Ocean Crossing In A Small Boat

Discussion in 'Sailboats' started by venomousbird, Jan 28, 2009.

  1. Chris Ostlind

    Chris Ostlind Previous Member

    Ahh, yes, pull the previous post because it was such a poor example of the English language, spend the time doing an edit that you should have done in the beginning and then reposting the same old blather...


    And some folks on other Fora have referred to you in unflattering tones... now why would they do such a thing? Getting sent to the Sailing Anarchy, You've Been Banned, prison cell for one month... that was just a coincidence?
     
  2. Capn Mud
    Joined: Apr 2008
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    Capn Mud Junior Member

    Guys guys guys............... enough with the bickering which is getting off topic a bit now.

    Any chance of some more responses to the original question?

    I myself was hoping someone might look at my post #37 and respond in some meaningful way.

    Cheers,
    Andrew
     
  3. Tcubed
    Joined: Sep 2008
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    Tcubed Boat Designer

    Capn Mud,

    My honest opinion is that i would not use that boat for ocean crossings.

    Some of the reasons are ;

    Big portholes in hull and huge porthole in cabin. A big wave impact could break one and suddenly make the boat extremely vulnerable.

    Big cockpit. Get a big wave onboard and suddenly the boat is wallowing under an enormous amount of sloshing weight draining away agonizingly slowly so much more vulnerable to the next waves coming up.

    Shrouds set inboard on a bulkhead have never convinced me. The mast is stepped on deck (?) not really a plus either imo. If the roller furler ever jams when a wind is growing , not so pretty either.

    But that is just me and plenty of not so optimal boats have done crossings and lived to tell about it.
     
  4. apex1

    apex1 Guest

    To your last question: naturally you will.. the accommodation is´nt sufficient to house your mistress on such a trip!
    ........... read: comfort is a much underestimated issue on a passage, the lack of it is immediately leading to fatal fatigue!
    To the second: naturally not! What are you doing on such a long trip without your darling?

    To the first: sorry no! As the triple T stated above:

    Big portholes in hull and huge porthole in cabin. A big wave impact could break one and suddenly make the boat extremely vulnerable.
    Big cockpit. Get a big wave onboard and suddenly the boat is wallowing under an enormous amount of sloshing weight draining away agonizingly slowly so much more vulnerable to the next waves coming up.


    Regards
    Richard
     
  5. JotM
    Joined: Jan 2009
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    JotM Junior Member

    "Hull speed"

    I feel sorry about the derailment of the discussion, because I think there is an interesting and possibly very useful discussion (especially for a boat design forum) just underneath the surface here.
    (literally)

    First of all I am wondering how the speed / daily distance was measured by T3 and Whoosh. My guess is by means of a log based on a transducer fitted in or near the keelson. Am I right?

    It just might be so that T3, Whoosh and Chris are all right, as in every one of them.
     
  6. alan white
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    alan white Senior Member

    More amazing things happen when there aren't so many witnesses. That is the nature of reality. Ask any quantum physicist. A Spaniard from the Christopher Colombus voyage took over the helm of Joshua Slocum's Spray when he fell ill, steering a perfect course.
    Nothing is impossible except to exceed the speed of perception.
     
  7. JotM
    Joined: Jan 2009
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    JotM Junior Member

    One can only wittness what one sees

    Am I the only one who figures that the speed at which the water is passing by the hull isn't the same as the speed at which the hull is moving through the water?
    Coming to think of it, I suspect T^3 almost capsized his boat and it didn't even shake him up.

    edit:
    I will work out my thoughts in a new thread I will put in "boat design"'. Off to bed now.
    Before T^3's observation I never realized the danger the combination of the insights of Archimedes with Bernoulli's principle can make us understand.
     
  8. JotM
    Joined: Jan 2009
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    JotM Junior Member

    Where was the measurement taken

    Dear Tcubed and Whoosh,

    I still do care about your answer. How and where did you measure your speed / daily distance? (A log? In that case, where was the transducer placed?)

    Regards,

    Jaap
     
  9. Tcubed
    Joined: Sep 2008
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    Tcubed Boat Designer

    Well had i known the show that would ensue after posting best days runs i would have omitted that detail. My intent was only to illustrate an example of a suitable small ocean crossing boat. But now it's there, so let me expound some.

    Local flow velocity is indeed different to far field velocity. That is how foils work and indeed the whole study of fluid dynamics. The boat's velocity is always defined as far field. Therefore hull mounted paddle type logs will always measure faster than far field velocity and should be calibrated for the particular hull and log position on said hull. As for logs that trail on a string they're much more bother than they're worth.

    I bought the boat and it had a skin mounted paddlewheel type log, depth sounding bump and a host of other through hulls every single [1] one of which i removed. I also stripped the underwater hull of all paint and rebuilt with many layers of primer and paint and a lot of sanding in between, so the bottom was about as good as it could get.

