Centreplate Winch

[Ken Leap]

I am building Oughtred's Caledonia Yawl and will employ a steel centerplate, hoisted by a drum winch. I am seeking advice on specifications for the winch, which I intend to construct myself.

The centreplate will weight approximately 180 lbs. I plan on having the hoisting wire go round the axle, with the line on the drum leading aft to a cleat. Here are some of my questions:

(1) What mechanical advantage is appropriate for hoisting this centreplate?

(2) What kind of wire/cable should be used?

(3) How small can the axle diameter be without stressing or distorting the cable in (2)?

(4) Any other comments on this arrangement?

http://www.kenleap.com/images/cy_turning_bow1_lg.jpg
"Reina del Llano"


Ken

http://www.kenleap.com/boat.html

[Jay Greer]

There are many such winches already on the market, both galvanised and bronze. You might try searching on line through this site:
http://www.boat-links.com/boatlink.html
JG

[StevenBauer]

Did you see the one Dale is thinking of for Alistego?

http://www.pfaffgroup.com/pdf/Pfaff%20AW.pdf

Steven

[P.I. Stazzer-Newt]

(1) What mechanical advantage is appropriate for hoisting this centreplate?

Depends how strong you are - I'd guess the V.R. would need to be about 5 to 1, the actual M.A. will depend on the frictional losses - these will be significant.



(2) What kind of wire/cable should be used?

7x19 2.5mm or 3mm should be adequate.



(3) How small can the axle diameter be without stressing or distorting the cable in (2)?

Half the width of the palm of your hand, bigger is better.



(4) Any other comments on this arrangement?

Size the rope part for comfort - 60lb monofil might do the job in theory but it would shred your hands.

[Thorne]

Lovely boat!

Well, with that sort of weight, I'd be *very* tempted to use a commercial-type boat trailer winch, with gears, locking pawl, etc. I've used winches like these on larger swing keels, and like the positive locking element --- plus the ability of weaker crew members to handle the job.

http://shop.easternmarine.com/images/product/4772.jpg

Remember that the centerboard may have a lot more loading than just weight, including seaweed, debris in the slot, or even grounding in mud (which happened to me last weekend and bent the SS pin I use to pin the board fully down).

[JimD]

My winch is just like the one Thorne posted. Not pretty, but only $25 at just about any hardware store and it will provide the advantage to effortlessly raise the CB

[Gary E]

That is a very nice looking boat...much to nice to let this piece of junk pictured below come anywhere near the inside of your boat. It belongs mounted on the trailer to haul the boat up out of the water.

http://shop.easternmarine.com/images/product/4772.jpg

The centerboard can be pulled up with the wire cable as noted above (maybe even bigger) and that is wrapped around a shaft aprox 1 1/4 or 1 1/2 Dia... on the same shaft is a drum 5 or 6 inches in Dia. A rope ...ok...sailboat lingo "line" is wrapped around that to give you the advantage.

Do some math on the setup whan you know where the drum will be and the dimentions and weight etc of the centerboard.

[Charlie Santi]

Ken I in the process of building a centerboard winch for my Wright 'K' sailboat which has a 200lb steel board. Get me your snail mail address and I will send you a copy of the patterns. It is made from a piece of 1 1/2" galv pipe, some wire rope, and some white oak.

[Ken Leap]

Great information everyone--exactly what I needed. The few centerboard winches that I could find online didn't quite fit the bill. I hadn't thought about a trailer winch, but as Gary put it so delicately, it doesn't quite have the look and feel that I am after--good idea though.

I now have better ideas for the size of wire cable, shaft, and drum for the winch that I will build. The shaft diameter was the starting point I needed. With that and the desired mechanical advantage, I can compute the drum diameter. (I'll have to bump the advantage a little for friction, as noted.)

Charlie, my email address is ken.leap@earthlink.net. I'm anxious to see what you have in mind. Snail mail:

Ken Leap
208 Kansas Drive
Portales, NM 88130

Thanks.

Ken

http://www.kenleap.com/boat.html

[JimD]

I hadn't thought about a trailer winch, but as Gary put it so delicately,:D

Mine's out of sight inside the cabin. It's a daysailer/overnight camp cruiser with a very spartan cabin not much more than a cuddy with room for a couple sleeping bags. It does the job wonderfully but I can certainly see why you'd want something a little classier for all to see on your boat.

[Gary E]

I've NEVER been delicate.... no point to it...

