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Author Topic: loop control  (Read 2183 times)

LarryW

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loop control
« on: January 24, 2014, 12:28:27 PM »

 Hi ,
                  Need help on loop sail control ,   to control sails on Bixham Trawler , is there diagrams or drawings out there[size=78%] ..?..[/size]
[/size][size=78%]                       OR SAIL ARMS [/size][size=78%][/size]EASIER..?..[size=78%][/size][size=78%]     [/size]something[size=78%] to do while getting over pace maker op [/size][size=78%]
[/size][size=78%]     cheers Larry..[/size][size=78%]
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mrpenguin

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Re: loop control
« Reply #1 on: January 24, 2014, 01:04:32 PM »

Hi ,
                 
Need help on loop sail control, to control sails on Bixham Trawler, is there diagrams or drawings out there ..?..
OR SAIL ARMS EASIER..?..
something to do while getting over pace maker op

cheers Larry..

Hi Larry,
I think the gremlins got at your post, I have reformatted it, hopefully we still have what the meaning is....

Firstly there is a thread here that may be of some value:
http://www.modelboats.co.uk/forums/postings.asp?th=90191

Also a nice video here that may be of help
http://www.youtube.com/watch?feature=player_detailpage&v=jXfI2qIL5Ew

You have not indicated the scale you are working in, so the following is a generalisation...

Assuming you need to develop the sail control system from scratch yourself, the first step would be do determine how much sheet travel you will need from close hauled to sheeted out. This will be a function of the distance from the pivot point of the sail (the mast in most cases) to the sheeting point - you will be limited on where you can do a fairlead because of cabins etc.

I am guessing, from looking at the video and pictures that the sheet control is only on the larger sails. The layout of the boat implies fairly long sheets I would think.  the foresails may perhaps be self tacking... if they need to be winched as well, they will require far less sheet travel, perhaps a separate winch. They would also require much less torque due to the smaller sail area.

Once you have the sheet length, you can start planning. Next step would be to have a think about how much torque will be required - these big sails will take a bit of hauling. Assuming a combination of a good bit of sheet travel and a fair bit of torque, I would think a drum type winch rather than an arm type winch would be the go. The drum type winch will transport far more line (example - perhaps 300mm) compared to an arm winch. A drum winch will transport the line more slowly, this is not necessarily a problem.

The best method (in my opinion) if you have the room is to set up a continuous loop system, preferably below decks, with the sheets connected to the endless loop at appropriate points

Have a look at this video of a winch I did on a cheap Chinese boat; while it is a very different boat the principles are much the same...

Hope this helps...
http://www.youtube.com/watch?feature=player_detailpage&v=JWhI3F_MY74
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LarryW

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Re: loop control
« Reply #2 on: January 24, 2014, 04:05:17 PM »

Hello mr pengquin. Thank you for reply ...
             my hull length is32in ned to all under deck have 2 1/2 turn winch,
 all the links came up as errors so will try later ... I have seen your posts on another web site in aus  which i use my name toylander ,
              not a lot help to me,...     as seem to favour local lads ...
              have and    sail much modified SURMOUNT  with fully closed guided winch ,. with adjustable   sheets and shrouds,   
                      cant do much  at the moment just had pace maker fitted ,.
                                6 week before any modelling so brush up on anything to get started on Brixham.....
   thank you for input     cheers Larry...
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hammer

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Re: loop control
« Reply #3 on: January 24, 2014, 07:30:36 PM »

Larry get well soon. I have ticker trouble too also have a trawler. I hope you can follow the drawing. In the hatch the red arrow points to the return pulley which is spring loaded. The drum servo is right forward under an other hatch. The mizzen sail only needs half the movement of the main.The blue arrow to the sail arm controlling the  stay & fore sails. The fore connected 1/2" in from the stay to reduce movement.  The yellow arrow points to a drum servo to raise & lower a centre plate (not really needed.) The white to rudder servos. Yes two but you will only need one, the other doubles the size of the rudder when in the water. Trawlers do sail well, you will enjoy.
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LarryW

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Re: loop control
« Reply #4 on: January 28, 2014, 02:10:00 PM »

  hello all thank you for info,
    Hammer , what winch did you use,        how is the spring located , any more drawings..?.. cheers Larry..
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hammer

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Re: loop control
« Reply #5 on: January 28, 2014, 09:24:34 PM »

Larry. I used Hitec servo can't remember the number, as the boat is 10 years old.
I forgot to say the strings are in a trough where it is under the deck.
Below the drawing of the return pulley. Top plate not shown.
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LarryW

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Re: loop control
« Reply #6 on: January 29, 2014, 11:41:06 AM »

 
         Thank you for drawing,
 winch is a good one ,      just got work out how many turns to pull in sheets and attachment points , still on a learning curve  ,
           will knock up a test bed something to do while recovering from surgery  .......cheers Larry,,
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