Aftmast rigs???

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

  1. michael pierzga
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    michael pierzga Senior Member

    Yes Indeed Bataan....the ocean crossings yacht do are light wind. Big clouds of reaching sail are needed if you expect to turn the motor off. Unfortunatly many boats are under canvassed.
     
  2. brian eiland
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    brian eiland Senior Member

    I don't understand what you are saying? Haven't you read that this rig could be sailed under genoa/mizzen as well as under 'staysail' alone. And of course with todays materials that genoa could be roller furled to half its size

    The single staysail configuration was thought to be applicable when trolling for fish under sail, as well as higher wind situations. The centers of effort remain balanced over the hull.

    Wing and wing downwind for those cruising sailors that don't want to be bothered with fancier downwind sails, or those that want some piece of mind at night when short handed, and/or the recognition of foul weather might be more problematic.
     

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    Last edited: Dec 10, 2010
  3. cavalier mk2
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    cavalier mk2 Senior Member

    Very interesting. I was contemplating a a-frame mast for proas and realized that a mast offset sideways rig would do the same job with a furler in line with the mast towards the boat center for a main and a jib furler on an arced track so it wont bend the foil for shunting to each end to save having to have 2. It would be tensioned on each shunt/tack and eased for the shunt. Rolled it would be easy to handle, fitted to a track car it could be towed each way and controlled from the cockpit. Of course stays to the bows/ends and a stay to the ama (Pacific proa) and stay to the main hull by way of spreader. Any thoughts? The karman vortex street concept of the a frame I understand but think it might be diminished by the flow pattern channeled by the sails. A single mast of course would be lighter. So this is the equivalent of a proa mast aft rig.
     
  4. Guillermo
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    Guillermo Ingeniero Naval

    Most true! [​IMG]

    (Sorry Brian. Couldn't resist...:))
     
  5. brian eiland
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    brian eiland Senior Member

    Aft Mast Powersailer, the second one

    The second Hong Kong 40 Powersailer has been launched a few days ago, and there are updated photos on that referenced webpage.

    The builder sent along this note,
    "Yesterday they were sailing to Kho Chang with 6.9 knts speed with only one sail. Top speed is 9.5 knts with 2 x 50 hp"
     

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  6. brian eiland
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    brian eiland Senior Member

    Doesn't appear as though that mast and rigging is really intruding on the living spaces.
     

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  7. pbmaise
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    pbmaise Senior Member

    Comparing Maise's Aft-Mast Rig to Wishbone

    My apologies Brian,

    I missed your questions till now.

    I followed the links and will attempt to answer your questions.

    This boat builder built his mast to fly two fore-sails at different heights up the mast. So did I. In his case he went with roller furler sails which had camber and no spars in the feet. His sails drove the boat both forward and down. In my case i went with what I have been calling crab claw sails since my sails have zero camber and spars in the feet. These drove my boat both forward and upward and allowed me to self-tack. This is something he couldn't do on his boat.

    I think we can assume by the after photo that this boat builder also suffered from a mast failure. Either that or he cut the mast down after doing sea-trials. In his case it appears the failure or mast reduction occurred above the mid-way point. His side column support looked excellent. I like the length of his spreader bars and the fact he went with a second set of spreaders 3/4 of the way up the mast. The area the before picture appears to be int he same area that my support was weak. It is the roughly 45 degrees behind the mast that is key. Had he switched from one back spar, and two spreaders mid-way up his mast to two back spars at 45 degrees behind his mast we probably would still be flying with the original mast size.

    I have some doubts about the after photograph. I can clearly see a line going up into the sky in front of that roller furler. It obviously attaches somewhere, and the photograph is not showing the entire picture.

    This said, we must now interrupt that is going on with that sail in the second photograph. Unquestionably it is odd. It reminds me of a windsurfer and how a windsurfer uses something we also call a wishbone to spread the sail apart. A windsurfer holds onto the wishbone when sailing. Wishbones are also used on other sail boats to hold the sail away from the mast.

    Unfortunately we have been calling this mast design wishbone too. Perhaps to prevent confusion we should only refer to this type of mast as a-frame.

    Back to the sail. It looks to me like a kite. A good old Charlie Brown get stuck in the tree kite. The innovation is that it looks like he just can unfurl it from that roller furler and and away he goes. Well, how fast he goes and how he controls this sail is beyond me. Sorry.

    Regarding my own rig. I think I will be going with a carbon fiber mast from DK Yachting of Melaka Malaysia. However, it will take a few months to build and install. Except for the sand flies, Miri Malaysia is a good place to be based. Its nice to simply walk off my boat and down the road to a five star hotel and the local shops. At Ao Chalong it was always a trek.

