MacGregor 26 not good? Water-ballast in general??

Discussion in 'Motorsailers' started by Tres Cool, Jul 1, 2007.

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  1. mighetto
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    mighetto New Member

    The Tattoo is marketed as a class C Vessel. That means protected bays and lakes and not open ocean. Nothing wrong with that. The M26 boats were always marketed by the manufacture as open ocean vessels.

    I am certain that visualizing a baffled tank system where the water would stay on the high side even without closing the air valve, is possible for you and our readers. I am not going to rip my boat up for pictures. But if you request it, I will sketch out something.

    the badly skippered Mac 26x (drunk) that I think you are referring to was pealing out after a 4th of July fire works display while shooting rockets from the bow hatch. We will never know what happened but the boat did not end upside down. That likely isn't possible owing to the solid flotation configuration. Photos showed the boat on its side and because the 26x will float on its side in calm water without water entering the interior, even with the bow hatch open, I feel safe in assuming that wakes were involved. The subsequent trial cleared the design and put full responsibility on the operator. Nonetheless, I think Roger rolled out the 26m partially owing to the deaths. The 26m has a smaller water ballast tank and 300 pounds of solid ballast. You likely are correct that the 26m and Tattoo must have a full ballast configuration. There are likely "strict operating instructions" for those models.

    But for the 26x, this model was designed to be sailed as a non-ballasted sailboat. That means it was designed to capsize. In fact, dealers held classes on how to right the 26x after a capsize. The second line of the owner,s instruction reads

    Without the water ballast, the boat may not return to an upright position if the boat is tipped more than 50 degrees, and will capsize like most non-ballasted sailboats.

    Given the AC34, it is useful to think of the M26x as a boat with in a boat. The inner boat is catamaran like and is called the water tank. The outer boat is a monohull with a long slot for a forward foil.

    FYI my 26x sports an extra 300 lbs of solid ballast. Any way, what do you think? Were you discussing some other capsize death? As far as I know, in 20 years or so of mac26x operation that July 4th sad event is the only one.
     
  2. Squidly-Diddly
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    Squidly-Diddly Senior Member

    "baffles" are not 'compartments', they are only to slow down flow a bit so you don't have weight slamming around in the tank.

    Motorcycle gas tanks got baffles for that reason (in addition to totally manual 'reserve tank' twin spigot, which IMO is a great idea)


    But I'm not letting go of a "Super Macgregor" with either compartmentalized ballast or bladders in the ballast tanks.
    I think a "1/2 ballasted" Mac would be OK in moderate conditions as it still has 300lbs of centered ballast, and SHOULD (in my non-sailor opinion) sail much better.
     
  3. mighetto
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    mighetto New Member

    There is a super story here that should now be told. The M26x was a direct competitor to a planned TP26. The TP26 was to be the entry point to the Super Series TP52s. The goodness of water ballast was compared to the not good keel foil ballast with vested interests on the not good side pulling out all the stops to disparage MacGregor Yachts using the drunk boater incident as a foil. But it backfired.

    In 2004, an attempt to require a mathematically computed 128 limit of stability in ocean racing designs was orchestrated by those with vested interests in TP52s and TP26s. In a stunning defeat, the Grand Prix (GP) Rule Working Party (RWP) rejected mathematically derived stability requirements.

    The GP RWP did this to support movable ballast designs. Today stability tests for offshore monohulls are performed, not by mathematics, but in test pools where the sailboat must be righted after a capsize simulation. Overnight the TP52s were made obsolete because they adhered to 128 and higher mathematically derived stability ratio. They did this with keel attached weight. Weight that makes them slow when there isn't enough wind to carry them to hull speed.

    We should recognize that if not for the GP RWP (and the extensive study of Macgregor water ballast) we would be living in a very different water world. Likely the AC34 would have been a TP52 affair. I say this because they only run Grand Prix races in the Med with TP52s.
     
  4. rwatson
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    rwatson Senior Member

    Yes it did, check out the towing picture

    http://www.utsandiego.com/news/2011/mar/27/two-dead-boating-accident/


    it was not a 26X or a 26m, but the earlier model involved

    http://www.foxnews.com/us/2011/03/29/boat-grossly-overloaded-charity-sail-killed-father-son/



    yes, the design is sound when operated correctly. Movable ballast is not a viable option on a boat like the macgregor IMHO.


    For a start, the advantage of windward water balance on the centreline, is probably only as great as 100 kilo sailor out on the rails. That is a much easier option.

    next, the optimum sailing angle for speed is only around 6 degrees, so you are better watching your sail positions for better performance than fritzing around with pumping water or whatever
     
  5. mighetto
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    mighetto New Member

    How sad. I was unaware of the tragedy. The capsize risk ratio is important. I think we find that the early 26 in the articles fails the test and that The 26x and 26m clearly pass. But please correct me if you find otherwise. If correct with the math, Water ballast may have nothing to do with the deaths. For review and to possibly get more comments see below.

    The capsize risk ratio was developed after 15 died in the 1979 FastNet. The ratio was designed to penalize boats with a large beam for their high inverted stability and light boats for their response to large waves. Values of 2 and below are ocean passagemakers. Robert Perry, a well known boat designer who favorably reviewed Macgregor's 26 foot sailboats, has adobted some of Roger Macgregor's concepts. When I interviewd Perry he was just finalizing the design of the Flying Tigers. These and the August 2006 splashed Far Harbour 39 are meant to be transported in cargo containers as the Macgregor Yachts are. The FH39 is intended for use by voyaging couples who may wish to protect their investment by economically shipping their vessels rather than make passages that require lots of work or lots of expensive fuel, insurance and repairs. These 39 footers have beams that are one inch larger than the Mac26x and get much of their stability from sharp side chines. They also use aluminum masts, which can be jury rigged if broken - unlike carbon fiber masts - and the masts are deck stepped allowing them to be dropped for weather as well as shipping reasons. Perry classified the 26m as a motor sailer, which I have been uncomfortable with because of fuel capacity and because the 26x and 26m do not have displacement hulls. The boat in the articles is a displacement hull.
     
  6. rwatson
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    rwatson Senior Member

    The early model is definitely more a displacement, sailing design.

    I don't know that the 26X and M are not displacement. I would class them as semi-displacement- as their performance is not as good as a fully planing hull. They have to keep some sailing ability too, after all.
     
  7. mighetto
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    mighetto New Member

    The term semi displacement (in the post carbon era) is called super displacement at least for recent power boats you can see at a boat show. Of course, in enough wind, many displacement sail boats will plane - just before capsizing or breaking up. I think I am correct in saying that the 1988 Macgregor in the San Diego tragedy is a displacement hull form. You need a different hull for true planing. By math, the 26M (reviewed by Perry) has a slightly higher potential for speed under sail when not planing. Her Sail Area to Displacement ratio is 19.067 and the 26X SA/D is 18.677. Most of that potential is owing to sail area, however, and in practice crew competency and sea conditions will determine which vessel performs best. The hull speed for the 26m of 6.437 is not enough of a difference from the 26x ( reviewed exceptionally well by Robby Robinson) at 6.426 for it to be otherwise. Couple that with the finding that the Murrelet (my 26x) sails faster when reefed in many conditions, and one can conclude that both vessels are dissimilar in regards to powering by sail.

    The math shows that both X and M vessels are capable of breaking from displacement speed and reaching a true plane. This is indicated by the displacement/length ratio being under 150. The 26X is significantly better at planing; her D/L is 137.59 vs the 26M’s at 145.61. It probably will take abnormally strong wind (20 knots perhaps) for the M to plane fully ballasted where that potential in the 26X is evident in 12 knot winds, and less depending on the point of sail. I concluded a few years ago that The 26x has a planing Dribbly style hull form. The 26M has more of a traditional rounded River sailboat form. The manufacture's marketing material cover picture for the 26X shows the vessel on plane; no wave form is visible on her length. The 26M, while cooking in good wind, is shown at displacement speeds as indicated by the wave form on her length. She is also being sailed at a noticeable heel, more like a traditional displacement sailboat. These marketing materials show a vast difference between the sailing styles advanced in the two at-first-glance similar power sailers.

    The sailing style of the 26x was intended by the Manufacturer to support speed under sail of 18 MPH. Roger points out that every 100 lbs of extra weight (solid ballast) means 1 mph less speed. Hence, my adding 300 lbs of solid ballast reduced Murrelet's top speed under sail to 15 mph with the factory sails. water ballast becomes very good on down wind points of sail were skilled operators release the water to get rid of weight and plane faster.
     
  8. motorbike
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    motorbike Senior Member

    I really wish I had a 26x, they sound amazing. I was wondering if can they be modified to run subsurface. WIth the addition of extra ballast and a snorkel it could be done and since the water pressure is extremely low, the hatches would not need much work. The sails could be used for silent running as 70% would still be above the water.
     
  9. mighetto
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    mighetto New Member

    Thanks for lightening things up. The chatter about capsize deaths was a bit dreary. Roger filled both the M26x and M26m models up with water so that only the solid flotation supported buoyancy. Then he had several adults loaded into them and pointed out they will not sail well that way. This photo may be what you have in your minds eye

    [​IMG]

    But lets think more about sustainability as it relates to fiberglass and submarines. 750 PBRs were minted directly from Uniflite 31 foot Sports Sedan molds in Bellingham Washington in the 1960s and at least 300 of the Uniflite patrol boats saw duty in Vietnam. The four man PBR crews were trained near Catalina Island in Coronado, south of the MacGregor Yachts factory, as well as in the San Francisco bay where I grew up and their production influenced west coast boat designers and builders such as Roger MacGregor and Robert Perry, if not the designers and builders on the east coast. Perry's Valiant sailboat design was initially produced by Art Nordtvedt, the founder and manager of Uniflite. Water jet propulsion, which is less efficient than traditional propellers became acceptable on the west coast for boat design owing to PBRs. Personal Water Craft share a heritage with the war boats.

    The recent recovery of a half dozen PBR vessels demonstrates that after 40 years the 1/4 inch laminated hulls show no signs of deterioration or warping.

    The major finding regarding M26x cruisers from his book is that dealers told Dr. Cardwell that the M26x has an additional layer of glass fiber throughout the hull than is normal for trailerables. This was done because there was a question about the vibration and pounding the hull would take owing to motoring at wide open throttle with the standard 50 hp engine. It turns out that a thin plastic bottle can work as a submarine:>)
     
  10. Claus Kiep
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    Claus Kiep New Member

    Sailing Power Speedboat

    To have a boat that can speed under power up to 20 - 30 knots and more, and also navigate under sail alone, the catamaran configuration is the most logic ; no ballast needed (!), small and shallow fixed keels suficiente, and lots of space.

    I am working on a 25 ' outboard power cat with the additional capability to navigate under sail alone also.

    Performance optimization is for navigating under power, while under sail speed is not so importante, but the ability to manouver - come about, go to windward.

    I have put a film of a functional RC modell at youtube : SAGAZ 25 Power Sailboat.

    Anyone interested pls mail me under clakiep@terra.com.br , I can send pictures.

    Best regards
    Claus Kiep
    São Paulo/Brazil
     
  11. Claus Kiep
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    Claus Kiep New Member

    Snailboat - great name !

    Motorsailor : seaworthy and fast under power - 30 Knots - and manouverable under sail alone - coming about, going to windward.

    For this task the catamaran configuration is the only logic one : no ballast needed and shallow fixed keels will do.

    I have put a small film in youtube : SAGAZ 25 Power Sailboat

    If You can't find it mail me under clakiep@terra.com.br, I'll send pictures.

    At this size it's no good idea to build it with accomodations, would become
    clumsy, ugly and uncomfortable. But no problem in designing and building same boat in the 35 -40 foot range.
     
  12. gonzo
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    gonzo Senior Member

    The problem of righting a capsized catamaran has not been solved though.
     
  13. Squidly-Diddly
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    Squidly-Diddly Senior Member

    reverse hoist the inflated dingy up(down) the mast, then deploy a sea-anchor and engage a battery powered winch running through a slots on the keels.

    the anchor would be deployed off the beam, and cable would run through(over) both capsized hulls to hopefully give enough shove to get the righting force of the dingy going. once the cat is at 90deg instead of 180, it might flip the rest of the way with the right wave, or use the winch again.

    yeah, its pretty tricky and a few things need to go right, and you'd need to be up for a bit of swimming and not getting snagged swimming around under an overturned sailboat with who knows what lines doing who knows what.

    probably be an After the Storm Has Passed operation.
     
  14. gonzo
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    gonzo Senior Member

    That assumes that the inflatable dinghy is still attached to the boat. Also, that it has attachments strong enough to allow it to be submerged 40-50 feet. Further, there has to be a working halyard and a winch installed under the boat to take it. Lastly, it may be several days before the weather calms; in the lower 40's that could be weeks. Doesn't seem feasible; more like an armchair sailor's fantasy.
     

  15. CT249
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    CT249 Senior Member

    A quick Google shows that the pressure at the top of an inverted 15m mast is about 150 kPa or 300 psi - that's three times the pressure of a normal racing road bike tyre and 50 times the pressure of a cheap inflatable.

    In other words, you're probably going to need some pretty heavy equipment in terms of inflation bags, and somehow rig up some significant air pressure while capsized....assuming the mast is up, of course.
     
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