Aftmast rigs???

Discussion in 'Sailboats' started by jdardozzi, May 28, 2002.

  1. michael pierzga
    Joined: Dec 2008
    Posts: 4,862
    Likes: 116, Points: 0, Legacy Rep: 1180
    Location: spain

    michael pierzga Senior Member

    I must admit that the thread became so long that I never saw this sailplan drawing. It is indeed an inovative way to carry sails. The beam of a cat could give you some decent sheeting angles . Id have to think about it for a while to comment. Also I have little experience with cats. What would be the typical AWA in which you would expect your sailplan to operate at its best ?
     
  2. brian eiland
    Joined: Jun 2002
    Posts: 5,067
    Likes: 216, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Apparant Wind Angles

    I don't see any reasons that it shouldn't operate at all comparable apparent wind angles as any std rig.

    I do believe that the leading edges of my headsails likely need be 'detuned' such that they don't produce too sharp of an incidence angle for the wind, and thus become to easy to stall the airfoil of the sail. Several experimenters have noted this problem including Bolgers aft mast rig. This actually could become a critical point to consider in designing/deploying this rig, and having the everyday sailor enjoy it. I've suggested a purely round (bulky) furling foil, which incidently furls the easist.

    Aero drag is the other limiting factor to its upwind performance. But do I really have any more total drag than a two masted cruising boat ??...I have no second mast, nor assoiated rigging.

    If I utililize an existing mast tube with its existing mainsail slot, couldn't I fly a piece of material (maybe even thin plastic) in it, that would greatly improve its aero drag characteristic, just as with a sail in this slot??

    Or how about if I had no mainsail slot but rather a custom mast tube, could I attach two thin membrans of rigid plastic material (or other) to either side of the mast such that they extended into the wake of the mast and then slid against one another at their tips to produce a nice teardrop foil shape overall. I've got a sketch of that around here some where...will have to find it and scan it.

    Meanwhile here is a top view with 3 different wind angles

    So yes same AWA as normal rigs.
     

    Attached Files:

  3. CT 249
    Joined: Dec 2004
    Posts: 1,709
    Likes: 82, Points: 48, Legacy Rep: 467
    Location: Sydney Australia

    CT 249 Senior Member

    You're right that high-aspect rigs aren't always all they are cracked up to be (IMHO), but on the other hand, there have been people with considerable long-term cruising experience who say that there are places (like south-east Australia) where going upwind, often for long distances, is almost inevitable and therefore a boat with good upwind performance is vital.

    The limited local cruising (and many deliveries) I've done has involved a lot of upwind sailing. In our typical summer breezes a boat that goes upwind well can spend a lot of time on the making tack, sailing almost parallel to the shoreline out of the current, with a short tack out to sea every few miles.

    The poor guys with boats that can't point end up sagging into the shoreline and tacking out regularly. And quite often it seems that high-pointing boats can go straight up the coast close-hauled, while those who can't point well are still tacking and falling miles behind or, more often, motoring.

    Even in smaller areas like the Whitsundays, upwind performance seems to be a great thing to have if you like sailing. The islands that are further upwind are normally much less crowded (in my very limited experience and apparently as a matter of course) because few people want to motor to them and few boats can sail to them effectively in the periods when the tide is not running strongly downwind. Last time I was there we made sure that we chartered a boat with good upwind performance, and watched many boats give up trying to sail upwind to islands, while we reveled in our Dehler slicing along nicely.

    The corollary is that good light- and medium-air performance is important, because if you can't sail well in light winds you end up sailing in when the wind is strong, which is a hassle in an area with notoriously rough seas. And the modern fractional rig, IMHO, is superb for all this stuff.
     
  4. brian eiland
    Joined: Jun 2002
    Posts: 5,067
    Likes: 216, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Radius, Aft Mast

    Here is another aft-mast design by a fellow Kees Radius. I originally saw this smaller boat in Holland years ago, and about a year or so ago he contacted me and sent some other pics. Thought I would post them here before I forgot about them.
     

    Attached Files:

  5. michael pierzga
    Joined: Dec 2008
    Posts: 4,862
    Likes: 116, Points: 0, Legacy Rep: 1180
    Location: spain

    michael pierzga Senior Member

    From a practical point...unboomed sails are very difficult to handle reaching , light wind in a seaway. They flop around and ruin there shape and angle of attack. I frequently sail with the main sail triangulated.
    Topping lift tight, mainsheet tight , preventer tight...to hold the sail at the correct angle of attack.
    The cutter rigged foresails are very effective between 45 and 100 awa but after that they blanket each other and since they are boomless...difficult to keep them quite and trimmed at sea.
    .On a cat, with its wide beam, you may be able to generate the leed angles to make it work...I cant see it working on a narrow monohull.

