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Old Jun 02, 2014, 09:44 PM
3d pilot
United States, GA, Fort Oglethorpe
Joined Jul 2010
28 Posts
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Skip Jack sailboat help

I am building the skipjack a 5 foot tall and 5 foot long sailboat and I don't know what servo to use for the sail wench can any one please help me this picture is not one of my boat its one I copied on line but it is the same boat I am building
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Last edited by elijahjue; Jun 02, 2014 at 10:28 PM.
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Old Jun 02, 2014, 09:54 PM
Registered User
Monterey Bay California
Joined Feb 2004
13,984 Posts
How much does she weigh and how much sail area does she have?

Also, is the ballast internal (centerboard only) or do you have a non-scale keel/bulb as well?
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Old Jun 02, 2014, 10:00 PM
3d pilot
United States, GA, Fort Oglethorpe
Joined Jul 2010
28 Posts
Quote:
Originally Posted by Aerominded View Post
How much does she weigh and how much sail area does she have?

Also, is the ballast internal (centerboard only) or do you have a non-scale keel/bulb as well?
the boat is about 22lb's the mail sail is 46" from the top of the main mast to the bottom and 43" from the main mast to the end of the boom and 55" were the battens are not sure what you mean about the ballast this is my first sail boat sorry
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Old Jun 02, 2014, 10:08 PM
3d pilot
United States, GA, Fort Oglethorpe
Joined Jul 2010
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I think when you say non-scale keel/bulb you talking about the led wait if so I have a 10lb led that bolts to the bottom of the boat
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Old Jun 02, 2014, 10:47 PM
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Monterey Bay California
Joined Feb 2004
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Yes, re: keel, non scale would be external ballast, a bulb, on a fin. yours bolts directly to the scale keel? what would you do with the centerboard?

I'm not really familiar with the skipjacks that are sailed by the vintage group of the AMYA but do they have non scale bulb fins?

...using your main sail dimensions and eyeballing your jib, I'd guess you have somewhere around 1400 square inches of sail.

with the 10# of ballast bolted to the bottom of the hull, you might not have much righting moment. a removable fin/bulb may be better.

...that question decided/defined, you will have a better idea of the kind of torque you will need for your wench.

My guess is that your boat might see the same sheet loads as an EC12, or Santa Barbara, roughly, if the keel isn't particularly deep. but...

Sorry to be circular in my reply... Still some unknowns.
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Old Jun 02, 2014, 10:58 PM
3d pilot
United States, GA, Fort Oglethorpe
Joined Jul 2010
28 Posts
the led keel wait is 5 inches tall from the bottom of the boat to the end of the led wait and it is 11, 1/2 inches from front to back if that helps
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Old Jun 03, 2014, 12:17 AM
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Monterey Bay California
Joined Feb 2004
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Are you working from a set of plans or did you design this yourself? Model Skipjacks are pretty popular in the Mid-Atlantic.

I wonder what those guys are using for wenches?

Again, as a guess, I'm thinking something comparable to what EC12's and S/B's use. the larger RMG wenches or perhaps something from Servo City. One challenge you face is also the need to move a lot of string since your main has such a long boom.
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Old Jun 03, 2014, 06:32 AM
Brighto?
Mike Denest's Avatar
United States, DE, Newark
Joined Dec 2003
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Quote:
Originally Posted by Aerominded View Post

I wonder what those guys are using for wenches?
When I owned a Catalina 34, I tried to put as many wenches on the boat as possible. Unfortunately getting them to properly set up a winch for the next tack was a problem.

I'm sorry, I couldn't let that one go by.
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Old Jun 03, 2014, 06:37 AM
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Australia, TAS, Penguin
Joined Mar 2012
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Thinking that some sort of RMG winch would be the go in a boat this size....? They are expensive but would do the job I would think. There are a range of winches to choose from.
https://www.rmgsailwinch.com.au/

The RMG sailwinch is Australian; there is also an alternative made in Europe somewhere I think.
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Old Jun 03, 2014, 06:47 AM
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United States, DE, Newark
Joined Dec 2003
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Try one of these: http://www.servocity.com/html/top_mo...l#.U421mhDbAeg
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Old Jun 03, 2014, 12:39 PM
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Monterey Bay California
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Originally Posted by Mike Denest View Post
I'm sorry, I couldn't let that one go by.
Yeah, l know...

Hopefully elijahjue now has some ideas about they may need for winches...
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Old Jun 03, 2014, 05:43 PM
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United States, KS, Wichita
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Very nice looking boat!
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Old Jun 03, 2014, 06:03 PM
groundlooped
sydney nsw australia
Joined Mar 2005
297 Posts
google us vintage yacht group, they have a section for vintage schooners and skipjacks etc.
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Old Jun 03, 2014, 07:32 PM
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Canada, BC, Maple Ridge
Joined Jul 2011
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There are a couple of challenges to overcome. One is how much power, second is how many turns on a drum, and third is the difference in boom length between main and jib and the resulting difference in sheet length to move.

The main is sheeted to the end of the boom. Measure the distance from the boom end at center line, to end of boom when full out. That is the amount of sheet line that you need the winch to bring in. Then do the same for the jib to figure how much line it needs to move.

What you may need to do is make a custom drum on a lathe, with a small diameter for the jib and a larger diameter spool for the main. That way, the winch winds in more line for the main and less for the jib, so both work together.

If you get an drum winch with ten turns, then you can calculate the diameter of the drum. The good news is that a long boom/sheet needs less power that the same rig with the sheet much closer to the gooseneck.

You can modify a powerful servo to continuous turns and connect it to (say) a ten turn potentiometer and set the custom drum on the servo.

http://www.servocity.com/html/hs-795...l#.U45omyiMf1U

Or get an RMG280EL and make a custom drum with the dia based on the number of turns that the winch provides.

https://www.rmgsailwinch.com.au/rmg/...ts/-280EL.html

John
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Old Jun 03, 2014, 07:51 PM
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Australia, TAS, Penguin
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Quote:
Originally Posted by hiljoball View Post
There are a couple of challenges to overcome. One is how much power, second is how many turns on a drum, and third is the difference in boom length between main and jib and the resulting difference in sheet length to move.

The main is sheeted to the end of the boom. Measure the distance from the boom end at center line, to end of boom when full out. That is the amount of sheet line that you need the winch to bring in. Then do the same for the jib to figure how much line it needs to move.

What you may need to do is make a custom drum on a lathe, with a small diameter for the jib and a larger diameter spool for the main. That way, the winch winds in more line for the main and less for the jib, so both work together.

If you get an drum winch with ten turns, then you can calculate the diameter of the drum. The good news is that a long boom/sheet needs less power that the same rig with the sheet much closer to the gooseneck.

You can modify a powerful servo to continuous turns and connect it to (say) a ten turn potentiometer and set the custom drum on the servo.

http://www.servocity.com/html/hs-795...l#.U45omyiMf1U

Or get an RMG280EL and make a custom drum with the dia based on the number of turns that the winch provides.

https://www.rmgsailwinch.com.au/rmg/...ts/-280EL.html

John
Good points John,

One way to get a lot of sheet travel would be some form of double haul. This results in twice the travel but half the hauling power.The RMG winches mentioned should be up to the job in any case, they will fold the boat in half given half a chance!
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