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Canting Bowsprit (on Steroids) Design Help  Bottom

  • Hi everybody,

    I'm currently hoping to build a Westport 25  beachcat this fall and one of the things I want to incorporate is a canting bowsprit.  The only bowsprits I've ever seen are either short -fixed or canting, or really long and fixed. What I'm thinking is a long canting: to mount the base on the main crossbar below the mast (puts the aft compression load directly where you want it) and have it run out beneath the forward crossbar. There would be basically a traveler on the underside of the forward crossbar thats attached to the bowsprit thus holding it up as well as controlling the side to side cant. So your more Slewing the Tip than canting it. The way I see it, this would let you pull the tack of a screecher (or even a Code-0) clear over to the windward bow and into cleaner air!  I don't know exactly how far beyond the bows is ideal for a screecher or Code-0, but it seems to me that around 6 feet is a reasonable goal to shoot for. Any thoughts?

    I also wonder (providing that the whole concept is sound) how much elevation the tip really needs. In pictures I've seen, it's quite high, but I think that may be to get a better angle for the guys. 
    If it doesn't require a tube too thick to do the job (2 to 3"), it would be nice if it could be unstayed

    What do you think??


    Best Wishes,
    Roston

    Here is a link to some of the few pics if found of the boat:

    http://www.boatersresourc…q22=&q23=&q24=&q25=&q26=
  • Friend of mine tried it on a Dragon Fly 25 tri the complexity verses gain is not worth it .. I had a modified Stiletto 23 with a 17.5 fixed pole and it was fine ... Ask your self this why do none of the racing cats or tris have it.. Simple as this kis KEEP IT SIMPLE ..



    Edited by George1067 on Feb 20, 2012 - 07:09 AM.
  • Getting the kite up and flying is the most important thing you can do, futzing with some obscure fine tuning will likely take time away from the kite up and flying. Get it all working first and then work on the little stuff. JMHO, YMMV, Ricardo.

    --
    Lake Perry KS
    H-18
    N-5.5 UNI +spin
    --
  • Funny, I am in the process of doing this on my Hobie Getaway. I am considering having it articulate to allow better down wind performance. Racers may not want to lose the time on tacks to play with this, but for recreational sailors it may be worth it, especially if you are doing long down wind runs. On short down wind runs it would be just as easy to gybe back and forth. They also don't have front tramps to worry about cluttering up. I want the pole below the tramp to keep it clear. I think your boat also has a forward tramp.

    The pole would need to be mounted to a modified V below the main cross beam. This would accomplish a few things, the front of the pole would be elevated to allow you to see under it. It would also help to keep from stuffing the tack and sail into the waves and it would also give you some space between the tramp and the pole, which would allow you to walk or lay on the tramp without hitting the pole below it. All of this depends on how much visibility you want, the water conditions you sail in, flat waters or open seas and how tight your tramp is.

    My thoughts on fabrication are as follows. Determine the length of your pole. Tie the pole to the forward spreader bar that your tramp is attached to. Allow the pole to hang 3" below the bar to compensate for any upward lift when the sail is loaded. Now you can determine the height at the forward end of the pole and the angle needed to get this height. At the aft end of the pole, measure how far below the main cross beam the pole needs to be to achieve this angle. This is the height of the modified V. This V would need to be flat at the bottom to allow a pin or bolt to attach to the bottom of it. The pole would rotate on this pin against the bottom of the V. \_/
    At the forward end of the pole attach two low stretch lines, these would pass through turning blocks at the outward ends of your front cross beam and continue aft to cam cleats on the main cross beam. These two lines would keep the pole from rising and would also allow you to control the position of the pole, center, port, starboard.

    I am not sure if my pole will articulate but it will be below the front tramp. I would like to here from anyone who has done this, or has a good reason as to why it should not be done. One last thought on this. I have also considered doing this with a 4' pole attached to the front cross beam instead of running it back to the main cross beam, but I am really uncertain as to how well the front cross beam would hold up, even if I reinforced it.

    Looking forward to any and all input on this.

    Vern
  • hobieflier
    I also wonder (providing that the whole concept is sound)
    http://www.boatersresourc…q22=&q23=&q24=&q25=&q26=


    I'm not sure the whole concept is sound. Not because of problems with the mechanism, you can probably work that out, although at the cost of many more control lines and complexity.