    Remember, you frequently Motorsail with Main sheeted and prevented to add speed and dampen roll.
     
  6. brian eiland
    Joined: Jun 2002
    Posts: 5,067
    Likes: 216, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    'Different' Sailing Rigs

    I guess since I've touted a 'different' sailing rig for such a long time, people find me to ask if I've seen this one, or that one. I've become a magnet for 'different rigs' considerations ;):D

    Here is one of those I just received recently . I'm posting it here because it does make primary use of headsails to drive the vessel, AND it was conceived by its 70+ year old owner for easy handling.

    By the way, check out the text in the lower jpeg image

    _________________________________________________
    Hi Brian...
    You may have already seen this rig, but just in case you haven't ...
    here is a link and some pics in attachment for you.

    http://thecoastalpassage.com/xit.html

    I don't know this fellow personally (John Hitch of Hitch-hiker cat
    designs) ...But about 3 years ago I saw his boat 'X-IT' (60 footer),
    parked here in the estuary at Laurieton NSW Australia... I thought
    that Earth had just been invaded... so I rowed my boat around this
    beautiful monster to see what sort of critter piloted such a craft...
    and there was a solid older gentleman (human) sitting on the back deck
    sipping on a cup of tea. (John Hitch), and because I didn't want to
    disturb him, I did not say hello. (which I now regret because from
    what I hear he is extremely knowledgeable and easy to talk to)
    From all reports this cat can easily do 20+... with only fore-sails
    (as you can see)
     

    Attached Files:

  7. michael pierzga
    Joined: Dec 2008
    Posts: 4,862
    Likes: 116, Points: 0, Legacy Rep: 1180
    Location: spain

    michael pierzga Senior Member

    Sure. The customer I presently work for is 81 years old. He pushed hard to eliminate booms and go with a schooner type rig. In the end the naval architect poo poo'd the idea.

    I believe it will work fine...if your prepared to accept its shortcoming. Inshore...flat water, day cruising would be a very good application
     
  8. Guillermo
    Joined: Mar 2005
    Posts: 3,644
    Likes: 189, Points: 63, Legacy Rep: 2247
    Location: Pontevedra, Spain

    Guillermo Ingeniero Naval

    I totally agree it is most desirable to have reasonably good light air performance and weatherliness abilities in a cruising sailboat. Not all cruising is mostly passagemaking for most of the people, but rather involves a lot of coastal cruising. In such environments having a good upwind performance may prove not only convenient but vital.

    I love my good old heavy and undercanvassed motorsailer Marie :), but I have to recognize I would like her to have more sailing abilities and not depend almost exclusively on motoring except when in force 4+ open rhumbs....
     

    Attached Files:

  9. michael pierzga
    Joined: Dec 2008
    Posts: 4,862
    Likes: 116, Points: 0, Legacy Rep: 1180
    Location: spain

    michael pierzga Senior Member

    Ahh..."Marie" is a beautiful boat..... ketch rigged motorsailors with great big sun awnings rigged for burning hot Med afternoons . Mizzen and genoa set...cruising under the big awning , in the shade, while trolling for Lampuga ...AHHHHHHH. I also like the fisher motorsailors. When I grow up Im gonna get one !!!!!!!!!!!!!!!!

    I would think that with attention to detail in sailplan and underwater surfaces that classic chunky, lets enjoy life, motorsailors could be much more lively when sailing.
    Dont think that an aft oriented rig would be practical for day to day cruising simply because all the rigging is aft and intruding upon prime living space. Also the incredible practicality of a for and aft sailplan like a ketch would be missing. Guillermo's "Marie" under tightly sheeted mizzen to dampen role is a desirable feature.
     

    Attached Files:

  10. pbmaise
    Joined: Jul 2010
    Posts: 115
    Likes: 5, Points: 18, Legacy Rep: 80
    Location: Cebu the Philippines

    pbmaise Senior Member

    Philip Maise's Aft-Mast Rig With Crab Claw Sails - Second Sea Trial Results

    Aloha All
    I've completed round two of my sea trials and attached a detailed writeup.
    I also shot two videos I've posted on you-tube. See these links.

    http://www.youtube.com/watch?v=4JSH1s6aGEQ
    http://www.youtube.com/watch?v=XAVFh2heetA


    In brief I am showing the boat self-tacking and headed windward. Here in S.E. Asia I continually learn from other sailors that nobody sails around here. Either there is no wind, or nasty short lived squalls that can leave you demasted. I demonstrated that all too well. You may find it odd, however, it was kind of a relief. I knew based upon my first trials that I was in essence putting duct-tape over problems that could only be corrected by starting the mast design again from scratch.

    I'm excited at looking at this problem with a fresh eye. I can't wait to see what I come up with. Now don't laugh...for some reason I think a mast should be more like a sculpture.