    Regarding the question whether my sail is better described as being lateen or lanteen, does it really matter? In all the links I see about lanteen and lateen the foot doesn't have a spar. It is a vital part of my sail which why I prefer crab claw.

    Philip Maise

    Phil
     
  8. brian eiland
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    brian eiland Senior Member

    Speaking of Lee Shore Mishaps

    The headline-grabber for the week was undoubtedly the Phuket King's Cup, which ended last Saturday with no less than 12 boats on the beach at Kata after a wild night of westerly wind and swell coming straight in from the Adaman Sea. And this after a King's Cup that is more likely to be remembered for indifferent weather than anything else (except the beachings).

    12 grounded boats is quite a big deal, really. The multihulls just got carried up the beach beyond the high water mark to wait for more clement conditions and a re-launching, but the monohulls suffered a lot more. Judging by what we saw, there will likely be some write-offs – what the insurers call TCL, or Total Constructive Loss.

    http://www.sail-world.com/Newsletter_show.cfm?nid=460575

    Sounds like the multihulls faired very well
     
  9. CT 249
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    CT 249 Senior Member

    Reports say 12 boats grounded. Of them, five were multis. So if we want to try to learn things from this unfortunate event, we could note that 26% of the multis entered in the event hit the beach while just 9% of the monos hit the beach. In this case, there was a nice beach to leeward, but that's not always the case.

    In Phuket, there was a beach of convenient size. In the recent Airlie Beach (Australia) cyclone, the shallow draft of the multis allowed a couple to float over the beach and into the seawall, where at least one suffered severe damage. Monos that went aground beside them may well have done better (or so it appears from the pics) because they stayed on the sand below the seawall.

    http://forums.sailinganarchy.com/index.php?showtopic=105907&st=75

    Different situations suit different boats. There are too many variables in such a situation to draw much of a lesson, surely.
     
  10. pbmaise
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    pbmaise Senior Member

    There is zero excuse for a single boat to have gone ashore in this bay. The bay is huge, it is shallow as far as 1 mile out and has all the room in the world to house this many boats safely. I know I've been there.

    I own a multi-hull that is perhaps bigger then all the ones that drifted ashore. At 65ft long and 40ft wide I follow basic safety practices like:

    1. Never leaving the boat without someone aboard who knows how to start engine, pickup anchor, and motor to safety.

    2. Always having an anchor alarm on to alert us to movement, and sleeping beside said alarm at night.

    3. Never depend on a mooring line unless it was specifically designed to handle the load of my boat, and it was tested under rough conditions WHILE someone was aboard.

    These irresponsible owners were too close to shore so they could easily go party and go to the bar. They also probably all went ashore leaving their boat unattended. Further, it is said, many removed their heavy anchors and chain for racing purposes.

    Any insurance firm that approves a claim in this incident is doing nothing but driving up the cost of insurance of responsible boat owners and rewarding the fat cats that view sailing as a good party.

    Now. Back to the subject of our thread. Thanks Brian for the great pictures of Hong Kong 40. I think boats like this will accelerate the movement to aft-mast rigs. I also caught your picture of the cat designed by Radius. Comparing these two boats side by side you can see quite a difference in how designers think the mast should cant. I'm obviously more along the thinking of Radius.

    I've been in Miri now two weeks and have been working on a new aft-mast design concept. I want to still use the sails and believe I am onto a winner there. Being right alongside dock has also been a blessing in that I finally have a chance to go from end to end of this boat and unload some of the thousands of pounds of excess weight. You wouldn't believe what the old owners accumulated over the years.

    To say I was carrying around a lot of sh.t would be both truthful and an understatement. Both of my blackwater tanks have been full since the day I bought the boat a year ago. I broke into the tanks via the vent line and inserted a tube to manually pump them out. I figure i have decreased my boats weight by almost 70 gallons times 2 times 8 lbs/gallon or about 1120 lbs. (And I've been chiding myself for carrying 5 kayaks at about 40 lbs each Or 200 lbs.)

    I've been seeking quotes for a new mast out of carbon fiber, however, given the fact that i can reduce weight in the boat in so many other areas I don't see much point in this route based upon weight savings alone. Therefore, I've located a source here in town for kiln dried lumber and may build from wood again. Of course I would be incorporating what I learned last time.

    Philip Maise
     
  11. brian eiland
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    brian eiland Senior Member

    Mono vs Multi grounding

    I really don't see how this satistical analysis has any meaning in this situation.