    The fundamental problem I see is that it sounds like you are trying to set your spinnaker/screecher to be able to sail directly downwind, which would be why you need to pull the tack to where it is not blanketed by the main and jib.

    That is how traditional yachts with symmetrical spinnakers and movable poles were sailed, but it's not how performance catamarans are best sailed. It's much faster to "heat up" downwind and jibe to where you want to go, and that type sailing doesn't need a movable pole.

    Build the boat as it was designed and resist the temptation to "improve" it without ever having sailed one.

    --
    Damon Linkous
    1992 Hobie 18
    Memphis, TN

    How To Create Your Signature

    How To Create Your Own Cool Avatar

    How To Display Pictures I…he Forums in the forums.
    --
  • Wow,

    This is the first forum thread I've started and I'm amazed by all the responses, [snifle, snifle] thanks guys. There are definitely a few fundamentals I hadn't fully considered. I've not had any real exposure to 'fast cat sailing doctrine' and   as Damon brought out, if done right, I guess canting really isn't needed.

    I love mechanics and over complicating thing :D so a reality check is always a good thing. Thanks guys

    Roaton
  • Roaton,

    Now that you've had a successful thread, how about introducing yourself? Where are you located and what sailing have you done? Please fill in your signature too.

    If you build the big cat you can have your own photo album here where you can upload build pictures and record the progress. You could also start a build thread where you could post updates for everyone to follow.

    --
    Damon Linkous
    1992 Hobie 18
    Memphis, TN

    How To Create Your Signature

    How To Create Your Own Cool Avatar

    How To Display Pictures I…he Forums in the forums.
    --
  • Ah yes, sorry bout that,

    I grew up and still live in Exuma, Bahamas. (someone send me a snowball!! :D)
    I started out sailing a salvaged Boston Whaler - 9 or 10 footer I think later had anytime-access to a JY15 of which I still have many fond memories. It was in 98 that I did some work in exchange for a hurricane battered H16 with a broken mast. I used another mast I had and stuffed it into the bottom two feet of the hobie mast. The entire rig was still too short and I spent the rest of my time with that boat rolling under the boom with every tack, (sigh) good times...

    I parted with that boat in 2006, when it seemed everything that could hit the fan did so - in chorus and sailing faded into the background. I got my next boat in 2010 - an old Flying Scot daysailor with a swing keel , which was good for the shallow south coast I had moved to.

    It wasn't until new years that a friend of mine : Dick Chase passed through Georgetown did I remember years ago he had offered to let me use the moulds he had to build one of his cats. I hopped a flight down to Acklins and had a BLAST sailing for three days on his tri 'Lucile' (which started life as a Westport 25 till he added a 30' center hull). By the end of that trip - which was picture-perfect in every way - I knew I needed a cat in my life again, so that's what I'm planning now - a build in Sep/Oct up in Westport Mas. and then sailing her back home.

    I've never sailed in the States before so just the trip back is something I'm really looking forward to.
    If/When I start building I'll be sure to post progress!

    Any of you guys up in that neck of the woods?

    --
    Roston McGregor,
    Exuma Bahamas
    (H-16 past)
    Walker Bay 8
    Orlando Clipper 13
    Morgan 41 O/I
    (Westport 25 Soon... :D)
    --
  • Hmm, I had started an identical thread on the 'Boat Design.net' just after I created this one here, and it's been an interesting conversation so far!

    For anyone interested:

    http://www.boatdesign.net…le-41880.html#post531574

    From what Eric Sponberg says, there are pros to be had on every point of sail.

    --
    Roston McGregor,
    Exuma Bahamas
    (H-16 past)
    Walker Bay 8
    Orlando Clipper 13
    Morgan 41 O/I
    (Westport 25 Soon... :D)
    --
  • hobieflier
    From what Eric Sponberg says, there are pros to be had on every point of sail.

    I'm not sure Eric understand you are talking about a fast catamaran.

    --
    Damon Linkous
    1992 Hobie 18
    Memphis, TN

    How To Create Your Signature

    How To Create Your Own Cool Avatar

    How To Display Pictures I…he Forums in the forums.
    --

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