Raised Helm Deck for Inlet Surf Running Idea

Discussion in 'Boat Design' started by DouglasEagleson, Mar 9, 2016.

  1. PAR
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    PAR Yacht Designer/Builder

    Yeah, that's what I gathered from this OP as well and nothing but some real sea time will help and maybe as we've pointed out, some aquance with a book or two.
     
  2. pogo
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    pogo ingenious dilletante



    Wow !!!!!!

    pogo
     
  3. PAR
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    PAR Yacht Designer/Builder

    Downbursts happen (microbursts, whatever) and they weren't as well understood then, but force 5 winds don't generally experience hurricane force downbursts.

    You seem to remember things different than the folks that were there. Over 300 yachts started, 5 actually sank, 100 got knocked down with 75% of these turtling and yes, a devastating 15 dead competitors and maybe as many as 6 non-competitors. The after reports showed clearly unsuitable designs in the mix, ill conceived heavy air tactics and an unfortunate set of circumstances for some. I called my buddy and he reports that they recorded 975 hPa at the height of the worst of it and force 10, maybe borderline 11 for a short period. These aren't condisions most sailors have ever seen. No one in these condisions, in any era typical racing yacht, can expect to come through without damage and all will be praying for some luck.

    As to the "exact weather" well, you've not been paying attention, as mother nature is a finicky witch, though now we do have much better prediction capabilities and better yachts too. As to the "pattern" that rolled over south Island that day, we know pretty much exactly what happened, which is the usual benefit of hindsight.

    Lastly, there's no such thing as a force 5 storm. You might be puttering along in 19 knot winds, maybe thinking about a reef when the lovely force 5 gets pushed out by and gale, but this isn't a force 5 storm, it's a gale and you'd have seen it coming if you'd been paying attention, as my friend reminded me. They noted the pressure continuing to drop and winds continuing to build, so acted accordingly and where one of the 2/3's of the fleet that didn't get knocked down. They were one of the 1/4 of the fleet to finish, but they took some damage, though modest. Much of the larger boat portion of this fleet, managed to stay ahead of the worst of it, but 975 hPa is hurricane level low and 30' to 40' yachts, aren't the best thing to challange force 10 and building wind strengths.
     
  4. messabout
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    messabout Senior Member

    I have been sailing and power boating for more than 60 years. So far I have never seen a storm so sudden that I did not notice the approaching warning in the sky. I don't even call myself a great seaman, but I do pay attention to what is approaching or ever possibly approaching, even on a beautiful sailing day.

    You may be interested in the book by a British meteorologist and avid sailor named Alan Watts. The title of the book is : Wind and Sailing Boats. Microbursts and all that sort of thing are nicely covered in that book. The late Stewart Walker was also a brilliant weather analyst and sailor. His books are also most informative. I mention books as a follow up to Pars' suggestion.

    No offense here. We are all in this together and we care very much for the survival of our peers.
     
  5. PAR
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    PAR Yacht Designer/Builder

    I too have never been surprised and placed in survival condisions, I didn't know where come for so time previous. I have a had a summer squall roll over me and go from a fresh breeze to a half a gale and a few full gales. This can happen inside a half hour. It's not uncommon here in the summer, but you look up and say crap, we're going to get hammered and start doging stuff down.
     
  6. DouglasEagleson
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    DouglasEagleson Junior Member

    I can obviously not be considered.

    But the issue is the weather that causes the deadly events. Here is the questiob;

    WHAT caused 3 kilometer diameter tornados versus the classical spout.

    If the Fastnet race was over hurricane speed, cause is the issue.

    I have no proof but I suspect the 3 kilometer diameter tornados exist when sailing. And I suspect that the "Perfect Storm" system had one such tornado at the center.

    Convention theory has what rules? So my rule making is to be prepared for survivorship through said tornados.

    Said events are worse than hurricanes.
     
  7. DouglasEagleson
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    DouglasEagleson Junior Member

    spout Issuess

    The lost bridge event appears to be a vacuum pressure event. The bridge was airtight almost. So when a spout sat on the window the vacuum broke the window and an airliner like decompression ejected the crew out the window.

    The window was undersigned or equilibria vents did not exist to cause a calm vacuum in the bridge. It is how people survive in their house cellars. The funnel spout winds are just horizontal with a small upward vector. So the wood cellar roof typically survives intact. The occupants experience a vacuum loss of breath for just a moment.

    A good hatchway withstands the horizontal spout winds. But airtight cabins are not anything but opposite of the need to allow vacuum into the cabin controlled. A good idea is to make a mylar blowout flanges on the hatches.