[Canoeyawl]

“(I'll have to bump the advantage a little for friction, as noted.)”
While you are doing that figuring you may want to consider a couple of things…
First is that you will only be lifting about ½ the total weight of the board, the other half will be supported by the pin.
Another is that the board when submerged in water will weigh less than in air and will be easier to lift than you may think, in fact the winch may be unnecessary.
The third item is that a steel plate makes a lousy centerboard. There is no foil shape and the weight is not low enough to make any significant improvement in sail carrying ability. Now if you could put those 180 lbs on the rail, it would be helpful!
I don’t mean to be disparaging but these are all lessons that I have learned the “hard way”! LOL

[Gary E]

The Lightning uses a steel plate 1/4 or maybe 3/8 thick and it works well... Worked so well that even when we tried to turn the boat over we couldn't. Even with everyone siting on the low side, and we did have some heavyweights along for the ride too...

But then again I guess it was'nt a "centerBOARD"

[Joe ( Cold Spring on Hudson )]

I would be interested in this for Tidbit it is a real hassle underway to raise or lower the CB and virtually no way to adjust or trim it. Currently it is just a line over a roller with a cleat that is hard to cleat off. But there is no way I want one of the modern looking winches above. :( Is there not a nice bronze or classic style winch? Preferably a side type winch that Steven linked to, so it would great to have that low profile and the crank not rub the trunk.

[Thorne]

Joe, another option to consider is installing a pin that holds the centerboard in one of three positions: fully up, halfway down, fully down.

Drill one hole in one side of the centerboard trunk, go through the centerboard and partially into the opposite side of the CB trunk. Once drilled thru the case, shift the board into the other two positions and drill the centerboard again.

This takes the strain off the pennon/line when trailering or stored on the hard, allows you to pin the board partially up when sailing downwind, or fully down for reaching or if you fear a knockdown and don't want the board to slam back into the case if inverted.

Just watch the pin when near shallow water -- I hit soft ground with the CB pinned down twice a few weekends ago and bent the SS pin (I use an anchor pin) quite nicely.

[Gary E]

I think the pin idea is a bad idea... bend the pin and you could make it very hard to remove... Break the pin and you could make it impossible to remove all the while the board is stuck in that position.

[Bob Smalser]

http://pic20.picturetrail.com/VOL12/1104763/3075025/37657562.jpg

Best design I've seen for a 200lb+ steel plate doesn't require a winch at all.

The various Hartley sailboats have a lever made as part of the plate, and a 3-part block and tackle raises and lowers it faster than any winch.

Note the pin's out in this pic and the board is resting against the back of the case waiting to be picked.

[rbgarr]

Another alternative to get a mech advantage is to have a larger (14-18") reel with a long line on it that turns a smaller drum with the cb pennant. Some Lightnings had those. It may not be very attractive and may get in the way.

[Zane Lewis]

A lot of the trailer yachts here use a worm drive type winch and the other thing is that a spectra/kevlar rope is becoming the norm rather than wire rope. Saves a lot of hassels with rust. You can monitor the condition the same as you would for a wire rope. If it becomes fluffy/(the equivalent of wire rope spragging) it's time to replace it. It's simple to splice over a thimbal.
Even the boad trailer winches are going to kevlar rope or webbing rather than wire here.
I have 8 years experiance useing this agrangment for a 190kg (460lb) dagger board.
With the gearing on the worm drive you can use a 1:1 and it's self locking.
Cheer's Zane

[Ken Leap]

Below is a mockup of my interior and drum winch. I designed a pulley mechanism that allows me to place the drum below and aft of the typical drum location--this keeps it out of the way. Not visible in the pictures is the line wrapped around the drum axel. I haven't decided what materials to use for the drum, but the mockup seems to work pretty well.

http://www.kenleap.com/images/cy_centerboard_winch_lg.jpg

http://www.kenleap.com/images/cy_winch_pulleys_lg.jpg

Ken

[rbgarr]

Ken-

That's the type of arrangement I was referring to above that is used on Lightnings. One caveat is to have a fairlead aft of the big drum which ensures that the drum line stays on the drum. If the line gets slack and unreels itself off the drum's side the drum will spin and the heavy centerbaord will drop uncontrolled. BANG!

Good luck.

[Vincent Serio III]

Try this link:

http://marinestore.co.uk/page/mrst/PROD/davey-rudder-and-tiller-gear/DA3769-GM/

[gert]

http://farm1.static.flickr.com/186/377863580_ec2bbcf2d6.jpg
$707.00 CA:rolleyes: Pass

[JimD]

http://farm1.static.flickr.com/186/377863580_ec2bbcf2d6.jpg
$707.00 CA:rolleyes: Pass

That's what I just paid for a second hand outboard motor. Ya mean I coulda got a winch for my $700 instead? :mad:

[epoxyboy]

http://www.jamesnilsson.com/index.cfm/Other_Products/Centreboard_Winch.html

About 400 NZ$, so a couple of hundred buck to you.