    Well more on that later, I'm going home for the Holidays.

    Miri Malaysia is a good safe place to leave my boat and so I bid you guys good bye for a while.

    Philip Maise

    p.s. If anyone is excited about what I am up to and wants to take this project on from here or partner with me...I'm all ears. I'm not really good at marketing.
     

    Attached Files:

    Last edited: Dec 7, 2010
  11. RHough
    Joined: Nov 2005
    Posts: 1,792
    Likes: 61, Points: 0, Legacy Rep: 793
    Location: BC Summers / Nayarit Winters

    RHough Retro Dude

    I agree 100% Our Whitsunday chartered cat had no upwind performance to speak of. I think we sailed 3 days out of 7. We still had a great time and I wish other cruising areas were as friendly! I can only imagine how much nicer it would have been if we could have actually sailed!

    Light air performance requires either light weight, large sail area or some combination of the two. It might mean reefing at 12 knots, many cruisers are so intimidated by the thought of reefing they would rather have little sails and motor when its light. Ad to that the macho idea that a "good" boat can carry full sails in to the high teens or low 20's and boats that reef in 12-15 are looked at as "tender" and not fit for cruising ... :(

    Average wind strength on the oceans is about 10 knots. If you design a rig to be fully powered in 10 knots, you will be reefed in the trades or you need to be able to set light sails. Schooners and Ketch rigs are good for this, but a tall fractional with a well thought out reefing system or in boom roller reefing would be less work and more weatherly (while retaining good reaching performance)

    How about a 3/4 fract rig with a big roach roller furling main and a light air masthead flying sail on a continuous line roller? At about 10-12 true you roll and douse the flying code zero and you have a manageable 10-16 knot rig at full hoist and a darn good rig reefed in 15+ Three sails plus an A-Sail for broad reaching in medium air ...

    R
     
  12. Fanie
    Joined: Oct 2007
    Posts: 4,604
    Likes: 177, Points: 63, Legacy Rep: 2484
    Location: Colonial "Sick Africa"

    Fanie Fanie

    Awesome Philip !

    Just one thing, the crab claw (clew) line to the mast rides high. I think you may improve power (and speed) if you make the leech radius smaller by pulling the sail foot down. The sail would be flatter then. I have found it to make quite a difference.

    It would be interesting to know what angle you got from wind in the sail on starboard to again wind in the sail at port. I have found the smaller the angle to wind the less speed I had, but just increasing the angle a bit made a lot more power.

    I'm impressed anyway. Very nice going and it's going to come together. It would also be interesting to see how far back your mast sits in the hull.
     
  13. Fanie
    Joined: Oct 2007
    Posts: 4,604
    Likes: 177, Points: 63, Legacy Rep: 2484
    Location: Colonial "Sick Africa"

    Fanie Fanie

    Which made me think if you do land in a storm with high wind and you sail closer to wind you may make less speed but without additional stress on the rig (if you're not going to furl it some).
     
  14. michael pierzga
    Joined: Dec 2008
    Posts: 4,862
    Likes: 116, Points: 0, Legacy Rep: 1180
    Location: spain

    michael pierzga Senior Member

    Yah, I reef in about 13 knots true, upwind, on a multi purpose cruiser. By reef I mean strike the Genoa, shift to staysail. At 15knot true Im fast, full main staysail..AWA 35, normal sea state.

    No data supplied on the aft mast rig concerning wind angle ,wind strength and boat speed ? Difficult get a grip with whats going on.
     

  15. BATAAN
    Joined: Apr 2010
    Posts: 1,614
    Likes: 101, Points: 0, Legacy Rep: 1151
    Location: USA

    BATAAN Senior Member

    When I was building my modified SPRAY-type, BERTIE and designing her rig a fellow named Bernard Moitessier used to drop by the boatyard. He was living in town aboard his steel cruising boat and told stories about sailing around the world single-handed and all the problems that come up. He had grown up in Vietnam and explained a lot to me about fully battened lug rigs. One thing I really gleaned from him and other experienced voyagers like Sterling Hayden and Irving Johnson who I knew at the time was that a great deal of ocean sailing is done in 5 knots of wind or so, especially in the Pacific, and any serious cruising boat must deal with this. That means large sail area and a vessel that is not too overloaded. BERTIE is a cargo design, so eats tons of supplies with little outward effect, and her 1000 sq ft chinese-lug mainsail is a wonderful ghoster, making light sails not very necessary.
    The second photo is the 1901 GOVERNOR M.B.M. on the beach for a scrub and paint. She's being re-rigged as a schooner and the foremast is not made yet. We sailed this boat quite a bit with a schooner gaff main and 3 headsails and it worked OK. We could tack and jibe, whatever was needed. Much better with the fore mast in though.... She ended up in Hawaii.
     

    Attached Files:

Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.