    The meaning is to design to full vacuum containment or have vents.

    Spouts are easy to design for. The large tornados have such a powerful wave action that the crew to wall impacts will kill. I believe.

    The largest reliable wave height in general I have heard of was a 100 footer. SO plan on falling off one. So ultimate survivalhood requires some kind of elastic strapping in the cabins.

    Submarine style design might help?
     
  8. DouglasEagleson
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    DouglasEagleson Junior Member

    Back on topic

    The helmsman station over the dinghy davits can be done without actual dinghy use. The mounting design is a strength issue. A torsional force would exist if the boat was knocked down fully. The station walls would hit the water.

    A breakaway design is not allowed so a type of mounting frame is required. The load would have to be distributed to the deck or the hull or both. And putting in station walls that flap open when a wave hits the sides. Two way flapping walls with bungee cord to hold closed position. This way it could be used for foul weather and not just inlet surf.

    With no wall effect, the torsional mount design is easy.
     
  9. gonzo
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    gonzo Senior Member

    There are no tornadoes at sea, only in your imaginary world. Waterspouts have little energy and don't cause any real damage. You should spend some time at sea and stop smoking whatever it is you do. That will give you an idea of what happens in real conditions,.
     
  10. tom28571
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    tom28571 Senior Member

    "What we have here, is a failure to communicate"

    Strother Martin, Cool Hand Luke
     
  11. PAR
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    PAR Yacht Designer/Builder

    I'd add a lack of understanding as well.
     
  12. gonzo
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    gonzo Senior Member

    I think that the "Two way flapping walls with bungee cord to hold closed position" will go into the anals of this website. That one in hard to beat ;)
     
  13. CT249
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    CT249 Senior Member

    It wasn't a Force 5 in the 1979 Fastnet - as others have said, that's a nice sailing breeze. Even a lightweight 28'er like mine is still under full sail in F5.

    Low Y was up to Force 11 in strength when it hit the Fastnet fleet, which means the wind pressure was NINE TIMES greater than F5. There was NOT "heavy fin keel damage to all survivor craft". There were 303 entries and less than 2% suffered hull damage. Not a single one of the boats reported anyone "blown away" as you claim and if you had any significant experience you would recognise that such claims are just silly.

    All this in on the internet. If you want people to take you seriously why not do some research?

    It seems exceptionally arrogant of you to claim that you want "use the brain" to make running bars easier - it implies that you think you are the first person to do so. Maybe you should respect other people and their experiences a bit more.


    EDIT - I didn't notice PAR had already pointed out how wrong your Fastnet claims were.
     
  14. CT249
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    CT249 Senior Member

    Maybe they weren't in the fairly localised area of really bad weather? I know guys who went through the storm well enough to win the Admiral's Cup (which was then effectively the world ocean racing title, and in which it was the last race) and they feel it was a fairly hard blow. Boats like Impetuous and Police Car (3rd and 5th overall, I think) were down to storm trysails if I recall their lectures here in Sydney after the race.

    One of the most common comments from the Aussie crews was that the problems may have been linked to the lack of storm trysails under UK rules, When the winning team in the race says that you needed a storm trysail (and only a storm trysail) then it must have been stronger than a double reefed breeze.

    What "daysailing" boats were involved? Perhaps Gunslinger (Hustler 32) and even Grimalkin (Nich 30) could be described as such, but they were designed for Cat 2. Most of the dead were from boats like the Ohlson 35 Flashlight and the Carter 33 Ariadne, which were conventional masthead rigged medium displacement offshore racers of the typical '70s style - in fact Flashlight (which lost two crew) was more of a cruiser.

    We don't really know if the problem was boat design, as there were almost no conventional full-keel or cruiser types in the race. Had there been they could have done badly, as they have in Hobarts. Flashlight was one of the closest to a classic modern cruiser, and she lost two crew. Trophy wasn't a real IOR boat and she lost about four.
     

  15. PAR
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    This is the same guy that has a come to the conclusion that "plywood boats need to have no keel seam" and has come up with a seemingly wonderful moisture trap, to retro fit plywood boats with (< http://douglaseagleson.blogspot.com/ >)

    It would seem a similar lack of engineering understanding as well. On a lighter note, he is offering some jet printer versions of his "Dark Abstract Surrealism" artwork, which might explain a bit.

    [​IMG]

    I think this one titled Tiger is my favorite, though there's plenty of others to satisfy the darkest amongst us.
     
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