a big problem.
I keep threatening to add a similar arrangement to the keel winch on my Anderson 22 as it would save some fuss when singlehanded.
Something like this would be the thing:
http://online.parvalux.com/geared-m...ngle-12v-101w-200w-parvalux-50-771b-p-57.html
Though I would probably look for a mobility scooter spare part from ebay as I am a cheapskate !
The battery drill option could well do it in your case, and if you get a 12v one then a second- hand unit with a duff battery could be plugged into the boat.

Cheers
Rum Run
 
How about using a ratchet box spanner?It would take a long time but give you good leverage.For the drill you need torgue so low revs for a given power
 
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Ref the work calculation
There may be a simpler way. Presumably the OP was not exerting more energy than an Olympic athlete when winding his keel up , ie about 180w, probably much less. Therefore if this additional device is replicating the winding handle not the whole mechanism, that is how much work is being done. Easy!

Cheers
Rum Run
 
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Rum Run said:
Ref the work calculation
There may be a simpler way. Presumably the OP was not exerting more energy than an Olympic athlete when winding his keel up , ie about 180w, probably much less. Therefore if this additional device is replicating the winding handle not the whole mechanism, that is how much work is being done. Easy!

Cheers
Rum Run
Click to expand...

You seem to be confusing work, or energy, with power
 
I was going to say a similar thing I have a Clarke's 240 volt "nut runner" to take of my lorry wheels and I looked at the battery version at the time and it was not a lot of gold and you have a nice tool for tight bolt / flywheel nuts , nuts on shafts ect as well they have plenty of power

http://www.ebay.co.uk/itm/Clarke-CIR220-24V-Cordless-Impact-Wrench-4500635-TRACKED-SHIPPING-OR-COLLECT/151130436666?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D286%26meid%3D4583510232236592327%26pid%3D100005%26prg%3D1048%26rk%3D5%26rkt%3D5%26sd%3D251188822543%26

http://www.ebay.co.uk/itm/Clarke-CIR450-24V-High-Torque-Cordless-Impact-Wrench-FAST-SHIPPING-OR-COLLECT/151202407434?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D286%26meid%3D4583556430740364702%26pid%3D100005%26prg%3D1048%26rk%3D4%26rkt%3D5%26sd%3D151130436666%26
 
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VicS said:
You seem to be confusing work, or energy, with power
Click to expand...

I may be confused, but I do not think I am wrong. One specifies a motor at least in part by defining it's power consumption when running. If the OP exerts 90 Watts to wind his keel, the motor replacing him needs only to do the same, assuming it takes the same time.

Cheers
Rum Rum
 
Thanks for all the helpful ideas - what a great tool this forum is! I think the cordless drill option is worth a try & I'll let you all know if it works! The mobility motor would be a neat solution too if I was confident about my wiring skills.
 
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