    My measurements were purely from position , therefore over ground. Like i said before there is according to the charts between 0.5 and 1.0 SW current in that area. It can't have been more because the sea state would have been less. Anyone familiar with sailing in areas with current knows how powerful the effect of current is on sea state. In fact some of the most terrifying seas i've seen have been current against wind. The wind was 35 to 40 NE , my course roughly SW. The sky was mostly fair, the seas as expected for that wind. There is always a bit of water shear (wind dragging surface layers of water along) though, which is additional to current . I had no way of measuring that so one must use one's best deductions, as i've just stated above.

    I did get pooped a couple times[2] during that stretch and i slept fitfully constantly nervous about broaching, but never did the boat waver more than 15 deg off course. That to me is what is remarkable about this , not the speed itself. In fact i am from the school that says that without control, theoretical speed remains just that, theoretical. In the whole crossing i only steered an hour at the beginning and an hour at the end. I'm waaay past the point where i think steering is fun. I used two different sheet to tiller methods depending on wind angle, which worked very well. Kind of a pain to set up for every sail change but very simple, cheap (required material; couple blocks, some line and some good bungee cords) and extremely effective.

    [1] actually i did leave one through the transom just below the deck , for the bilge pump.

    [2] the boat used to have an open cockpit which i solidly decked over, thus making the stern flush decked and creating a comfortable and ample sleeping area aft (who on earth wants to sleep in crews' quarters in the bow?, give me captains quarters aft any day, thank you!) which would not have been possible with the engine in the way also.
     
  10. wavepropulsion
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    wavepropulsion Pirate Member

  11. diwebb
    Joined: Jun 2008
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    diwebb Senior Member

    Hi Tcubed,
    as discussed in my previous submission, I believe that you are sincere and honest in your statements and that your detractors underestimate some of the factors which you have declared in your posts. The effect of the south westerly current and the surface current created by the sustained powerful winds could have affected your over the ground speed by as much as three knots. This would bring the actual through the water daily runs well within the theoretical hull speed of the boat. I have experienced this effect on a number of occasions and posted short and daily runs that without these factors would appear to be impossible on a thereoretical designed speed basis. It seems that your detractors have never experienced the conditions that created your run, so are speaking from a theoretical basis not from a real world knowledge of the subject. However it still must have been one hell of a ride!!

    All the best,
    David
     
  12. diwebb
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    diwebb Senior Member

    Hi, back to the original subject of this discussion. T cubed's assertion the an Itchen Ferry style of boat makes a suitable small offshore cruisng boat is one that I agree with wholeheartedly. The Pardeys Serrafinne and Talesin designed by Lyle Hess are both based on this style of hull and have performed very well in their total of three circumnavigations. The Bristol Channel Cutters also designed by Lyle Hess are very good cruising boats and many of them have cruised extensively. The Bruce Bingham designed Flica, built by Pacific Seacraft is a bit small in my opinion but many have completed creditable long cruises, they are again similar in many respects to the Itchen Ferry. So if looking for a small cruising boat one of the Itchen Ferry type would be my recommendation as well.
    Another type that has also cruised extensively is the Dory yacht as designed by Jay Benford, his designs start at about 26 feet and go up to 37 feet long and many of them have made creditable and safe cruises.
    David
     
  13. science abuse
    Joined: Nov 2009
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    science abuse Junior Member

    Having a bit in common with the origional poster (That being little experience with aspirations of great journeys), I think the nature of the suggestions are somewhat missing the point:
    This gent just wants to do it, not do it fast. It seems like he's only got two basic requirements:
    -Big enough to live in.
    -Wont break/sink when it gets knocked down.

    With secondary requirements being "keeps my stuff dry", and "easy to single hand".

    He doesn't need an Open 30 when a Suhaili will get him there. He could probably make it in a Lightning, if there were room for the massive balls required to cross an ocean in one. :)
     
  14. Harold B
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    Harold B Junior Member

    After over 21 years commercial fishing on large and small boats I have some points to make. The first consideration is safty, the second is adversity. What will the boat do to make me miserable, I am not joking some boats will beat you to death on any voyage longer than a week. You definatly (times two) want a sea kindly boat that means a long water line and wieght. I have been on smaller fiberglass fishing boats that were light wieght that had a quick motion, the owners added three tons of lead outboard in the bilges to slow down the quick rolling motion and make the boat more sea kindly and usable without beating the crew to death. A lot of smaller vessels are completly able (technacally) to cross oceans but the crew will suffer greatly in these little ocean going torture chambers. Captian Joshua Slocum wrote a book about circumnavagating the world single handed and his boat the Spray was a good choice by an experienced mariner. The only change I would make to his vessel is to go to a schooner rig to have more easily handled small sails than a few large sails and to make self sailing a reality not just a wish because after more than an hour, the helm becomes a cruel tyrant. Read Joshua Slocum's book, adventure should be more than a exercise in discomfort.
     

  15. science abuse
    Joined: Nov 2009
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    science abuse Junior Member

    That is one of the most quotable posts I've seen on this forum. Thanks for the insight, Harold.
     
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