    Likely we all assume that the multihulls with their very shallow draft will 'park' as close to the beach side festivities as possible, and particularly off of a sandy beach. In fact close enough to even get out and walk to the beach rather than dinghy. Come to think of it, they are racing in this event, and many of the vessels are likely not carrying their dinghys, but rather relying on the locals for rides to the beach. At any rate we all know how the surf picks up as it nears the beach. So I'm not surprised that more of the multi's were washed up on the beach.

    But then, which of these vessels would I have wanted to be an owner of??

    .............(photos courtesy of Sail-World.com, Asia News,'Guy Nowell/Phuket King's Cup 2010')
     

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  12. brian eiland
    Joined: Jun 2002
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    brian eiland Senior Member

    With well over 300 boats in this race, you can imagine the logistical problems of getting to shore from all of these boats (most not carrying their dinghy). We simply anchored the Stiletto 30 right off the small beach next to the college boat house and wadded ashore thru a foot or so of water.

    On another occassion I did the same with a Louisiane 37 catamaran that drew 19 inches of water with the CB's up and the rudders kicked up.

    Come to think of it I took that same Louisiane 37 down along the backside of the outer islands of Cape Hatteras, NC (there were times we were pulling the boat along while walking the shallows....what a great trip that was). I'm sure there are not many boats of that size that have ever made that trip.
     

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  13. CT 249
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    CT 249 Senior Member

    I'd have thought that statistics are of great meaning when dealing with major issues, or else we can always just write off every lesson as a one-off.

    Mainly, it's a matter of trying to get away from the multi v mono issue. Surely it is reasonable to point out the context of your post about the situation of the boats that ended up on the beach.

    Yes, if I was one of the owners of the boats that hit the beach, I'd rather I owned a multi. But if I was one of the others of one of the boats IN THE EVENT, I'd rather it didn't hit the beach at all - and the chances of not hitting the beach were higher for a mono in this case.

    Yes, the shoal-draft craft were probably anchored well inshore because they could be - that's great, it's an upside of shoal-draft boats (whether mono or multi). But if (as you say) in this case it comes with a downside (less room for dragging before hitting shore, more chance of being in the surf zone) then surely we should not just put our hands over our eyes and ignore it, should we?

    My dreamboats are all centreboarders, so I don't think I'm biased against them, but can we ignore the downside when it is represented by an incident like this?

    Note also that according to those who were there and posted on SA, many of the strandings were caused by a boat that came loose or dragged, struck anchored yachts and cut their anchor lines (which were often down to heavy anchors that were left on the bottom and buoyed while the boats raced). Therefore there is a very significant random factor that caused many of the mono strandings. If a single multi had come loose and cut the mooring lines of other multis that then ended on the beach, would you use that as example to show that multis faired poorly in that situation?

    As an example of the issues about highlighting isolated situations, let's look at the recent strandings from Cyclone Ului at Airlie Beach, heart of Australia's greatest cruising area.

    By my rough count, 21% of the boats anchored or moored to windward of the rescue base-marina area were multis. That's data from counting moored/anchored boats on Google maps, which may not be representative of the fleet that was in when the storm hit.

    After coming up with that rough count, I then counted the boats pictured stranded or sunk on the SA thread and the linked news report. Eleven monos were pictured on the beach or the seawall or barge ramp, compared to five multis. One mono was in pieces after apparently being crushed by a maxi yacht, but no other mono has severe VISIBLE damage. One cat has a huge hole after hitting the rocks; another cat is pictured with just the vertical bows out of the water. A tri has filled almost to deck level.

    So multis were disproportionately OVER-represented in losses and strandings (perhaps twice as likely to hit the bricks and be lost), according to the (admittedly scanty) evidence.

    Am I saying that multis are more dangerous? NO! NO! NO! I have and will sail multis offshore and greatly respect them.

    The point is that there are major issues in trying to highlight what type went well in a mass stranding. Also, after the Airlie storm where arguably the multis may have come off worse, no one posted anything like "the monohulls faired very well".
     
  14. Paul B

    Paul B Previous Member

    Since statistics don't matter:

    Perhaps it should be noted that NOT ONE of the boats lost at the King's Cup or at Airlie had aft mast rigs, highlighting yet another positive characteristic of that type...
     

  15. downunder
    Joined: May 2009
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    downunder Junior Member

    Poor anchoring gear or improperly set tackle for conditions seems to cause more loss of vessels than any other reason.

    This situation was simply inadequate anchor gear. Adequate gear could have been set up with a dingy and marked by a bouy if not carried on board.

    doesn't matter if mono or multi if inadequate.
     
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