Model Boat Mayhem

Mess Deck: General Section => Model Boating => Topic started by: Microyacht on November 29, 2006, 11:24:00 pm

Title: HUGE Sail Winch?
Post by: Microyacht on November 29, 2006, 11:24:00 pm
Are there any HUGE Sail Winches available?

My sail area is 8 sq ft and I need to pull the mainsheet about 24"  . . . it's a BIG boat.

Many thanks
Title: Re: HUGE Sail Winch?
Post by: tigertiger on November 30, 2006, 12:05:43 am
Are there any HUGE Sail Winches available?

My sail area is 8 sq ft and I need to pull the mainsheet about 24"  . . . it's a BIG boat.

Many thanks

Not a sail winch, but a sail servo. The HItec 815BB has 19.6gm/cm torque on 6v.

Victor models recomend it on their Valkyrie model, which is 800sq in. Only about 70% of what you quoted.
http://www.victor-model.com/valkyrie.html

Title: Re: HUGE Sail Winch?
Post by: JayDee on November 30, 2006, 12:18:50 am
Hello,
Why not use TWO winches on a "Y" lead?.
I have two winches on my schooner, one for the Mainsail and one for all the others, very easy to set up 2 winches, using just one could be a bit iffy !.
What is your boat?, that is a lot of sail area !.
John,  ???
Title: Re: HUGE Sail Winch?
Post by: JayDee on November 30, 2006, 12:36:00 am
Hello,
Just had a look at your Website, a 1/3 scale model of the Puffin, gives a Hull length of just over 2.5 feet, but with a big, high sail.
Is this model to be the prototype and test model for the real boat?.
If so, how do you propose to stabilize it, does it have a deep keel and ballast?.
John.
www.john-dowd.co.uk
Title: HUGE Sail Winch?
Post by: Microyacht on November 30, 2006, 12:37:12 am
Quote
Not a sail winch, but a sail servo. The HItec 815BB has 19.6gm/cm torque on 6v.

Victor models recomend it on their Valkyrie model, which is 800sq in. Only about 70% of what you quoted.
http://www.victor-model.com/valkyrie.html

The amount of torque may be "Just" adequate but it was not for my smaller Kon-Tiki catamaran. The main problem with any sail arm servo is the length or "pull". I need to take up something like  24" of mainsheet but I guess this could be reduced by attaching further down the boom?

The boat is a 1/3rd scale model of a larger "Full-size" boat that I will be making next year.  The model is now almost complete and it's purely to test before making a mould for the larger one.

Many thanks . . .

If all else fails, I could make up my own using a H/D geared motor and fit it to a large "Slider" pot and use then electronics out of a standard servo.
Title: Re: HUGE Sail Winch?
Post by: Microyacht on November 30, 2006, 12:38:56 am
Quote
Hello,
Just had a look at your Website, a 1/3 scale model of the Puffin, gives a Hull length of just over 2.5 feet, but with a big, high sail.
Is this model to be the prototype and test model for the real boat?.
If so, how do you propose to stabilize it, does it have a deep keel and ballast?.
John.
www.john-dowd.co.uk

It's got 10lbs of lead at the bottom of the keel!
Title: Re: HUGE Sail Winch?
Post by: Telstar on November 30, 2006, 01:35:31 am
Hi Microyatch
I modded a Hitech 765hb to give 6 turns, with a total length of sheet in of about 30 cm the drum was just 2 cm dia. perhaps with a larger drum say 4 or 5 cm.  The mod was straight forward and cost me £6.50 for bits

Tom
Title: Re: HUGE Sail Winch?
Post by: andywright on November 30, 2006, 07:43:12 am
RMG make some powerfull winches, contact Neil Rothwell -     Landline 0117 961 5497
mailto:[email protected]
Andy
Title: Re: HUGE Sail Winch?
Post by: cbr900 on November 30, 2006, 01:02:27 pm
Or you can use a cordless drill motor, take off the chuck and add a nut to hold the winch drum, I use one on my A Class yacht with great success, you can also use the screw setting adjuster as a stop for the distance you need to travel....




Roy
Title: HUGE Sail Winch?
Post by: Microyacht on November 30, 2006, 06:32:06 pm
Thanks for all the intersting ideas. I don't at this stage want to spend a fortune on the sail winch.

I've looked at RMG and they look to be the best but at a price that for this project at the moment is to expensive. The modified Hitec HS765Hb looks to be the easiest way out a reasonable cost. I've modified servos to give a much greater swing before by fooling the feedback pot with extra resistive padding: http://www.kon-tiki.freeserve.co.uk/catamaran/sailwinch.htm (http://www.kon-tiki.freeserve.co.uk/catamaran/sailwinch.htm). A drum fitted to a cordless screwdriver will lift a house! They can be easilly controlled using the PCB ripped out of a standard servo + an extra driver transistor. As I already have 2 or 3 cordless screwdrivers . . . I may donate one or maybe do it later for a future craft.

Thanks again . . . . .
Title: Re: HUGE Sail Winch?
Post by: Microyacht on December 13, 2006, 09:11:16 pm
Well, this it what I did. Tom (TELSTAR) suggested modifying a Hitec HS-765HB by adding a home made drum and changing the feedback pot from the standard 5K potentiometer (270° or less rotation) to a 10-turn pot.

I made my own simple drum using 2 standard H/D white plastic discs and some M3 spacers: