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

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

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  1. Claus Kiep
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    Claus Kiep New Member

    1990 I finished a 44' catamaran - wood, system WEST, deep V parabolic hull shape, a modified version of a Eberhard Fischer design. I corresponded with Derek Kelsall who offered a righting system, which consisted of several water ballast tanks, pums, valves and hoses, to get the bows of a inverted floating catamaran under water righting it by a pitching movement backwards. Not only that the system was quite clumsy and complex - I realised that for me to trust it, I would have to capsize my boat intentionally in order to make sure it works ! Is anyone prepared to do this to his boat ?
     
  2. rwatson
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    rwatson Senior Member

    "Len Surtees had designed Outward Leg to be extremely light, fast and seaworthy and in a first--to be self-rightable. Outward Leg was launched upside down and left like that for one week before being self-righted, stocked with provisions and sailed off around the world by Tristan. At the time the boat was hailed as the first re-rightable trimaran in the world. "

    http://www.thebeachcats.com/OnTheWire/wwwcatsail/archives/v3-i3/feature2.htm
     
  3. Claus Kiep
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    Claus Kiep New Member

    Motorsailor

    Surely You can't build a boat that is perfect for power and sail at the same time. Besides the need to compromisse, You need to put emphasis on one capability and have the other performing 'also'. Thats the idea behind my Project SAGAZ 25 Power Sailboat wich can be seen at Youtube.
     
  4. Squidly-Diddly
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    Squidly-Diddly Senior Member

    Yeah, plus when that hi-pressure air comes up it expands and would pop just about anything, even with a big relief valve, since the more it expands the faster it wants to rise.

    Maybe deploy a seaanchor/raft off the beam and run lines from top of mast (pre-rigged) and over(under) the hulls.

    Mostly I've got faith in a powerful, sealed battery/winch unit which could pull hard and fast enough to get things going before the seaanchor line is used up.

    Also include a way to deliberately flood either hull (pull a cork in the keel to let air escape) to help the hull that is getting submerged during the flip do so.


    Since its nice to have an easily dis-mountable/dropable mast, have a mast that can be lowered(raised) when the cat in turtled, then attach floation and raise(lower) mast to flip the boat.

    Maybe think of flipping bow/stern vs sides, just because it might use the asymmetric to advantage, even though beam is narrower.


    OR...how about ROCKETS! Seems rockets can be engineered pretty well to sit all nice and sealed up until a one-time use. Like Ejection Seat rockets, or RATO(rocket assisted take off). If that stuff has been around for 1/2 century then there should be a way to do it for a commercial ap at a reasonable price. .https://www.youtube.com/watch?v=5gXfK4ypirI

    Maybe something derived from those Russian rocket powered torpedoes.
     
  5. schakel
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    schakel environmental project Msc

    Macgregor 26.jpg
    Sometimes, to my shame, I am member of Sailing Anarchy and the MacGregor 26 was long time the most bespoken boat because it was ugly.
    Sorry, I can't do anything about that.

    The "new ugly" is white pearl. I think as a cocktail platform she is at least note worthy, but I am waiting to see her sail. I expect less performance then Malthese Falcon but.. This one has more tonnage. What do you think?
    white pearl.jpg
    But very beautifull is this one:
    foggy-notion1.jpg
     
  6. CT249
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    CT249 Senior Member

    Interesting. Tristan Jones claimed to have invented the system AFTER Outward Leg was launched. But then again, Tristan Jones was an inveterate liar who really cannot be trusted.
     
  7. rwatson
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    rwatson Senior Member

    Huh ? Len Surtees INVENTED it, Tristan sailed it. They showed the launching on a documentary about Len Surtees a few weeks ago.
    http://www.surteesmultihulls.com/about.html

    "I successfully launched my trimaran Osprey upside down and by my self, re righted her by rotating end over end, not side ways because the flow of water and air is better controlled this way, the innovative smart keel also played a big part in this. Osprey in 1980 became the first ocean trimaran to achieve this feat."
     
    Last edited: Dec 14, 2015
  8. CT249
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    CT249 Senior Member

    As I said, Tristan Jones was an inveterate liar. He made up most of his own "life story" and most of the stories he sold. As a kid I loved reading his stuff until he let the cat out of the bag when he claimed that he was at the sinking of the Scharnhorst while aboard the destroyer HMS Chieftain. No such destroyer existed so not only was he a liar, he was a sloppy liar.

    Jones claims that many people ripped him off but given that he appeared to be completely untrustworthy I'd bet he was the person doing the off-ripping (to coin a phrase) which is something other people confirm. That's why I thought it was "interesting" that he claims to have invented the "cool tubes" system. Apologies if I did not express it clearly.

    FWIW I'm still quite dubious about the chances of any crew actually getting around to using any offshore multihull recover system in real life.
     
  9. rwatson
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    rwatson Senior Member

    You mean this one attached. "The Incredible voyage"

    The HMS Chieftain certainly DID exist.
    https://en.wikipedia.org/wiki/HMS_Chieftain_(R36)

    "HMS Chieftain was a C-class destroyer of the Royal Navy that was in service from March 1946, and which was scrapped in 1961."

    PS "The Battle of the North Cape was a Second World War naval battle which occurred on 26 December 1943" thats a long time before the Chieftain was put into service,


    To be fair, he doesn't say the Chieftain sank the Scharnhorst , he just states he was on the Chieftain at the time the Scharnhorst was sunk, and he certainly was in the Navy.


    PS - extra info - found a more definite claim about the Chieftain and the Scharnhorst , but not any extra validation yet

    https://books.google.com.au/books?i...DoAQhMMAk#v=onepage&q="hms chieftain"&f=false


    If you lookup his Wiki P page, it says that there was a lot of invention in his books, which I guess is about right for authors, but certainly, his claim to being on the Chieftain could be totally factual.
    No it couldnt - WW2 finished in 1945, Chieftain went into service in 1946.

    Ah well - its official, its all fiction :rolleyes:
     

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    Last edited: Dec 14, 2015
  10. CT249
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    CT249 Senior Member

    No such destroyer existed at the time Jones claimed it did. Apart from a couple of the Cas, none of the C sub-classes served in WW2. None of the Cas were launched at the time of the Battle of North Cape. The earlier C-Class of the 1930s had been sold to Canada years before.

    There are plenty of books that describe the Battle of North Cape. No destroyer that was remotely like "HMS Chieftain" was there. Chieftain could perhaps have been a pseudonym for a Tribal class destroyer, but none were there.

    The story you linked to was the one I recall, but the addendum in italics was not in the Oz Seacraft version. The version in the link contains even more lies. The cruiser Cumberland was not there as he claims, although that's an understandable mistake since she served in the area and her sister Norfolk took part in the action. The Sheffield was there but he ignores the Belfast. Not one of the destroyers he lists was there, nor where any bombers present on that stormy night.

    The odd thing is why he didn't bother to cover his tracks by just pretending to have been aboard one of the S class, M class or other destroyers there. He could even have pretended to have been on HMS Belfast and gone on board her to get some background.

    Jones made up an enormous amount of his stuff. He was not Welsh, he did not serve with Tansy Lee (if I have the name right) on a barge, nor in WW2.

    The book on Jones that explores this is Wayward Sailor - not his Saga of a Wayward Sailor, but a well researched work that blows most of his claims apart.
     
  11. sharpii2
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    sharpii2 Senior Member

    Actually, the water pressure, or I should say water over pressure, at that depth is only about 23 PSI, no where near 300.

    Donald Crowhurst was one of the first to mount an air bag at the top of his tri.
    It was supposed to be triggered by a central switching system, which, due to the rush to get to sea (in time for the "Golden Globe" race), was never hooked up.
     
  12. sharpii2
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    sharpii2 Senior Member

    The water pressure, or I should say water over-pressure, at 15 meters is only about 23 PSI, nowhere near 300.

