Put a square rigged sail on a W/A??

Discussion in 'Propulsion' started by paulfish, Sep 19, 2012.

  1. paulfish
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    paulfish paulfish

    Or am I crazy? The scenario: Have a 1983 Proline 23' w/185hp OB,wt 2700lbs( With engine),walk around cuddy,displacement not known. Want to mount a mast forward of the windshield going through the cuddy top and flanged to the cuddy sole.Booms-one aloft and one low. Mast can pivot to 45 degrees. Square rigged sail(most efficient? and simple). Approx. 325 sq. ft. sail based on formula I saw waterline squared X 0.75. Simple rudder as lower unit of OB would just cause drag. Grommeted sail with simple pulley rigging.Questions:1) Booms and mast aluminum-what non marine tubular aluminum to use as masts are expensive.2) What sail material? Using just polytarp for initial shakedown.3)What kind of forces would be placed on the mast/booms so how strong an installation is needed.4) With a 45 degree pivot can I make a semi effective tack? 5) Will the hull be subject to a lot of roll or yaw under sail? 6)What kind of speed? ie. could I get 5kts. from a 15mph wind? Just want to try it. If it fails the mast/booms become outriggers and a straight gaff. The polytarp "sail" becomes well just a tarp. Any ideas oh smart and savvy mariners?
     
  2. Petros
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    Petros Senior Member

    why? I would not bother, that boat is totally unsited to retro fit sails. It would be a frustrating waste of time and money. You would only be able to go downwind, and you will be lucky if you could control it. A sailboat is a complex interaction between water, hull, rigging and control surfaces, that kind of hull is not going to take well to having a sail attached to it. a square rig is not very efficient at all (that is why they have not used them for over 100 years), the hull on your boat will have way more drag than one designed for sailing, it has no suitable keel to resist the lateral forces, no effective rudders at all for the very low speed that a small sail will push it.

    For much less messing around you can go buy a used sailboat off craig's list and go enjoy it. Learn something about sailing a proper sailboat before you attempt something like that.

    I had a friend that was given a similar boat as yours, very weathered and beat up. After he was board with putting around on the local lakes with an undersized engine, he built a wood mast and yard and installed a heavy canvas sail (tarp would have worked better), and dorked around with it a whole season, and than never really used it much. Best he could do was motor to the up wind end of the lake, hoist sail and drift back to where he started.

    In your case you would damage the deck and possibly hull of I presume an other wise good boat, spend time and money and devalue what you have now.

    Do not even bother, sell it and buy a proper sailboat, use a motor on it if you want the option of motoring around.
     
  3. paulfish
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    paulfish paulfish

    why not?

    Of course I'm aware of the dynamics of sailboats as regards keel,hull,rudder etc. Didn't want to make a good sailboat just a powerboat that can move under sail. Can you take a stab at the questions regarding masts/booms/materials? The goal is to have some fun with a project and I'd be truly happy . As a fishreman who spends many long and noisy hours running to and from the fishing grounds the notion of some movement under a quiet sail has a real appeal for me.
     
  4. Petros
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    Petros Senior Member

    do not use a square rig. easiest to control would be to put a cantilevered mast with a simple junk rig. loads are low, and it will be much more efficient than a square rig, easier to control and drive the boat better.

    Next would be a simple cat rig, or possibly a balanced lug rig. A square rig is really a bad idea.
     
  5. masalai
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    masalai masalai

    Hi paulfish,
    Ask yourself this question - WHY???????? do a SWAT analysis (normally used in preliminary business evaluation) but relevant here - answer it yourself and post your own answer here and impress everyone of your lateral thinking and analytical skills...
     
  6. FMS
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    FMS Senior Member

    What is the fastest speed you need under power paulfish?
     
  7. paulfish
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    paulfish paulfish

    Thanks Petros. I'll google those terms-it's at least a starting point. Masali-don't feel the need to do a "SWAT" analysis here nor am I out to impress anyone with my cognitve acumen. I believe you meant SWOT and the only strength I see is in having fun, the weakness I perceive is not enough vodka in my martini, the opportunity is to drink a martini under sail and the threat is spilling my drink when I hit a boat wake. Cheers!
     
  8. paulfish
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    paulfish paulfish

    FMS, I don't have a fastest speed requirement. I fish and my only need is to attain a speed to get me offshore in a reasonable amount of time. I cruise with good conditions at about 27kts. To have a sail is not about speed,it's about pushing along quietly and enjoying the water. Why do you ask?
     
  9. Petros
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    Petros Senior Member


    Well, you did ask.
     
  10. paulfish
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    paulfish paulfish

    Hello Petros, Found a site called Duckworks where a guy had plans/instructions for a junk rig made with polytarp no less. I see the logic of it and the cantilever. Easy to manage and not hard to build. The cantilever. It reefs easily,doesn't luff or flap badly,doesn't require a lot of strength in the material due to the sections(jacks?) and well suited to motor sailing per one design site. Also says it's a fairly easy sail to manage and safer since it reefs quickly and can be partially reefed as needed. My wife will be thrilled as she is from Tianjin, China which is a port city.Thanks again or as is said in Mandarin "xie xie ni gei wo bangjiu" or "thanks you give me help"
     
  11. gonzo
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    gonzo Senior Member

    If you troll in salt water, your speed should be 4 to 6 knots. To achieve that, it will take a rig comparable to a high performance sailboat of the same length of your Proline. The reason is that the drag of that hull is huge compared to a sailboat. Therefore, to reach 5 knots it will take a fairly huge rig. The problem with a huge rig is that the stresses and heeling moment will likely break your boat or capsize it. However, if you want to go 1 knot or so, it is doable.
     
  12. paulfish
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    paulfish paulfish

    sail on a W/A

    You can troll at 1 kt using parabolic rods with bunker spoons and stem the tide or tuna troll at 12kt with jap feathers but that is neither here nor there. The question is can a sail push the boat downwind faster than 1kt? Of course the boat will skid as it has no keel. Seems it would be impossible to lose the heeling moment at low speed especially given the large beam to length ratio on a planing hull. How could the boat "break"?
     
  13. whitepointer23

    whitepointer23 Previous Member

    you have come to the right place if you want to be told what you can't do, i understand you just want to have some fun without spending a lot money. ignore the scientific arguments and give it a go. have you thought about a kitesail, they are easy to set up and are a serious proposition for emergency propulsion if needed.
     
  14. paulfish
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    paulfish paulfish

    Thanks Brendan, Yes, the whole notion of using sail started when I read some articles about kite sailing. I see that you know where I am coming from. Could you throw me some information/pointers or direct me to where I might find some information? Mostly just stuff about materials etc. Have fun,not spend too much money is the idea. However do I sort of enjoy being told what I can't do and then doing it.
     

  15. whitepointer23

    whitepointer23 Previous Member

    there is a video of a 24 ft cruiser under kite sail. i don't remember what site it was on but you should find it on google, i think there is a thread on the subject on this forum.
     
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