    I believe Donald Crowhurst was one of the first to use an air bag at the top of the mast of his tri. It was supposed to be connected to an electronic switching station, which he called "the computer", but never was, due to the rush to get his boat to sea (for the "Golden Globe" race).

    If used in large waves, it is concievible that the system might work. The mast would have to be pointed to windward, when it came up. The height of the wave crest and the force of the wind might do the rest in tipping the boat past its "stable 2" point of no return. All this assumes, of course, that the rig and airbag stay intact. Pretty much the same assumption made with a canting keel boat. If the keel canting mechanizm fails on the wrong side, once the boat is inverted, it may never come back up.
     
  13. CT249
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    CT249 Senior Member

    I did some more checking and the available information seems to vary hugely, which is odd. I really should have listened in my science classes instead of doodling boat designs.

    One salvage-bag manufacturing company, which would probably be pretty reliable says you get 29.4 "ambient pressure" at 33' and 44.1 at 66', which I assume is PSI since their other units are imperial. Either way, it looks as if my source was wrong; sorry.

    We still seem to be dealing with significant pressures and forces. And the salvage bag has to be inflated without getting punctured and without anyone getting hurt; there's a pic of a very large air bag going 150' in the air after coming loose. As the mast came up the leverage would increase, which may mean that the re-righting will end up being very fast - what do the crew do during the 90 degree rotation? And of course, what happens when the boat is at 90 degrees? Yes, you can flood a tri hull and then pump it out but that doesn't seem to add much leverage until the boat is already coming upright. Finally, it all depends on the mast staying up, of course.

    It still sounds like an enormously complicated operation with enormous potential to go wrong.
     
  14. sharpii2
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    sharpii2 Senior Member

    I do agree that a lot could go wrong, but I don't agree that it's that complicated of a process. Hell, you could have a bicycle pump on the other end of the hose. But really any high pressure gas tank will do.

    IIRC, Crowhurst's system was supposed to trigger once the boat tipped beyond a certain point, so really it acted more like a car airbag than a salvage airbag.

    If you look at some pictures of some multies taken during the '60's you will see some had permenant masthead floats. These were intended to keep the boat from turtling.

    Unfortunately, even if the float/airbag works as planned, the boat will still be still capsized well past the point of no return. And this capsize will be down wind.

    Only if the rig stays intact long enough for the boat to turn around, so the mast points upwind, will there be hope of the wind an wave combination to tip it again, this time past the stable 2 point of no return.

    Earlier large multis had masthead rigs which had to be incredibly strong, as they were stiff and the hull form offered little resiliency to make up for that, were plenty strong enough. Later fractional rigs (whose resilency helped a great deal on reducing ultimate rigging loads) probably weren't.

    I don't recall ever hearing of such a system facilitating a self-rescue, and I used to read a lot of multi literature.

    On a ballasted mono, with a reasonable range of stability, like say 110 degrees, such a system would be more promising.

    If you look at some old pdracer pictures you will see some of them had a Clorax(r) bottle lashed to the mashead.

    Rules one, two, and three about large multi capsize are simply "Don't".
     

  15. CT249
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    CT249 Senior Member

    It's perhaps not that complicated when sitting at a keyboard. Do get it right when possibly verging on hypothermia and wet, with the boat rolling around and possibly the huge force of waves sweeping stuff around through the boat may be a lot more complicated. Things like working out where the crew will be when the boat starts to recover - where can they find somewhere where nothing will fall on them, and where they will not fall? Are those places away from the mast heel, which could misbehave? Will the inflating bag get tangled in the spinnaker that could be washing around the masthead? What about the anchor and rode that could have fallen out from the anchor well? Can you read the controls on the air tank properly, upside down by torchlight? What's going to happen if the sails are still sheeted on as the boat starts to re-right? The forces involved there would be interesting, I'd have thought.

    Yep, I know about the masthead floats on some Comanches or something like that, and others. I'm not sure if they ever worked.
     
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